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17 pages, 2938 KiB

Open AccessArticle

Propensity of Predator Mimicry in Steller’s Jays

by Trinity C. Harvey, Pia O. Gabriel and Jeffrey M. Black

Birds 2024, 5(1), 173-189; https://doi.org/10.3390/birds5010012 - 9 Mar 2024

Viewed by 1490

Abstract

Avian vocal mimicry has been described in a variety of contexts, suggesting its function is multifaceted within and across species; however, basic empirical data describing mimetic signal prevalence and context are lacking for numerous species. We examined the occurrence and context of mimicked [...] Read more.

Avian vocal mimicry has been described in a variety of contexts, suggesting its function is multifaceted within and across species; however, basic empirical data describing mimetic signal prevalence and context are lacking for numerous species. We examined the occurrence and context of mimicked Red-shouldered Hawk (Buteo lineatus) calls over a 12-month period in a population of 49 individually color-marked Steller’s Jays (Cyanocitta stelleri). We documented mimicry of Red-shouldered Hawk calls in 14 of 49 (28.6%) jays during this 12-month period. We also reviewed the occurrence of the behavior in historic observation data. Hawk mimicry occurred more often during the early breeding season when jays were within home territories, their mates were present, and aggression was absent. Younger, larger, and bolder jays were most likely to perform imitations. These results suggest jays individually vary in mimetic propensity, and individuals’ proclivity for mimicry may be influenced by social and ecological contexts, physical characteristics, and personality traits. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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18 pages, 3587 KiB

Open AccessArticle

Identification of Novel Can Manipulation Behaviour in the Common Raven (Corvus corax)

by Rebecca Dickinson and Loni Loftus

Birds 2024, 5(1), 155-172; https://doi.org/10.3390/birds5010011 - 8 Mar 2024

Viewed by 2120

Abstract

This study examines the common raven (Corvus corax) population on Lanzarote, Spain, at a previously unstudied site. The study aimed to compare the use of camera trap technology and human observation in capturing a wide repertoire of raven behaviour and pay [...] Read more.

This study examines the common raven (Corvus corax) population on Lanzarote, Spain, at a previously unstudied site. The study aimed to compare the use of camera trap technology and human observation in capturing a wide repertoire of raven behaviour and pay close attention to the perforation of aluminium cans, a behaviour that has not been described in the scientific literature previously but has been reported anecdotally through human observation. Five cameras were sited over a period of 6 months, with three aluminium cans placed at each location. One of the three cans was baited with meat and eggs, mimicking wild feeding substrate. Human observations took place over the same period of time in the same locations. Raven sightings were highly correlated in human-inhabited areas as well as agricultural areas, seemingly linked to food acquisition. Camera trap technology identified a greater number of can-orientated behaviours (interaction, manipulation, peeking inside, and pecking) compared to the human observation method. Conversely, human observation yielded a greater number of non-can-orientated behaviours (analysed as a group) when compared to that of camera trap observation. Overall, there was a significantly greater number of ravens observed via human observation when compared to that of camera trap observation. Initial evidence suggests that ravens only perforate cans they deem salient in terms of food acquisition, with beer cans being the most common focus of the behaviours observed, possibly linked to olfactory stimuli, the movement of the can or learned behaviour relating to reward acquisition. This study presents new data regarding object interaction in ravens, adding to the current body of knowledge. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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10 pages, 721 KiB

Open AccessArticle

Zebra Finch Females Avoided the Scent of Males with Greater Body Condition

by Luisa Amo and Isabel López-Rull

Birds 2024, 5(1), 127-136; https://doi.org/10.3390/birds5010009 - 6 Feb 2024

Viewed by 1629

Abstract

The role of chemical communication in the social relationships of birds is receiving growing attention, but our knowledge is still scarce compared to that of other taxa. Previous evidence suggests that chemical cues emitted by birds may carry information about their characteristics, which [...] Read more.

The role of chemical communication in the social relationships of birds is receiving growing attention, but our knowledge is still scarce compared to that of other taxa. Previous evidence suggests that chemical cues emitted by birds may carry information about their characteristics, which may be useful in the context of sexual selection. However, experimental studies are needed to investigate the role of bird chemical cues in signalling the quality of potential partners. We performed an experimental study aimed at disentangling whether the female Zebra Finches (Taeniopygia guttata), use chemical cues to assess the body condition of potential partners. We offered focal females (N = 28) the scent of two males differing in body condition (body mass/tarsus length ratio) (N = 28 scent donor males). Our results showed that females can assess the body condition of potential partners using olfaction. However, contrary to what should be expected in a mate choice context, females avoided the scent of males with greater body condition. Our results, therefore, suggest that, despite performing the study during the breeding period, social interactions may be mediating the avoidance of the scent of the male in better condition in this gregarious species, probably to avoid a conspecific competitor with better body condition. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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23 pages, 5821 KiB

Open AccessArticle

Nestling Diet of Two Sympatric Insectivorous Passerines in Different Habitats—A Metabarcoding Study

by Daniel Höhn, Juan F. Masello, Marc N. Kümmel, Sven Griep, Alexander Goesmann and Petra Quillfeldt

Birds 2024, 5(1), 67-89; https://doi.org/10.3390/birds5010005 - 23 Jan 2024

Cited by 2 | Viewed by 2104

Abstract

Increasing landscape transformations and urbanisation affect insectivorous bird populations in various ways such as food availability, breeding phenology, or reproductive success. Especially during the breeding season, many passerine birds rely on the availability of caterpillars as the main prey for their nestlings. Previous [...] Read more.

Increasing landscape transformations and urbanisation affect insectivorous bird populations in various ways such as food availability, breeding phenology, or reproductive success. Especially during the breeding season, many passerine birds rely on the availability of caterpillars as the main prey for their nestlings. Previous studies suggested that similar diet preferences of sympatric species may result in interspecific competition, as demonstrated for Blue and Great Tits in forest habitats. However, nestling diet and prey preferences in other habitats are not fully understood. Prey availability, especially caterpillars, is lower in cities than in forests, thus influencing prey choice and interspecific competition. Here we used faecal DNA metabarcoding to investigate if nestling diet composition of the two sympatric species Blue Cyanistes caeruleus and Great Tits Parus major varied among species and different habitats (forest, traditional orchards, and urban parks). Furthermore, we examined food availability by DNA barcoding of the arboreal arthropod communities among habitats and compared them to the nestling diet to infer parental prey selectivity. The study was carried out in central Germany from 2018 to 2019. Blue and Great Tits showed a diverse diet which was dominated by Lepidoptera in all habitats. Lepidopteran diet components were most similar between forest and orchard sites, as were the components with other arthropods between orchard and urban sites. Both tit species showed selectivity for the lepidopteran families Geometridae and Tortricidae in all habitats, and for Noctuidae (Lepidoptera), Tenthredinidae and Braconidae (Hymenoptera) in forest and orchard sites. As the tits showed preferences for mainly families of Lepidoptera, and Hymenoptera, our approach provides a baseline to support monitoring of these groups. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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8 pages, 249 KiB

Open AccessCommunication

Sex and Age Bias in Australian Magpies Struck by Aircraft

by William K. Steele and Michael A. Weston

Birds 2023, 4(4), 295-302; https://doi.org/10.3390/birds4040025 - 27 Oct 2023

Cited by 2 | Viewed by 1540

Abstract

Wildlife–aircraft collisions represent a safety and financial challenge, necessitating site-specific hazard assessments, which are generally based on species’ attributes and collision frequencies. However, for many bird species, collision probability and risk may not be distributed equally among individuals, with sex and age differences [...] Read more.

