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16 pages, 3478 KiB

Open AccessArticle

The Population Density, Interspecific Territoriality, and Philopatry of Shrikes (Laniidae) and Bushshrikes (Malaconotidae) in a Mosaic of Natural and Human-Modified Acacia Savanna

by Grzegorz Kopij

Biology 2025, 14(5), 577; https://doi.org/10.3390/biology14050577 - 20 May 2025

Abstract

In avian behavioural and spatial ecology, issues related to population density, territoriality, and philopatry are especially important. These are often interrelated. The aim of this study was to analyse these behaviours in shrikes inhabiting an acacia savanna in northern Namibia (400 ha). Population [...] Read more.

In avian behavioural and spatial ecology, issues related to population density, territoriality, and philopatry are especially important. These are often interrelated. The aim of this study was to analyse these behaviours in shrikes inhabiting an acacia savanna in northern Namibia (400 ha). Population densities of one shrike and four bushshrike species were studied by means of the territory mapping method. About half of the study area had been modified by humans into cultivated fields, orchards, sport fields, and human settlements. This study was conducted in 2012/2013, 2017/2018, and 2019/2020. The most common species were the Black-backed Puffback (2.5 pairs/100 ha) and Crimson-breasted Shrike (1.9); the least common were the Southern White-crowned Shrike (0.8) and Brubru (1.0). Statistics for the Brown-crowned Tchagra indicated a density of 1.5 pairs/100 ha. While the density of the Brown-crowned Tchagra and Brubru remained stable over the years, the population densities of the Black-backed Shrike, Crimson-breasted Shrike, and Southern White-crowned Shrike showed a remarkable increase over the years 2012–2020. All bushshrike species showed a preference for patches of natural savanna vegetation. This was especially evident in the Crimson-breasted Shrike and the Brubru. However, the Southern White-crowned Shrike from the shrike family did not show this preference. The presented studies showed marked interspecific differences in territoriality and philopatry. Furthermore, even within the same species, marked temporal differences were shown in population density, probably also in philopatry. Within families, these behaviours may shape both resource competition and mate competition, while between families, these behaviours only shape resource competition. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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22 pages, 5254 KiB

Open AccessArticle

Modeling the Impact of Ecological Restoration on Waterbird Diversity and Habitat Quality in Myanmar’s Moe Yun Gyi Wetland

by Phyoe Marnn, Haider Ali, Haibo Jiang, Yang Liu, Ziqi Li, Sarfraz Ahmed, Tao Yang, Ziwei Li and Chunguang He

Biology 2025, 14(5), 519; https://doi.org/10.3390/biology14050519 - 8 May 2025

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Abstract

The Moe Yun Gyi constructed wetland in Myanmar, located along the East Asian–Australian bird migration path, serves as a crucial habitat for migrating waterbirds. Protecting this biodiverse habitat is crucial in the face of ongoing threats, highlighting the need for effective conservation strategies. [...] Read more.

The Moe Yun Gyi constructed wetland in Myanmar, located along the East Asian–Australian bird migration path, serves as a crucial habitat for migrating waterbirds. Protecting this biodiverse habitat is crucial in the face of ongoing threats, highlighting the need for effective conservation strategies. This study aims to evaluate the effects of the restoration on the populations of waterbirds from January 2014 to January 2024, by analyzing the composition and the spatiotemporal dynamics of waterbirds communities, with particular reference to changes in diversity. We measured waterbird quantity and species richness using the point count method, employing the Shannon-Wiener and D_G–F Index formulae for diversity analysis. Habitat analysis was conducted with ArcGIS 10.6 and eCognition 10.3, while data analysis utilized RStudio and Microsoft Excel. The results indicate that restoration efforts in 2016 initially led to a decline in waterbird populations. Restoration efforts after 2017 resulted in a twofold increase in both diversity and abundance. However, in 2023, flooding in Bago City caused a decline in waterbird populations, impacting habitat rehabilitation. There was a notable rise in uncommon waterbird populations, especially threatened Pelecaniformes. The community’s richness has partially recovered, but seasonal water level volatility continues to impact diversity. The application of restoration techniques directly alters the extent and depth of water bodies, which are essential parameters for supporting appropriate waterbird habitats. We propose implementing a rational system for managing water levels, optimizing wetland hydrology, and enhancing water level regulation to safeguard significant resting areas along migration paths. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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13 pages, 1099 KiB

