摘要: Inclusive fitness theory posits that altruistic behaviors, which are directed more likely towards relatives, should be favored by natural selection. However, the prevalence of alternative parenting behaviors in offspring selection, including rejecting their own offspring and accepting the offspring of others, remains poorly understood within the context of parental care evolution. In order to investigate the factors that prompt the occurrence of alternative parenting behaviors, we designed a series of experiments in the Azure-winged Magpie(Cyanopica cyanus). By manipulating the nest spatial position or offspring age/number and parent-offspring familiarity, we addressed how parents provided parental care for the manipulated offspring. In the nest resettlement experiment, the probability of parents rejecting their own offspring significantly increased with nest-moving distances while decreased with offspring ages. In the cross-fostering experiments, the probability of parents provisioning unrelated young significantly decreased with the age difference between cross-fostered chicks. In the nest duplication experiments, where parents were given a choice between familiar offspring and unfamiliar unrelated chicks or between unfamiliar offspring and familiar unrelated chicks, the probability of both alternative parenting behaviors was significantly influenced by the time when parental association with their offspring was deprived. We conclude that as offspring phenotypic traits become individualized and fixed at a special developmental stage, parents gradually acquire the capacity for offspring recognition by associating with them. Any factors that disrupt parent–offspring association or introduce unrelated young into the nest prior to this critical timeline can result in the occurrence of alternative parenting behaviors.

摘要: Urban environments have challenging characteristics for bird acoustic communication. High levels of anthropogenic noise, as well as vegetation structure(e.g., in urban parks), can potentially affect the song frequency characteristics of several bird species. An additional factor such as the abundance of conspecific and heterospecific vocalizing birds may play an important role in determining the structure of bird songs. In this study, we analyzed whether noise levels, vegetation percentage, and abundance of conspecifics and heterospecifics influence the song characteristics of three syntopic songbird species: House Finch(Haemorhous mexicanus), Rufouscollared Sparrow(Zonotrichia capensis), and House Sparrow(Passer domesticus) living in urban sites. We recorded songs of these species and measured the peak frequency and entropy of their songs at 14 sites in the city of San Cristobal de Las Casas, Chiapas, Mexico. We found that the song peak frequency of House Finch and House Sparrow's songs was negatively related to the vegetation. The peak frequency of neither of the three species correlated with the average noise level. However, the abundances of conspecific and heterospecific were related to the peak frequency of the three species' songs. The entropy of the House Finch and House Sparrow songs was positively and negatively related, respectively, to noise levels. House Sparrow song entropy was negatively related to the percentage of vegetation. Song entropy of House Finches was negatively associated to conspecific and House Sparrow abundance. Song entropy of Rufous-collared Sparrows was positively related to conspecific abundance. In conclusion, the song peak frequency and song entropy of the three songbird species were differentially related to urban noise, vegetation, and conspecific and heterospecific abundance, suggesting these factors influence bird song characteristics.

摘要: Birdsong is an important secondary sexual trait which may vary between but also within species. Intraspecific variation is generally studied either on the geographical or on the temporal scale; most of the studies exploring the variation of song over time, however, focused on species with rather simple songs. In this study, we explored the temporal changes in song of a complex songster, the Thrush Nightingale(Luscinia luscinia), recorded after 33 years(in 1986 and 2019) at the same locality in south-eastern Finland. Our analysis revealed a complete turnover of song types over the study period, with no song type shared between the two recording years. In contrast, 40% of the originally recorded syllable types were still found in the repertoires of recently recorded males. Their song type repertoires were significantly smaller but the songs themselves were on average longer compared to the 1986 recordings. Repertoires of both syllables and song types were more shared between males recorded in 1986 than between those from 2019. We discuss the processes that may have contributed to these temporal changes in song and call for more detailed studies of song evolution in wild populations.

摘要: Bird vocalizations are pivotal for ecological monitoring, providing insights into biodiversity and ecosystem health. Traditional recognition methods often neglect phase information, resulting in incomplete feature representation. In this paper, we introduce a novel approach to bird vocalization recognition(BVR) that integrates both amplitude and phase information, leading to enhanced species identification. We propose MHARes Net, a deep learning(DL) model that employs residual blocks and a multi-head attention mechanism to capture salient features from logarithmic power(POW), Instantaneous Frequency(IF), and Group Delay(GD) extracted from bird vocalizations. Experiments on three bird vocalization datasets demonstrate our method's superior performance, achieving accuracy rates of 94%, 98.9%, and 87.1% respectively. These results indicate that our approach provides a more effective representation of bird vocalizations, outperforming existing methods. This integration of phase information in BVR is innovative and significantly advances the field of automatic bird monitoring technology, offering valuable tools for ecological research and conservation efforts.