Wildlife–aircraft collisions represent a safety and financial challenge, necessitating site-specific hazard assessments, which are generally based on species’ attributes and collision frequencies. However, for many bird species, collision probability and risk may not be distributed equally among individuals, with sex and age differences possible but rarely examined. We examine Australian Magpies, a resident, grassland species of bird in southeastern Australia frequently involved in collisions with aircraft at airports, and which can be sexed (adults) and aged. We compared collision rates recorded at Melbourne Airport, Victoria, Australia, with airside counts of magpies, recording, when observable, the sex and age of the birds. Adult females and males were similarly abundant at the airport (46.6% female), but females were struck relatively more frequently than males (78.1% female). Juvenile (first-year) magpies were struck more frequently than expected based on their representation in bird counts. We show an example of where some demographic groups within species represent higher hazard potential to aircraft than others, and management which manipulates demography of magpies at and near the airport (such as discouraging local breeding and targeted harassment/dispersal) may be fruitful. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

11 pages, 2047 KiB

Open AccessArticle

Life History and Sociality Predict Variation in Eye Size across Birds

by Guy Beauchamp

Birds 2023, 4(3), 284-294; https://doi.org/10.3390/birds4030024 - 23 Aug 2023

Cited by 3 | Viewed by 1962

Abstract

Over evolutionary times, the eye has acquired several adaptations to improve feeding efficiency and reduce predation pressure. Eye size, in particular, represents a target for selection, as it affects light capture and image resolution. Previous research on variation in eye size across species [...] Read more.

Over evolutionary times, the eye has acquired several adaptations to improve feeding efficiency and reduce predation pressure. Eye size, in particular, represents a target for selection, as it affects light capture and image resolution. Previous research on variation in eye size across species has focused on ecological factors related to light availability and foraging needs. Larger eyes are also thought to allow species to detect distant predators more easily, but this conjecture has not been examined across species. I predicted that risk-averse species or those exposed to high predation risk benefit from relatively larger eyes to enhance predator detection. To test the prediction, I performed a comparative analysis involving 660 species of birds while controlling for phylogeny, body size and other known ecological correlates of eye size. The results show that species at the slow end of the life history continuum, which emphasize survival over reproduction and are expected to be risk-averse, have evolved relatively larger eyes. In addition, solitary species, which cannot rely on others in their groups to decrease predation risk, are also characterized by relatively larger eyes. The results indicate that predation risk, through its association with life history and sociality, is an important ecological factor in the evolution of eye size across species. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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9 pages, 1242 KiB

Open AccessCommunication

Highly Conserved Microchromosomal Organization in Passeriformes Birds Revealed via BAC-FISH Analysis

by Marcelo Santos de Souza, Suziane Alves Barcellos, Victoria Tura, Vera Lúcia Bobrowski, Analía Del Valle Garnero, Ricardo José Gunski, Darren K. Griffin and Rafael Kretschmer

Birds 2023, 4(2), 236-244; https://doi.org/10.3390/birds4020020 - 16 Jun 2023

Cited by 2 | Viewed by 1754

Abstract

Passeriformes birds are widely recognized for their remarkable diversity, with over 5700 species described so far. Like most bird species, they possess a karyotype characteristic of modern birds, which includes a bimodal karyotype consisting of a few pairs of macrochromosomes and many pairs [...] Read more.

Passeriformes birds are widely recognized for their remarkable diversity, with over 5700 species described so far. Like most bird species, they possess a karyotype characteristic of modern birds, which includes a bimodal karyotype consisting of a few pairs of macrochromosomes and many pairs of microchromosomes. Although the karyotype is typically 2n = 80, the diploid number can atypically vary greatly, ranging from 56 to approximately 100 chromosomes. In this study, we aimed to understand the extent of conservation of the karyotype’s organizational structure within four species of this group using Bacterial Artificial Chromosomes via Fluorescence In Situ Hybridization (BAC-FISH) with microchromosome probes from Chicken (Gallus gallus) or Zebra Finch (Taeniopygia guttata) per microchromosomes (GGA10-28, except GGA16). By examining the chromosome complement of four passerine species—the Streaked Flycatcher (Myiodynastes maculatus), Shiny Cowbird (Molothrus bonariensis), Southern House Wren (Troglodytes aedon), and Double-collared Seedeater (Sporophila caerulescens)—we discovered a new chromosome number for Southern House Wren. Through FISH experiments, we were able to observe the same pattern of microchromosome organization as in the common ancestor of birds. As a result, we propose a new diploid number for Southern House Wren and confirm the conservation status of microchromosome organization, which may confer evolutionary advantages to this group. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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12 pages, 779 KiB

Open AccessArticle

Seasonal Use of Dairies as Overnight Roosts by Common Starlings (Sturnus vulgaris)

by Callan Lichtenwalter, Karen Steensma, Marcos Marcondes, Kyle Taylor, Craig McConnel and Amber Adams Progar

Birds 2023, 4(2), 213-224; https://doi.org/10.3390/birds4020018 - 2 May 2023

Cited by 1 | Viewed by 2207

Abstract

The Common Starling (Sturnus vulgaris) is an invasive bird species in North America that can cause damage to dairies. Starlings roost in structures on dairies overnight, defecating on cows, feed, and supplies. To target roosts for effective deterrence, farmers must know [...] Read more.

The Common Starling (Sturnus vulgaris) is an invasive bird species in North America that can cause damage to dairies. Starlings roost in structures on dairies overnight, defecating on cows, feed, and supplies. To target roosts for effective deterrence, farmers must know what times of the year starling populations are greatest. To test seasonality, two data sets were analyzed. First, birds were counted for 20–30 min at sunrise and sunset on 10 Whatcom County, Washington dairies over four weeks in September and October of 2016. Starling counts were greater in the last week of observations than in weeks one, two, and three. Second, birds were counted at sunset for four weeks during winter 2021 and spring and summer 2022 at two dairies in the Palouse region of Washington State and Idaho. As temperature and minutes of daylight decreased, bird abundance increased. There was also an effect of season, with more birds counted in winter and spring than in summer. These data sets combined suggest a seasonal use of dairies as night roosts by starlings. With this information, farmers in the United States will know to contact wildlife managers in the summer, so a starling deterrence strategy can be developed before roosts are established in the fall. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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11 pages, 1157 KiB

Open AccessArticle

Stopover Ecology of the European Turtle Dove (Streptopelia turtur), a Threatened Migratory Bird Species, after the Crossing of an Extended Ecological Barrier

by Christos Barboutis, Anastasios Bounas, Elisabeth Navarrete and Thord Fransson

Birds 2023, 4(2), 202-212; https://doi.org/10.3390/birds4020017 - 26 Apr 2023

Cited by 1 | Viewed by 2833

Abstract

Migratory routes, important stopover sites and wintering grounds for the Turtle Dove, a declining trans-Saharan migratory bird, are known mainly for populations in western and central Europe, but very little is known about birds using the eastern migration flyway. By combining long-term ringing [...] Read more.

