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Assessing habitat quality is critical for migrating birds, with implications for fuel loading, predation risk and timing of departure. To efficiently distribute within stopover sites, migrants rely on various cues that facilitate habitat quality assessment. In this study, we conducted a playback experiment at a mid‐route stopover site to test the effects of vocal cues, specifically bird songs, on habitat redistribution during spring migration. To estimate the effect of bird songs on bird abundance we mist‐netted and ringed birds for 60 days on alternating playback treatment (playing songs of three sylviid warbler species) and no playback (control) days. A nearby site was used to control for fluctuations caused by migration waves. Overall, total bird abundance was significantly increased by the playback treatment. This increase resulted from the attraction of conspecifics (species whose songs were played) rather than of other species – sylviids or others. Correspondingly, species richness was seemingly unaffected. To investigate the relationship between internal‐state factors and the attraction to playback in the most abundantly attracted species, Eurasian Blackcap Sylvia atricapilla, we tested associations with age, sex and body condition index but found no significant effects, possibly because of the limited sample size. Our findings challenge established ideas regarding heterospecific attraction and contradict previous studies. Attraction to bird song is discussed in the context of geographical location, timing and internal drivers. Vocal cues, specifically bird songs, may affect micro‐habitat selection by migrating songbirds during stopovers. Consequently, we call for consideration of the influence of the acoustic environment on birds during migratory stopover in future studies, habitat management and conservation efforts. [ABSTRACT FROM AUTHOR]

Migratory birds excel in phenotypic flexibility, adapting physiologically as their life histories and environments require. Discerning the metabolic processes underlying migrants' physiology, an emergent property of multiple continuous and dynamic organism–environment interactions, is therefore challenging, particularly under natural conditions. Accordingly, analyses of snapshot‐sampled serum‐circulating metabolites, versatile and readily applicable for migrating birds, have increasingly become the method of choice for such physiologic inference. However, the atemporal nature of single sampling might obscure the links between observed metabolite concentrations and the processes producing them, necessitating an analytical decoupling of focal processes from their broader biochemical background.In the present study, we examined how variation in combined fat and muscle fuel stores, traits pivotal in migratory context, relates to the serum‐circulating metabolomes of spring‐migrating Eurasian blackcaps stopping‐over. Our analyses accounted for potential spatiotemporal influences in the form of time past night's fasting and random local conditions across three sites within the Negev Desert. We shifted the focus from compound‐level analysis of preselected metabolites towards the level of inclusive metabolome, quantifying serum‐circulating lipophilic and polar molecules via UHPLC–MS/MS untargeted metabolomic technique.Our results indicated a general relationship between fuel stores and the metabolome, comprising 16 326 lipophilic and 6923 polar compounds, among which 918 and 44 were annotated, respectively. By applying generalized latent‐variable linear modeling (GLLVM) upon concentrations of annotated metabolites, we identified several candidate biomarkers, some novel in migratory context, notably the fuel‐associated increase in serum ceramides likely derived from circulating very low‐density lipoproteins (VLDLs). Relying on estimated metabolite links with fuel and foraging time and on modeled residual covariations among metabolites, we demonstrate fuel–metabolite associations generally consistent with higher fat‐ and lower protein mobilization in birds having greater stores and with decreased fuel utilization as ingested nutrients accumulate over time, thus introducing a novel approach for the physiological study of migrating birds. [ABSTRACT FROM AUTHOR]

Background: While the dynamics of disease emergence is driven by host–parasite interactions, the structure and dynamics of these interactions are still poorly understood. Here we study the phylogenetic and morphological clustering of haemosporidian parasite lineages in a local avian host community. Subsequently, we examine geographical patterns of parasite assemblages in selected avian hosts breeding in Europe. Methods: We conduct phylogenetic and haplotype network analyses of Haemoproteus (Parahaemoproteus) lineages based on a short and an extended cytochrome b barcode region. Ordination analyses are used to examine changes in parasite assemblages with respect to climate type and geography. Results: We reveal relatively low phylogenetic clustering of haemoproteid lineages in a local avian host community and identify a potentially new Haemoproteus morphospecies. Further, we find that climate is effectively capturing geographical changes in parasite assemblages in selected widespread avian hosts. Moreover, parasite assemblages are found to vary distinctly across the host's breeding range, even within a single avian host. Conclusions: This study suggests that a few keystone hosts can be important for the local phylogenetic and morphological clustering of haemoproteid parasites. Host spatio-temporal dynamics, both for partially and long-distance migratory birds, appear to explain geographical variation in haemoproteid parasite assemblages. This study also gives support to the idea that climate variation in terms of rainfall seasonality can be linked to the propensity for host switching in haemosporidians. [ABSTRACT FROM AUTHOR]

Background: While the dynamics of disease emergence is driven by host–parasite interactions, the structure and dynamics of these interactions are still poorly understood. Here we study the phylogenetic and morphological clustering of haemosporidian parasite lineages in a local avian host community. Subsequently, we examine geographical patterns of parasite assemblages in selected avian hosts breeding in Europe. Methods: We conduct phylogenetic and haplotype network analyses of Haemoproteus (Parahaemoproteus) lineages based on a short and an extended cytochrome b barcode region. Ordination analyses are used to examine changes in parasite assemblages with respect to climate type and geography. Results: We reveal relatively low phylogenetic clustering of haemoproteid lineages in a local avian host community and identify a potentially new Haemoproteus morphospecies. Further, we find that climate is effectively capturing geographical changes in parasite assemblages in selected widespread avian hosts. Moreover, parasite assemblages are found to vary distinctly across the host’s breeding range, even within a single avian host. Conclusions: This study suggests that a few keystone hosts can be important for the local phylogenetic and morphological clustering of haemoproteid parasites. Host spatio-temporal dynamics, both for partially and long-distance migratory birds, appear to explain geographical variation in haemoproteid parasite assemblages. This study also gives support to the idea that climate variation in terms of rainfall seasonality can be linked to the propensity for host switching in haemosporidians.