Open AccessCommunication

Feathers of Grace: The “After You” Gesture in Japanese Tits

by Sergio Da Silva and Raul Matsushita

Biology 2025, 14(3), 297; https://doi.org/10.3390/biology14030297 - 16 Mar 2025

Viewed by 557

Abstract

A recent study found evidence of symbolic gesture use in Japanese tits (Parus minor). The study reveals how these birds use wing-fluttering movements to transmit an “after you” directive to their partners, implying a degree of cognitive skill previously thought to [...] Read more.

A recent study found evidence of symbolic gesture use in Japanese tits (Parus minor). The study reveals how these birds use wing-fluttering movements to transmit an “after you” directive to their partners, implying a degree of cognitive skill previously thought to be unique to humans and great apes. If confirmed, this research contradicts long-held notions about animal communication by proving that Japanese tits not only participate in intricate vocal communications, which can comprise phrases with specific grammatical rules, but also use body language as a form of engagement. Here, we evaluate this claim by inspecting the data and utilizing bootstrapping to expand the sample size. We find a large variation in how frequently the “after you” gesture is employed in different bootstrap samples, suggesting that while the gesture is a consistent behavior, its frequency can vary significantly. Moreover, the timing of the male’s response to the female’s gesture can fluctuate, though the response itself appears to be a stable phenomenon. Beyond evaluating the bootstrapping technique, we employ causal inference to examine whether wing fluttering by female Japanese tits leads to a quicker response by males, entering the nest more swiftly. The analysis supports this hypothesis, suggesting that wing fluttering functions as an effective communicative gesture in this species, influencing male nesting behavior. However, because the frequency of the “after you” gesture varied greatly, especially in light of potential cognitive and other biases influencing the study, this bold claim should be taken with caution. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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18 pages, 4154 KiB

Open AccessArticle

The T-DBSCAN Algorithm for Stopover Site Identification of Migration Birds Based on Satellite Positioning Data

by Xinwu He, Xiqun Liu, Jiajia Liu, Youwen Li, Zhenggang Xu, Ping Mo and Tian Huang

Biology 2025, 14(3), 277; https://doi.org/10.3390/biology14030277 - 7 Mar 2025

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Abstract

With the acceleration of social development and urbanization, birds’ natural habitats have been greatly disturbed and threatened. Satellite tracking technology can collect much bird activity data, providing important data support for habitat protection research. However, satellite data are usually characterized by discontinuity, extensive [...] Read more.

With the acceleration of social development and urbanization, birds’ natural habitats have been greatly disturbed and threatened. Satellite tracking technology can collect much bird activity data, providing important data support for habitat protection research. However, satellite data are usually characterized by discontinuity, extensive periods, and inconsistent frequency, which challenges cluster analysis. Habitat research frequently employs clustering techniques, but conventional clustering algorithms struggle to adjust to these data features, particularly when it comes to time dimension changes and irregular data sampling. T-DBSCAN, an enhanced clustering algorithm, is suggested to accommodate this intricate data need. T-DBSCAN is improved based on the traditional DBSCAN algorithm, which combines a quadtree structure to optimize the efficiency of spatial partitioning and introduces a convex hull algorithmic strategy to perform the boundary identification and clustering processing, thus improving the efficiency and accuracy of the algorithm. T-DBSCAN is made to account efficiently for the uniformity of data sampling and changes in the time dimension. Tests demonstrate that the algorithm outperforms conventional habitat identification accuracy and processing efficiency techniques. It can also manage large amounts of discontinuous satellite tracking data, making it a dependable tool for studying bird habitats. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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17 pages, 3058 KiB