Migratory routes, important stopover sites and wintering grounds for the Turtle Dove, a declining trans-Saharan migratory bird, are known mainly for populations in western and central Europe, but very little is known about birds using the eastern migration flyway. By combining long-term ringing data, tracking data and citizen science data, a comprehensive picture of the stopover ecology of the Turtle Dove’s spring migration in the eastern Mediterranean is presented. Furthermore, a quantitative estimate of the number of birds that migrate over Greece during the spring migration is given. Approximately 16% of the European population migrates through Greece, passing through as early as the end of March, with the passage lasting up to the end of May. On average, the species arrives depleted after the crossing of the Sahara Desert and the Mediterranean Sea, with no systematic refuelling event taking place in North Africa. Both tracking and ringing data indicate that the birds undergo an extensive stopover after the barrier crossing (as much as close to three weeks). Turtle Doves additionally show significant body mass gain during their stay, indicating the potential importance of stopover sites after the Mediterranean Sea for the conservation of the species. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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12 pages, 1947 KiB

Open AccessArticle

Fruit Color Preference of Frugivorous Birds in an Agroecosystem in Southcentral Mindanao, Philippines

by Navel Kyla B. Balasa, Jirriza O. Roquero, Asraf K. Lidasan, Lothy F. Casim, Angelo Rellama Agduma and Krizler Cejuela Tanalgo

Birds 2023, 4(2), 190-201; https://doi.org/10.3390/birds4020016 - 24 Apr 2023

Cited by 4 | Viewed by 4476

Abstract

The removal of fruit is a consequence of plant–animal interactions, and is a vital step in the natural regeneration cycle of plant populations. This research aimed to determine the effect of fruit color and local landscape on plant–bird interactions in an agroecosystem in [...] Read more.

The removal of fruit is a consequence of plant–animal interactions, and is a vital step in the natural regeneration cycle of plant populations. This research aimed to determine the effect of fruit color and local landscape on plant–bird interactions in an agroecosystem in Southcentral Mindanao, Philippines. We set out 1500 artificial fruit models in ten sampling locations within an agroecosystem. We measured the difference in the proportion of predated/removed (%) fruit models and the risk between sites, fruit color, and predators. Approximately a quarter (24.53%) of the artificial fruit models deployed were predated, and the proportion of predation was significantly higher in the red fruit models (mean = 18.74 ± 9.84) compared to the green fruit models (mean = 11.67 ± 6.17). Birds were the most dominant predators compared to mammals and arthropods, and contributed to at least 60% of the predation of red fruits. Our findings are consistent with previous evidence showing birds’ preferences for darker fruit colors. Although landscape variables did not significantly affect fruit predation, tree cover may help increase these interactions. Overall, our study showed that agroecosystems can still support species of frugivorous birds, as indicated by high fruit predation rates, particularly by birds that can permeate different layers of the agroecosystem. Our findings demonstrate an important implication for habitat quality management within agroecosystems. Enriching agroecosystems with pioneer trees with dark-colored fleshy fruits is a sustainable greening strategy that would benefit frugivores and producers in this system. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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11 pages, 1160 KiB

Open AccessArticle

Arabian Partridge Abundance and Limiting Factors at the Northern Boundary of Its Range

by Alaaeldin Soultan, Moayyed Sher Shah, Ahmed Mohammed Almalki, Stephen Browne and Nico Arcilla

Birds 2023, 4(2), 179-189; https://doi.org/10.3390/birds4020015 - 20 Apr 2023

Cited by 1 | Viewed by 3235

Abstract

The Arabian Partridge (Alectoris melanocephala), is an endemic bird species of the Arabian Desert that lives in groups and inhabits rocky hillsides with patchy vegetation. Throughout their range, Arabian Partridges contend with hunting and habitat destruction, factors that may limit their [...] Read more.

The Arabian Partridge (Alectoris melanocephala), is an endemic bird species of the Arabian Desert that lives in groups and inhabits rocky hillsides with patchy vegetation. Throughout their range, Arabian Partridges contend with hunting and habitat destruction, factors that may limit their distribution and abundance. Although the abundance of this species has been assumed to be stable, no actual estimate of its population size has been undertaken. We assessed the distribution and estimated the abundance of the Arabian Partridge at the northern boundary of its range in Saudi Arabia. The estimated density and abundance of the Arabian Partridge in Harrat Uwayrid Biosphere Reserve was 25.6 (6.16 SE) birds/km² and ~118 individuals, respectively, with higher numbers of individuals in less disturbed sites and near rocky outcrops and hillsides. In sites where hunting occurred, as indicated by the presence of hunting shelters, partridge numbers were extremely low or absent. Our study provides the first quantitative assessment of the Arabian Partridge at the northern limit of its range and highlights the need to reduce threats from hunting, livestock grazing, and feral donkeys and to undertake conservation measures to mitigate factors associated with partridge decline. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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8 pages, 1166 KiB

Open AccessCommunication

Power Laws Govern the Abundance Distribution of Birds by Rank

by Sergio Da Silva and Raul Matsushita

Birds 2023, 4(2), 171-178; https://doi.org/10.3390/birds4020014 - 7 Apr 2023

Cited by 2 | Viewed by 1975

Abstract

Only a few bird species are abundant. Understanding the abundance distribution of bird species is critical for conservation efforts because rare species may be more vulnerable to habitat loss, climate change, and other threats. According to new data, a log left-skewed distribution, rather [...] Read more.

Only a few bird species are abundant. Understanding the abundance distribution of bird species is critical for conservation efforts because rare species may be more vulnerable to habitat loss, climate change, and other threats. According to new data, a log left-skewed distribution, rather than a lognormal distribution, better adjusts to the abundance distribution of bird species. We look at the rank abundance distribution rather than the species abundance distribution that use the same data and find three power laws: for the top four species; for the abundant species minus the top four; and for the rare species. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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12 pages, 1426 KiB

Open AccessArticle

Long-Term Population Trends of House Sparrow and Eurasian Tree Sparrow in Spain

by Elena Ramos-Elvira, Eva Banda, Juan Arizaga, David Martín and José I. Aguirre

Birds 2023, 4(2), 159-170; https://doi.org/10.3390/birds4020013 - 25 Mar 2023

Cited by 3 | Viewed by 3905

Abstract

Urban areas are constantly increasing, which can cause an effect in bird populations since human activities lead to nature alterations. Populations of House Sparrow (Passer domesticus) and Eurasian Tree Sparrow (Passer montanus) have been decreasing in Spain according to [...] Read more.

Urban areas are constantly increasing, which can cause an effect in bird populations since human activities lead to nature alterations. Populations of House Sparrow (Passer domesticus) and Eurasian Tree Sparrow (Passer montanus) have been decreasing in Spain according to the latest national censuses in Spain. In this study, we tried to assess the population trend over more than two decades using ringing data from Spanish constant effort sites, as well as to determine the population and breeding success proxy in relation to habitat composition at landscape level. We analysed the data and confirmed the decreasing trend in the two species. However, Eurasian Tree Sparrow showed signs of increasing presence in urban areas. Furthermore, the productivity remained stable over sampling sites and years, meaning that the causes of the decreasing populations are affecting both adult and juvenile individuals. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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10 pages, 396 KiB

Open AccessArticle

Acoustic Classification of Bird Species Using an Early Fusion of Deep Features

by Jie Xie and Mingying Zhu

Birds 2023, 4(1), 138-147; https://doi.org/10.3390/birds4010011 - 1 Mar 2023

Cited by 7 | Viewed by 3960

Abstract

Bird sound classification plays an important role in large-scale temporal and spatial environmental monitoring. In this paper, we investigate both transfer learning and training from scratch for bird sound classification, where pre-trained models are used as feature extractors. Specifically, deep cascade features are [...] Read more.

