Wild

Reproductive seasonality in birds represents a key ecological adaptation that ensures synchronization between breeding activity and optimal environmental conditions for offspring survival and development. Photoperiod is the primary cue regulating the hypothalamic–pituitary–gonadal (HPG) axis, through brain photoreceptors and pineal melatonin secretion. Increasing day length induces thyroid hormone activation by hypothalamic type 2 deiodinase (DIO2), stimulates gonadotropin-releasing hormone (GnRH) secretion, and promotes gonadal growth, whereas prolonged exposure to long days triggers photorefractoriness, which has been linked to increased hypothalamic type 3 deiodinase (DIO3) expression in several studies, although the causal role of this enzyme remains under investigation. Secondary environmental modulators, such as temperature, food supply, precipitation, and social interactions, also play crucial roles in fine-tuning reproductive timing. Moreover, anthropogenic factors like artificial light at night can disrupt circadian and seasonal regulation, causing mismatches between breeding and food availability. Evidence from diverse species, including passerines, galliforms, waterfowl, and raptors, demonstrates both conserved mechanisms and ecological plasticity, with tropical and urban species showing more opportunistic breeding strategies. These findings highlight the multifactorial and flexible nature of avian reproductive cycles, underlining their vulnerability to climate change and habitat anthropization. Considering this, this review aimed to understand the neuroendocrine and environmental control of seasonality and to offer an integrative perspective on how light, hormones, and environmental factors interact to shape seasonal reproduction in wild birds.

Human–wildlife conflicts can be broadly categorized from the perspective of human activities into conflicts (a) caused by the expansion of human activities into wildlife habitats, and (b) resulting from the re-expansion of wildlife habitats due to the decline of human activities. The first type of conflict has been managed through the systematic training of wildlife managers, field specialists, and well-organized institutional frameworks. In Japan, Asiatic black bears (Ursus thibetanus) and brown bears (Ursus arctos) have increasingly come into human contact because of habitat re-expansion. Short-term measures to protect human life and property include the implementation of the 2024 and 2025 revisions of the Wildlife Protection and Hunting Management Act, which designated bears as “managed wildlife” and “dangerous wildlife” and permitted emergency culling in residential areas. However, Japan’s approach remains limited in scope and depth, relies on ad hoc responses by local hunters, and lacks adequate public education and effective long-term sustainability planning. This study highlights the necessity of a multi-layered policy framework that integrates human–wildlife conflict management, particularly human–bear conflict, by comparing U.S. laws and policies and incorporating them into medium- and long-term strategies for community resilience and national land conservation. This approach may serve as a model for countries and regions facing similar demographic and ecological challenges.

As human activities such as urbanization encroach on natural areas, some wildlife species adapt to these changes and learn ways to utilize newly available resources. We monitored the use patterns of the Eurasian otter in three urban ponds in southern Spain (Málaga province). We compared weekly otter visits and relative spraint abundance between the urban ponds and two control ponds located in natural areas, testing for differences in use patterns between them using Generalized Linear Mixed Models and the Wald–Wolfowitz run test. We also estimated prey survival rates through Kaplan–Meier estimator curves. We also assessed problems of coexistence with human interests. Relative spraint abundance was not affected by pond type (urban or natural). However, the number of otter visits was lower for urban ponds, and the pattern was not random but concentrated over a short time until prey depletion, suggesting consistent use of the urban feeding patches. Available food resources in urban settings can become a viable option for otters, which appear to explore urban habitats when it suits them. However, in the monitored urban ponds, otters competed with human interests and generated a conservation problem that almost led to lethal measures.