Open AccessArticle

Bird Richness and Abundance in Urban Areas: Simulation-Based Conservation Strategies for an Italian Town

by Alessandro Ferrarini, Luca Bagni and Marco Gustin

Biology 2025, 14(1), 37; https://doi.org/10.3390/biology14010037 - 6 Jan 2025

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Abstract

In this study, we (a) inventoried the breeding bird community of a town located in Northern Italy using quadrat sampling, (b) quantified bird richness and abundance, (c) measured sample completeness, (d) tested whether the bird community assembly was driven by environmental filtering (i.e., [...] Read more.

In this study, we (a) inventoried the breeding bird community of a town located in Northern Italy using quadrat sampling, (b) quantified bird richness and abundance, (c) measured sample completeness, (d) tested whether the bird community assembly was driven by environmental filtering (i.e., local properties of every single quadrat), e) explained bird richness and abundance in light of the land cover types present in each quadrat, (f) disentangled the marginal effects of every land cover type, and (g) simulated the effects on birds of different planning decisions. We recorded 36 breeding bird species, of which 17 were resident, 10 were mid-range migrants, and 9 were trans-Saharan migrators. The sampling completeness estimated ranged from 82.73% to 99.66% depending on the estimator procedure. Environmental filtering affected significantly (p < 0.10) the bird community assembly. Generalized Additive Models (GAMs) explained both bird richness (R² = 91.7%) and abundance (R² = 87.4%) satisfactorily in light of the land cover types. Simulations based on GAMs showed that local planners can largely influence bird richness in the study area, with both positive (urban greening) and negative (urban densification and sprawl) strategies. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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24 pages, 12619 KiB

Open AccessArticle

Quantifying the Ecological Performance of Migratory Bird Conservation: Evidence from Poyang Lake Wetlands in China

by Zhenjiang Song, Shichao Gao, Mingni Leng, Bo Zhou and Baoshu Wu

Biology 2024, 13(10), 786; https://doi.org/10.3390/biology13100786 - 30 Sep 2024

Cited by 1 | Viewed by 1689

Abstract

Protected areas are essential for the conservation of biodiversity. However, the rapid expansion of urbanization and the intensification of human activities have significantly disrupted environmental integrity, leading to a continuous deterioration in both the quantity and quality of large ecological patches. This has [...] Read more.

Protected areas are essential for the conservation of biodiversity. However, the rapid expansion of urbanization and the intensification of human activities have significantly disrupted environmental integrity, leading to a continuous deterioration in both the quantity and quality of large ecological patches. This has further diminished the connectivity among ecological patches, leading to significant consequences for regional biodiversity conservation. Taking Poyang Lake as a case study, which serves as a crucial wintering habitat for migratory birds along the East Asia–Australasia flyway, this research employs ArcMap technology. It considers various factors including land use type, slope, and elevation to evaluate habitat quality and degradation through the application of the InVEST model. Additionally, the study utilizes the minimum cumulative resistance (MCR) model alongside circuit theory to delineate ecological corridors within the area and to establish a comprehensive ecological network system. The research results in this paper are as follows. (i) During the period from 2000 to 2020, there was an overall decline in habitat quality within the study area, indicating a clear trend of habitat degradation. However, it is worth noting that there was an increase in habitat quality in certain local areas within the protected area. (ii) The ecological resistance values in the core area of the migratory bird reserve in Poyang Lake are generally low. However, the ecological resistance values of the habitats have shown a consistent increase from 2000 to 2020. Additionally, there has been a significant decrease in the density of ecological corridors during this time period. (iii) Over the period from 2000 to 2020, both the number and connectivity of ecological corridors decreased and their integrity and functionality degraded. Consequently, this weakened role of the ecological network has had implications for maintaining regional biodiversity and ecosystem service functions. The findings indicate two conclusions. (i) Ecological connectivity is essential for the conservation of migratory bird habitats. Strengthening control measures aimed at expanding ecological corridors can effectively safeguard flagship and umbrella species, thereby promoting biodiversity conservation. (ii) The establishment of ecological corridors can help reconcile conflicts between conservation efforts and development objectives. This reconciliation carries significant theoretical implications for fostering a harmonious coexistence between humans and birds in Poyang Lake’s migratory bird sanctuary. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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18 pages, 772 KiB