Bird sound classification plays an important role in large-scale temporal and spatial environmental monitoring. In this paper, we investigate both transfer learning and training from scratch for bird sound classification, where pre-trained models are used as feature extractors. Specifically, deep cascade features are extracted from various layers of different pre-trained models, which are then fused to classify bird sounds. A multi-view spectrogram is constructed to characterize bird sounds by simply repeating the spectrogram to make it suitable for pre-trained models. Furthermore, both mixup and pitch shift are applied for augmenting bird sounds to improve the classification performance. Experimental classification on 43 bird species using linear SVM indicates that deep cascade features can achieve the highest balanced accuracy of 90.94% ± 1.53%. To further improve the classification performance, an early fusion method is used by combining deep cascaded features extracted from different pre-trained models. The final best classification balanced accuracy is 94.89% ± 1.35%. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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21 pages, 8718 KiB

Open AccessArticle

Activity Patterns, Sex Ratio, and Social Organization of the Bare-Faced Curassow (Crax fasciolata) in the Northern Pantanal, Brazil

by Martin Senič, Karl-L. Schuchmann, Kathrin Burs, Ana Silvia Tissiani, Filipe de Deus and Marinez I. Marques

Birds 2023, 4(1), 117-137; https://doi.org/10.3390/birds4010010 - 20 Feb 2023

Cited by 1 | Viewed by 3135

Abstract

Among Neotropical cracids (Galliformes), many taxa are declining rapidly in population size and facing local extinction. However, in the Brazilian Pantanal, several species occur sympatrically and in abundant numbers to allow for long-term studies. Therefore, the study was intended to collect data and [...] Read more.

Among Neotropical cracids (Galliformes), many taxa are declining rapidly in population size and facing local extinction. However, in the Brazilian Pantanal, several species occur sympatrically and in abundant numbers to allow for long-term studies. Therefore, the study was intended to collect data and statistically evaluate the life history patterns of Bare-faced Curassow (Crax fasciolata), a high-conservation-priority species. Additionally, the effect of applying commonly used independence filters on camera trap data was evaluated. The study was conducted in the SESC Pantanal, Baía das Pedras, Mato Grosso, Brazil, a private protected area of approximately 4200 ha. Between July 2015 and December 2017 (4768 sampling days), 37 sampling locations were monitored with camera traps placed in a regular grid with a spacing of 1 km. Crax fasciolata was detected at 26 (70.27%) of them, with 357 independent captures (554 individuals). Capture success differed among the four seasonal periods, being highest during the receding and lowest during the high-water period. The seasonal difference was more pronounced in the savanna, with significantly lower activity during the rising period and higher activity during the receding period, while it was more uniform in forest-dominated areas. Groups with offspring were more active during the period of receding water, indicating the peak of reproductive activity in the months before. The daily activity of the species followed a bimodal pattern, with peaks between 06:00 and 07:00 and 16:00 and 17:00. Daily activity rhythms were similar when compared between seasonal periods, sexes, and adults with or without offspring and differed between two habitats (more homogeneous in the forest). The mean detected group size was 1.55 ± 0.81 SD, with four animals exhibiting the largest observed aggregation. Larger unisexual aggregations of adults were not observed. The offspring sex ratio was significantly female-skewed at 0.51:1.00, while the adult sex ratio was considered equal at 1.05:1.00 (male:female). The use of different independence filters did not alter the BFC general activity pattern estimates. Cracids can be considered important bioindicators of habitat quality. The results of this study outline the importance of the Pantanal as a stronghold for this species and the privately protected areas with low anthropogenic activity as highly beneficial to its populations. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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14 pages, 2425 KiB

Open AccessArticle

Avifaunal Diversity and Abundance in the Proposed Sarasalai Mangrove Reserve, Jaffna, Sri Lanka

by Nitharsan Aloysius, Shashi Madhushanka and Chathuri Chandrika

Birds 2023, 4(1), 103-116; https://doi.org/10.3390/birds4010009 - 17 Feb 2023

Cited by 1 | Viewed by 5446

Abstract

Mangrove ecosystems are excellent habitats for migrating and resident birds. The proposed Sarasalai mangrove reserve is located in one of the richest waterbird zones in Sri Lanka. This site has never been properly studied as a single site for its avifaunal diversity. Hence, [...] Read more.

Mangrove ecosystems are excellent habitats for migrating and resident birds. The proposed Sarasalai mangrove reserve is located in one of the richest waterbird zones in Sri Lanka. This site has never been properly studied as a single site for its avifaunal diversity. Hence, the present study aims to find avifaunal diversity in the Sarasalai mangrove. Data collection was performed from April to December 2021. Eight permanent sampling stations were demarcated along the existing roads and were visited twice a month to collect bird abundance data. A total of 107 bird species belonging to 45 families including 58 waterbird species were recorded in the present study. Bird abundance did not significantly differ among the eight studied sites. Studied sites with the availability of water and good tree cover had the highest Shannon Diversity Index. The mangrove vegetation, with tall grasses, and the high water level were significant factors for bird abundance in some sites. Monthly bird abundance showed a notable increase during the migratory months. Among the recorded bird species, Greater Flamingos showed the highest abundance. Moreover, some rare waterbirds including Indian Spot-billed Duck and Glossy Ibis were commonly recorded. Several putative threats have been recorded during this study, namely unplanned land encroachments, bird hunting, and clearing of mangroves. Although this site has a high value in providing a healthy habitat for many wetland birds, it is yet to be declared a protected area. The lack of a clear boundary and a governing body to protect this area exacerbates its protection issues. Hence, it is proposed that immediate legal actions must be taken to declare this important migratory bird area a mangrove forest reserve. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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16 pages, 1656 KiB

Open AccessArticle

Flight Type and Seasonal Movements Are Important Predictors for Avian Collisions in Wind Farms

by Alfonso Balmori-de la Puente and Alfonso Balmori

Birds 2023, 4(1), 85-100; https://doi.org/10.3390/birds4010007 - 9 Feb 2023

Cited by 3 | Viewed by 4311

Abstract

Wind farms are an alternative energy source mitigating environmental pollution. However, they can have adverse effects, causing an increase in mortality for wildlife through collision with wind turbines. The aim of this study was to investigate the risks of bird collisions with wind [...] Read more.

Wind farms are an alternative energy source mitigating environmental pollution. However, they can have adverse effects, causing an increase in mortality for wildlife through collision with wind turbines. The aim of this study was to investigate the risks of bird collisions with wind turbines linked to species-specific variables. For this purpose, we have analysed the dead birds involved in wind farm collisions that were admitted to two rescue centres in Spain over a period of 16 years (2001–2016; full dataset: n = 3130). All the birds analysed in this study were killed by turbines in wind farms. We performed two linear models using all species and a reduced dataset (bird of prey and passerine having more than four collisions) that included group, seasonal movements, flight type, length, and the number of pairs for the Spanish and European populations. The coefficients and the percent of variance explained by each relevant variable were determined in the models and the real values were compared with predicted values to visualise the goodness of fit. We found that the flight type was the most important variable explaining 35% of the total variability for the model including all species and 29% for the reduced dataset respectively, followed by seasonal movement type (4%/17% respectively) and the Spanish population (4%/6%). Subsequent analyses suggested that species with hovering, song-flights and active soaring flights are more susceptible to collisions with wind farms, and that species showing partial migration have a significant peak of collisions across spring and autumn. The estimated species-specific collision index can help in modelling the theoretical risk of collision with wind turbines, depending on the species existing in the area and their predicted values of vulnerability, which is linked to flight types and seasonal movements. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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12 pages, 983 KiB

Open AccessArticle

Susceptibility to Predation Varies with Body Mass, Foraging Niche, and Anti-Predator Responses among Bird Species

by Guy Beauchamp

Birds 2023, 4(1), 73-84; https://doi.org/10.3390/birds4010006 - 5 Feb 2023

Cited by 9 | Viewed by 3205

Abstract

Predation is a major source of mortality for many avian species. Species that face more predators, and those with less effective anti-predator responses, are presumably more likely to die from predation over time. Predation rate, as a measure of susceptibility to predation, is [...] Read more.

Predation is a major source of mortality for many avian species. Species that face more predators, and those with less effective anti-predator responses, are presumably more likely to die from predation over time. Predation rate, as a measure of susceptibility to predation, is difficult to measure in the field. Radio-tracking studies, however, allow researchers to determine the time and cause of death of marked individuals, making it possible to estimate predation rate. I used estimates of predation rates from a large number of published radio-tracking studies in birds to assess in a phylogenetic framework the effect of several potential determinants. I obtained 393 estimates of predation rates from 129 species. Predation rates were lower in areas with fewer predators, such as islands and aquatic habitats, and for species with fewer potential predators, such as larger species. The predation rate was also lower for prey species with effective anti-predator responses, such as those that forage in flocks. Radio-tracking studies provide a unique opportunity to estimate overall predation rate in the field. Broadening the range of species and the range of habitats involved in such studies will help to further elucidate the factors that affect susceptibility to predation. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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12 pages, 1372 KiB

Open AccessArticle

Using Acoustic Data Repositories to Study Vocal Responses to Playback in a Neotropical Songbird

by Pietra Oliveira Guimarães, Letícia Campos Guimarães, Renato Rodrigues Oliveira, Fernando Almeida and Pedro Diniz

Birds 2023, 4(1), 61-72; https://doi.org/10.3390/birds4010005 - 4 Feb 2023

Viewed by 2811

Abstract

Birds may alter song structure in response to territorial challenges to convey information about aggressive intent or fighting ability. Professional and amateur ornithologists upload daily many birdsong recordings into acoustic data repositories, usually scoring whether songs were recorded in response to a conspecific [...] Read more.

Birds may alter song structure in response to territorial challenges to convey information about aggressive intent or fighting ability. Professional and amateur ornithologists upload daily many birdsong recordings into acoustic data repositories, usually scoring whether songs were recorded in response to a conspecific playback or produced spontaneously. We analyzed recordings from these repositories to evaluate if song traits of Rufous-browed Peppershrikes (Cyclarhis gujanensis) vary between playback-elicited songs and spontaneous songs. For each recording after playback, we chose one spatially closer spontaneous recording to avoid geographic bias. Birds recorded after playback produced slightly longer songs than birds that were singing spontaneously. This result was accounted for by increases in the amount of sound and silence within a song after the playback instead of changes in the mean number or duration of elements. Playback did not alter song frequency parameters (bandwidth, minimum, mean, and maximum frequencies) or song rate. These results indicate that song duration might mediate aggressive interactions in Rufous-browed Peppershrikes. Even considering limitations such as unknown playback stimulus identity and possible pseudoreplication, acoustic data repositories give a unique yet unexplored opportunity to gather insights into the evolution of song flexibility during aggressive encounters. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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15 pages, 5986 KiB

Open AccessArticle

Status of the Pallas’s Gull Ichthyaetus ichthyaetus during Summer/Autumn in the Fairway Volga–Kama Reservoirs (East European Plain) in Russia

by Sergey Golubev

Birds 2023, 4(1), 46-60; https://doi.org/10.3390/birds4010004 - 31 Jan 2023

Cited by 2 | Viewed by 1686

Abstract

The Pallas’s Gull Ichthyaetus ichthyaetus is a fish-eating predator listed in the category of recovering species of the Red Book of the Russian Federation. The purpose of the research was to study the state of the Pallasʹs Gull in the fairway (navigable zone) [...] Read more.

The Pallas’s Gull Ichthyaetus ichthyaetus is a fish-eating predator listed in the category of recovering species of the Red Book of the Russian Federation. The purpose of the research was to study the state of the Pallasʹs Gull in the fairway (navigable zone) of the Volga–Kama reservoirs, in Russia and to assess their role in the current distribution of the species. In the summer and autumn of 2020–2022, at 11 reservoirs of the Volga and Kama rivers, counts of Pallasʹs Gulls were carried out from the bow deck of the R/V Akademik Topchiev. The transect length was 4633.5 km; the duration of observations was 364.3 h. A comprehensive bird count was applied in the direction of the vessel’s movement on transects with a fixed counting strip width of 200 m (100 m in each direction from the bow of the vessel). Birds were usually fixed on 30-min transects. The Pallas’s Gulls were found in 7 of the 11 reservoirs studied, and their status varied between common and very rare. The species was more abundant in the Gorky reservoir than in the Cheboksary, Kuibyshev, Saratov, and Nizhnekamsk reservoirs. The smallest abundance was recorded in the Volgograd and Rybinsk reservoirs. The Pallas’s Gull shows a steady annual presence on most reservoirs. The results indicate that in the Volga Basin, the range of Pallas’s Gull has expanded further north by more than 1000 km over the past 30 years from the species’ original areas of sustainable breeding in the North Caspian. Adult individuals of the Pallasʹs Gull (83.4% of the age composition of the population) play the main role in the dispersal. The most favorable clusters of the stable presence of the species were lake-shaped fragments of the Gorky and Kuibyshev reservoirs. On the territory of the East European Plain, the Volga–Kama reservoirs are important, if not decisive, in expanding the range of Pallas’s Gull to the north. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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13 pages, 1056 KiB

Open AccessArticle

Urban Birds Using Insects on Front Panels of Cars

by Jukka Jokimäki and Marja-Liisa Kaisanlahti-Jokimäki

Birds 2023, 4(1), 15-27; https://doi.org/10.3390/birds4010002 - 19 Jan 2023

Cited by 2 | Viewed by 3408

Abstract

Urbanization influences the food availability and quality for birds in many ways. Although a great amount of food for birds is provided incidentally or intentionally in urban areas, the quantity of insect-based food can be reduced in cities. We studied the role of [...] Read more.