Open AccessEditor’s ChoiceReview

Trait Variation and Spatiotemporal Dynamics across Avian Secondary Contact Zones

by Shangyu Wang, Lei Wu, Qianghui Zhu, Jiahao Wu, Shiyu Tang, Yifang Zhao, Yalin Cheng, Dezhi Zhang, Gexia Qiao, Runzhi Zhang and Fumin Lei

Biology 2024, 13(8), 643; https://doi.org/10.3390/biology13080643 - 22 Aug 2024

Viewed by 1662

Abstract

A secondary contact zone (SCZ) is an area where incipient species or divergent populations may meet, mate, and hybridize. Due to the diverse patterns of interspecific hybridization, SCZs function as field labs for illuminating the on-going evolutionary processes of speciation and the establishment [...] Read more.

A secondary contact zone (SCZ) is an area where incipient species or divergent populations may meet, mate, and hybridize. Due to the diverse patterns of interspecific hybridization, SCZs function as field labs for illuminating the on-going evolutionary processes of speciation and the establishment of reproductive isolation. Interspecific hybridization is widely present in avian populations, making them an ideal system for SCZ studies. This review exhaustively summarizes the variations in unique traits within avian SCZs (vocalization, plumage, beak, and migratory traits) and the various movement patterns of SCZs observed in previous publications. It also highlights several potential future research directions in the genomic era, such as the relationship between phenotypic and genomic differentiation in SCZs, the genomic basis of trait differentiation, SCZs shared by multiple species, and accurate predictive models for forecasting future movements under climate change and human disturbances. This review aims to provide a more comprehensive understanding of speciation processes and offers a theoretical foundation for species conservation. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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Other

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19 pages, 49846 KiB

Open AccessCase Report

Population Status of Sympatrically Breeding Skuas (Catharacta spp.) at Admiralty Bay, King George Island, Antarctica: A Case Report for 2020–2024

by Katarzyna Komarowska, Katarzyna Fudala, Michał Dziembowski, Alexander Hagge and Robert Józef Bialik

Biology 2025, 14(3), 305; https://doi.org/10.3390/biology14030305 - 17 Mar 2025

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Abstract

The present study sets out to examine the status of sympatric populations of south polar (Catharacta maccormicki) (SPSs) and brown skuas (Catharacta antarctica) (BSs) at two sites on King George Island, Antarctica. The study sites were designated as Important [...] Read more.

The present study sets out to examine the status of sympatric populations of south polar (Catharacta maccormicki) (SPSs) and brown skuas (Catharacta antarctica) (BSs) at two sites on King George Island, Antarctica. The study sites were designated as Important Bird and Biodiversity Areas (IBAs) and were monitored for three (for Point Hennequin (PH)) and four (for West Admiralty Bay (WAB)) consecutive breeding seasons, concluding with the 2023/24 season. The most recently reported data from these areas are from the 2004/05 season, and the data presented herein allow both areas to be assessed in the context of their IBA and Antarctic Specially Protected Area values. The mean number of total pairs for the investigated seasons for WAB was 67 ± 7, while for PH, it was 157 ± 18. The number of pairs of SPSs at PH and WAB justifies the positive evaluation of the areas as IBAs based on global designation criterion A4 proposed jointly by BirdLife International and the Scientific Committee on Antarctic Research (SCAR). PH is of particular interest, as it has been determined that at least 2.3% of the global population of SPSs, estimated by BirdLife International to be between 6000 and 15,000 adult individuals, breeds at this site. The expansion of both IBA boundaries is also recommended based on this study. Full article

(This article belongs to the Special Issue Bird Biology and Conservation)

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