Urbanization influences the food availability and quality for birds in many ways. Although a great amount of food for birds is provided incidentally or intentionally in urban areas, the quantity of insect-based food can be reduced in cities. We studied the role of one artificial food source, insects smashed on the front panels of cars, in Finland, and more specifically in the city of Rovaniemi, by conducting questionnaire research, searching for data from databases and performing a field study. Our results indicated that a total of seven bird species have been detected using insects on the front panels of cars in Finland. However, this behavior is not yet common since about 60% of responders to the questionnaire stated that this behavior is currently either rare or very rare. Most of the observations identified House Sparrows, followed by the White Wagtail or the Eurasian Jackdaw. Only a few observations identified the Eurasian Tree Sparrow, the Hooded Crow, the Great Tit and the Eurasian Magpie. The phenomenon was distributed quite widely across Finland, except in the case of the Eurasian Jackdaws, for which observations were restricted only to the southern part of the country. The first observation was made about the House Sparrow in 1971, followed by the White Wagtail (1975), Hooded Crow (1997), Eurasian Jackdaw (2006), Eurasian Tree Sparrow (2011), Eurasian Magpie (2019) and Great Tit (2022). The species using this food source are mainly sedentary urban exploiters, such as corvids and sparrows, that have been previously reported to have several different types of innovative behaviors. Most of the observations were conducted in urban parking sites of hypermarkets, and no observations were made in residential areas. Most of the foraging observations were made during the end phase of the breeding season, partly supporting the extra need for high-quality insect-based food for nestlings and fledglings. Our observations indicate that this behavior is not yet common and widespread among species. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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14 pages, 1814 KiB

Open AccessArticle

When to Return to Normal? Temporal Dynamics of Vigilance in Four Situations

by Claudia Mettke-Hofmann

Birds 2023, 4(1), 1-14; https://doi.org/10.3390/birds4010001 - 22 Dec 2022

Cited by 3 | Viewed by 2082

Abstract

Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how [...] Read more.

Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how animals perceive a situation and the potential mechanism used to deal with it. I investigated the time course of vigilance in Gouldian Finches in four situations (familiar environment, two changed environments–novel object at a neutral location (exploration trial) or above the feeder (neophobia trial), novel environment). The frequency of head movements was assessed in four consecutive 15-min blocks in same sex pairs with a high frequency generally seen as indicative of high vigilance. Vigilance decreased over time in the familiar situation indicating vigilance decrement with a similar time course in the exploration trial. Vigilance was consistently high in the neophobia trial and only returned to normal in the last block. Finally, vigilance plummeted in the novel environment and did not return to normal within an hour. Results suggest that perceived threats affected vigilance and that information gathering reduced uncertainty allowing vigilance to return to normal levels but with different time courses depending on the situation. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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8 pages, 1085 KiB

Open AccessArticle

Discriminant Criteria for Field Sexing in the Eurasian Tree Sparrow by Combining Body Size and Plumage Features

by Sergio González, Francisco Morinha, Diego Villanúa, Lander Goñi and Guillermo Blanco

Birds 2022, 3(4), 402-409; https://doi.org/10.3390/birds3040027 - 29 Nov 2022

Cited by 1 | Viewed by 3168

Abstract

The Eurasian tree sparrow (Passer montanus) is a monomorphic passerine, for which it is impossible to differentiate between males and females based on external characteristics. Being a species frequently captured for ringing, having a reliable method to determine sex from conventional [...] Read more.

The Eurasian tree sparrow (Passer montanus) is a monomorphic passerine, for which it is impossible to differentiate between males and females based on external characteristics. Being a species frequently captured for ringing, having a reliable method to determine sex from conventional biometric measurements would facilitate its study and be very useful for the correct management and conservation of this declining species. In the present study, we used biometric measurements recorded in 66 individuals captured with mist nets in communal roosts in northern Spain during the winter and sexed them using molecular techniques. We conducted a discriminant function analysis (DFA) to derive equations that allowed us to determine the sex of the specimens from some of the measurements recorded in the field. Significant differences were found between males and females in wing length, third primary length, badge width and height and body weight. The DFA provided two functions that correctly classified the sex of 94.7% of the individuals using wing length and badge width, and 98.2% if weight was added to the analysis. Our results allow sexing from measurements that can be easily recorded in the field with the tools commonly used in banding sessions and without the need for additional training. Considerations of Bergmann’s and Allen’s rules on body size and the use of DFA in different populations are discussed. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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19 pages, 3485 KiB

Open AccessArticle

Bird Assemblages in a Peri-Urban Landscape in Eastern India

by Ratnesh Karjee, Himanshu Shekhar Palei, Abhijit Konwar, Anshuman Gogoi and Rabindra Kumar Mishra

Birds 2022, 3(4), 383-401; https://doi.org/10.3390/birds3040026 - 18 Nov 2022

Cited by 2 | Viewed by 3315

Abstract

Urbanization plays an important role in biodiversity loss across the globe due to natural habitat loss in the form of landscape conversion and habitat fragmentation on which species depend. To study the bird diversity in the peri-urban landscape, we surveyed four habitats—residential areas, [...] Read more.

Urbanization plays an important role in biodiversity loss across the globe due to natural habitat loss in the form of landscape conversion and habitat fragmentation on which species depend. To study the bird diversity in the peri-urban landscape, we surveyed four habitats—residential areas, cropland, water bodies, and sal forest; three seasons—monsoon, winter, and summer in Baripada, Odisha, India. We surveyed from February 2018 to January 2019 using point counts set along line transects; 8 transects were established with a replication of 18 each. During the survey, 6963 individuals of 117 bird species belonged to 48 families and 98 genera in the study area, whereas cropland showed rich avian diversity. Based on the non-parametric multidimensional scale (NMDS) and one-way ANOVA, bird richness and abundance differed significantly among the habitats. Cropland showed higher species richness than other habitats; however, water bodies showed more abundance than others. The similarity of bird assemblage was greater between residential areas and cropland than forest and water bodies based on similarity indices. Among seasons, we observed the highest bird species richness in winter and the highest similarity of species richness in monsoon and summer. In conclusion, our study reported that agricultural and degraded landscapes like cropland play important roles in conserving bird diversity in peri-urban landscapes. Our findings highlighted and identified the problems that affect the local biodiversity (e.g., birds) in the peri-urban landscape. It can assist the local government in urban planning and habitat management without affecting the local biodiversity, including birds. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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9 pages, 5892 KiB

Open AccessCommunication

Observation of an Attempted Forced Copulation within a Captive Flock of Greater Flamingos (Phoenicopterus roseus)

by Paul Rose

Birds 2022, 3(4), 374-382; https://doi.org/10.3390/birds3040025 - 15 Nov 2022

Cited by 1 | Viewed by 2844

Abstract

Flamingos (Phoenicopteriformes) are obligate colonial species that nest in large colonies, with monogamous pairs rearing a single chick following a synchronised group courtship display. Within this relatively simplistic behavioural description, deviations from these social and reproductive norms are apparent. Same sex pairings, multi-bird [...] Read more.

Flamingos (Phoenicopteriformes) are obligate colonial species that nest in large colonies, with monogamous pairs rearing a single chick following a synchronised group courtship display. Within this relatively simplistic behavioural description, deviations from these social and reproductive norms are apparent. Same sex pairings, multi-bird relationships and extra pair copulations are documented in the literature. Flamingos display highly sexually selected characteristics of plumage colour, carotenoid accumulation and diversity of display movements that underpin mate choice decisions. The brightest birds in best body condition are more successful at breeding. Therefore, documented mate guarding of female birds by male partners, is a relevant response to maximise investment in a pair bond. Limited information that describes the action of forced copulation by the male flamingo and the response of the female bird is available in the literature. This paper describes an occurrence of an attempted forced copulation by an older male Greater Flamingo to a younger female bird. Such behaviour may be an artefact of the captive environment, and limited mate choice when compared to the sizes of wild flocks, or it could be regularly apparent in the wild and therefore worthy of more scrutiny and empirical study. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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21 pages, 7730 KiB

Open AccessArticle

Bird Communities and the Rehabilitation of Al Karaana Lagoons in Qatar

by Ayaterahman Draidia, Momina Tareen, Nuran Bayraktar, Emily R. A. Cramer and Kuei-Chiu Chen

Birds 2022, 3(4), 320-340; https://doi.org/10.3390/birds3040022 - 27 Sep 2022

Viewed by 2616

Abstract

Qatar, a peninsular country in the Persian Gulf, is significant to avian species due to its location along the African–Eurasian Flyway, a key migratory path. Receiving untreated domestic and industrial liquid waste from Qatar in the past, Al Karaana Lagoons have since been [...] Read more.

Qatar, a peninsular country in the Persian Gulf, is significant to avian species due to its location along the African–Eurasian Flyway, a key migratory path. Receiving untreated domestic and industrial liquid waste from Qatar in the past, Al Karaana Lagoons have since been reconstructed as an artificial wetland to address the growing environmental concern posed by contamination build-up. This study documents the changes in biodiversity at Al Karaana Lagoons following their environmental remediation. Data collected (2015 and 2017) by Ashghal (Public Works Authority) prior to project implementation was analyzed alongside data collected independently following project completion (2019–2021). There was a marked increase in bird biodiversity following remediation, including substantial use by migratory species and resident breeders. Further analysis of water quality data of the TSE (treated sewage effluent) ponds shows that they are eutrophic but still support substantial bird life. The project’s success demonstrates how reclaimed lands can provide important habitats to local and migratory birds and encourages similar restoration efforts in the future in both Qatar and elsewhere. We call for the continued monitoring of the site and the implementation of guidelines for the use of the site that balance human activities and habitat quality. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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13 pages, 1021 KiB

Open AccessCommunication

Home Ranges and Migration Routes of Four Threatened Raptors in Central Asia: Preliminary Results

by Mohan Ram, Aradhana Sahu, Shyamal Tikadar, Devesh Gadhavi, Tahir Ali Rather, Lahar Jhala and Yashpal Zala

Birds 2022, 3(3), 293-305; https://doi.org/10.3390/birds3030020 - 14 Sep 2022

Cited by 1 | Viewed by 4390

Abstract

Understanding the migratory route of raptors in their breeding and wintering grounds is crucial for ensuring their effective conservation. This study presents the preliminary findings through satellite telemetry to describe the summer and winter home ranges, movement ecology, activity, and migration routes of [...] Read more.

Understanding the migratory route of raptors in their breeding and wintering grounds is crucial for ensuring their effective conservation. This study presents the preliminary findings through satellite telemetry to describe the summer and winter home ranges, movement ecology, activity, and migration routes of single individuals of Greater Spotted Eagle (Clanga clanga), Indian Spotted Eagle (Clanga hastata), Tawny Eagle (Aquila rapax), and Pallid Harrier (Circus macrourus). We calculated the home ranges as the minimum convex polygons (MCPs) and kernel utilisation distributions (KUD). Pallid Harrier had the smallest home range size of 4.29 km² (95% MCP) and 3.98 km² (95% KUD) in its breeding ground located in Russia, while the Greater Spotted Eagle had the largest home range size of 9331.71 km² (95% MCP) and 5991.15 km² (95% KUD) in Kazakhstan. The monthly and daily distances covered by tagged birds were significantly higher during migration. Our study also reports the first record of the winter and summer home range of the Indian Spotted Eagle in Pakistan. The tagged raptor used low elevation flyways than the straighter northern flyways over the Himalayan Mountain range, as found in another earlier study. Our study is the foremost satellite telemetry attempt from the region, highlighting important aspects of the migration route of migratory raptors to India. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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8 pages, 1794 KiB

Open AccessCommunication

Chick Provisioning in Grey-Faced Petrel (Pterodroma gouldi) under Environmental Stress

by James C. Russell, Jemma R. Welch, Rob Dunn and Karen Bourgeois

Birds 2022, 3(3), 285-292; https://doi.org/10.3390/birds3030019 - 10 Sep 2022

Viewed by 2023

Abstract

Grey-faced Petrels (Pterodroma gouldi) are colonial burrowing seabirds predominantly nesting on offshore islands of the upper North Island of New Zealand. We studied their chick provisioning on Te Hāwere-a-Maki during two years of unfavourable warmer La Niña conditions in 2011 and [...] Read more.

Grey-faced Petrels (Pterodroma gouldi) are colonial burrowing seabirds predominantly nesting on offshore islands of the upper North Island of New Zealand. We studied their chick provisioning on Te Hāwere-a-Maki during two years of unfavourable warmer La Niña conditions in 2011 and 2013. We intensively monitored chicks in each year, weighing chicks every 12 h for 10 consecutive days to estimate meal sizes following chick provisioning and to estimate 12-hourly body mass loss as a function of time since last feeding. We found a quadratic relationship of body mass loss with time since last feeding, with rapid digestion of meals following provisioning followed by a period of fasting from five days post feeding as chicks waited an unknown and variable amount of time until their next meal. The rate of body mass loss did not depend on chick age nor body mass, and did not differ between years, but heavier chicks included in our study were more likely to successfully fledge, suggesting a legacy of adult provisioning prior to our study commencing. Our regular handling of chicks for monitoring has no discernible impact on parent provisioning compared to a set of control chicks. The mean estimates of 100-gram meal sizes and 10-day foraging trip durations are likely to be below the break-even point for this species. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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8 pages, 2196 KiB

Open AccessCommunication

A Local Approach to Better Understand the Spread and Population Growth of the Monk Parakeet as an Invasive Species

by Sandro López-Ramírez and Antonio-Román Muñoz

Birds 2022, 3(3), 277-284; https://doi.org/10.3390/birds3030018 - 2 Sep 2022

Cited by 4 | Viewed by 2344

Abstract

Invasive exotic species are currently a topic of interest for environmental management agencies and the media. This is due to the socio-economic and environmental problems that they are causing or may cause. The Monk Parakeet is a clear example of this, especially in [...] Read more.

Invasive exotic species are currently a topic of interest for environmental management agencies and the media. This is due to the socio-economic and environmental problems that they are causing or may cause. The Monk Parakeet is a clear example of this, especially in some large cities, where populations are growing quickly, and their distribution continues to expand. In our study, we focused on a population that has been closely monitored during the last 25 years to understand its growth and change on a local scale to determine the maximum sustainable population size in the invaded area and to check when this population began to act as a source of new breeding colonies to adjacent areas. The first breeding of the species occurred in 2002, and from then, the average growth rate (r) of the population was 0.191 until 2016, when it stabilized and declined slightly (r = −0.043). The maximum growth rate occurred during the years 2002 and 2007 and was 0.314. The results obtained give us information about the carrying capacity of the study area, allowing us to explain the dispersal process of the species to neighbouring areas, with populations that have reached maximum size serving as sources of individuals dispersing to suitable areas. In our study area, the species shows a strong preference for building its nests in palm trees and electric utility structures. Our study’s local focus on studying the population dynamics of an invasive species may allow us to understand the increased range of the species on a larger scale, which is necessary in order to be able to design appropriate and effective management strategies. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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17 pages, 2490 KiB

Open AccessArticle

Assessing the Uncertainty of Total Seabird Bycatch Estimates Synthesized from Multiple Sources with a Scenario Analysis from the Western and Central Pacific

by Can Zhou and Baochao Liao

Birds 2022, 3(3), 260-276; https://doi.org/10.3390/birds3030017 - 10 Aug 2022

Cited by 1 | Viewed by 2145

Abstract

Each year, billions of seabirds undertake migrations, connecting remote regions of the world, potentially synchronizing population fluctuations among distant areas. This connectedness has implications for the uncertainty calculations of the total seabird bycatch estimate at a regional/global scale. Globally, fisheries bycatch poses a [...] Read more.

Each year, billions of seabirds undertake migrations, connecting remote regions of the world, potentially synchronizing population fluctuations among distant areas. This connectedness has implications for the uncertainty calculations of the total seabird bycatch estimate at a regional/global scale. Globally, fisheries bycatch poses a major problem in fishery management, and estimating the uncertainty associated with a regional/global seabird bycatch estimate is important because it characterizes the accuracy and reliability of the fisheries’ impact on the seabird populations. In this study, we evaluate different assumptions underlying the estimation of the variability of the total seabird bycatch at a regional/global scale based on local assessment reports. In addition to theoretical analysis, we also simulate multiple spatially distant separately managed areas with relatively low levels of observer coverage, based on bycatch data from the Western and Central Pacific Fisheries Commission convention area. The results show that assuming a completely synchronized variation produced the most conservative uncertainty estimate and it also missed an opportunity to improve the precision. Simplified correlation structures also failed to capture the complex dynamics of bycatch rates among spatially distant areas. It is recommended to empirically estimate the correlation of bycatch rates between each pair of sources based on bycatch rate time series. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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Review

Jump to: Research, Other

13 pages, 1485 KiB

Open AccessReview

Current Knowledge of Helminths of Wild Birds in Ecuador

by Patricio D. Carrera-Játiva and Gustavo Jiménez-Uzcátegui

Birds 2024, 5(1), 102-114; https://doi.org/10.3390/birds5010007 - 2 Feb 2024

Viewed by 1675

Abstract

Parasitic helminths are diverse in wild birds globally, but knowledge about helminths in Ecuadorian avifauna is still fragmentary. In the present review, records about helminths (Platyhelminthes, Nematoda, and Acanthocephala) in Ecuadorian wild birds is presented. A systematic search was carried out using the [...] Read more.

Parasitic helminths are diverse in wild birds globally, but knowledge about helminths in Ecuadorian avifauna is still fragmentary. In the present review, records about helminths (Platyhelminthes, Nematoda, and Acanthocephala) in Ecuadorian wild birds is presented. A systematic search was carried out using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guideline to compile and summarize the available literature on helminths in wild birds in Ecuador. Data were obtained from ten scientific articles, eight undergraduate theses, and one doctoral dissertation, published between 1966 to 2022. Forty helminth taxa were recorded and information about the host species, site of infection, and location are provided. Nematodes of the genus Ascaridia Dujardin, 1844 were the helminth taxa with the greatest number of records in birds, parasitizing 16 avian species. Also, the Rock Dove (Columba livia; Gmelin, 1789) was the avian species with the greater number of helminth records (n = 11). This review serves as a compendium for future ecological and epidemiological studies on helminths in wild birds in Ecuador and South America. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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Other

Jump to: Research, Review

17 pages, 2606 KiB

Open AccessPerspective

Ten Principles for Bird-Friendly Forestry: Conservation Approaches in Natural Forests Used for Timber Production

by Nico Arcilla and Māris Strazds

Birds 2023, 4(2), 245-261; https://doi.org/10.3390/birds4020021 - 16 Jun 2023

Cited by 5 | Viewed by 4846

Abstract

Bird–forestry relationships have been the subject of research and conservation initiatives for decades, but there are few reviews of resulting recommendations for use by forest managers. We define “bird-friendly forestry” as forest management that applies recommendations from research seeking to reconcile logging with [...] Read more.

Bird–forestry relationships have been the subject of research and conservation initiatives for decades, but there are few reviews of resulting recommendations for use by forest managers. We define “bird-friendly forestry” as forest management that applies recommendations from research seeking to reconcile logging with bird conservation in natural forests used for timber production. We reviewed relevant studies to synthesize 10 principles of bird-friendly forestry: (1) protect and enhance vertical structure through uneven-aged silviculture; (2) leave abundant dead wood in different decay stages; (3) maintain residual large green trees; (4) create and maintain sufficient amounts of uncut reserves and corridors; (5) maximize forest interior by retaining large contiguous forest tracts in landscapes with sufficient functional connectivity; (6) maintain buffers along streams, rivers, and wetlands cultural and urban landscapes; (7) maintain horizontal stand structure and enhance vegetation diversity by creating canopy gaps; (8) extend the temporal scale of logging cycles; (9) minimize post-logging disturbance to forests, particularly during the bird breeding season; and (10) manage for focal species and guilds. These principles may serve as guidelines in developing bird-friendly management plans customized for regional priority species, with a clearly articulated vision and quantitative objectives through which success can be measured. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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11 pages, 721 KiB

Open AccessBrief Report

Concentrations of Manganese in Tufted Titmouse Feathers near Metal Processing Plants

by Rachael Sarnowski and James S. Kellam

Birds 2023, 4(1), 148-158; https://doi.org/10.3390/birds4010012 - 22 Mar 2023

Cited by 1 | Viewed by 4156

Abstract

Human industry and land use has led to the anthropogenic release of manganese (Mn) into the air and soil near manufacturing centers. Overexposure to Mn can cause considerable health problems in birds. We studied whether the concentration of Mn in bird feathers correlates [...] Read more.

Human industry and land use has led to the anthropogenic release of manganese (Mn) into the air and soil near manufacturing centers. Overexposure to Mn can cause considerable health problems in birds. We studied whether the concentration of Mn in bird feathers correlates with the distance to point sources of Mn air emissions. Feathers were collected from Tufted Titmice (Baeolophus bicolor) at two sites in western Pennsylvania, USA. One site was in proximity (0.3 km) to a steel plant with documented Mn releases, and the other site was in a different town about 4.0 km away from other steel plants with documented Mn releases. Using the microwave plasma–atomic emission spectrometer (MP–AES), we found that tail feathers collected from nearest to a steel plant had a significantly higher concentration of Mn compared to the samples from the site further from the emission source. A body mass index was calculated for each set of birds; however, the indices did not vary significantly. This is the first published study of Mn sequestration in Tufted Titmouse feathers. This study develops our general understanding of the potential use of bird feathers as non-invasive bioindicators of environmental metal exposure. Full article

(This article belongs to the Special Issue Feature Papers of Birds 2022–2023)

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