Natural sounds, and bird song in particular, play a key role in building and maintaining our connection with nature, but widespread declines in bird populations mean that the acoustic properties of natural soundscapes may be changing. Using data-driven reconstructions of soundscapes in lieu of historical recordings, here we quantify changes in soundscape characteristics at more than 200,000 sites across North America and Europe. We integrate citizen science bird monitoring data with recordings of individual species to reveal a pervasive loss of acoustic diversity and intensity of soundscapes across both continents over the past 25 years, driven by changes in species richness and abundance. These results suggest that one of the fundamental pathways through which humans engage with nature is in chronic decline, with potentially widespread implications for human health and well-being.

• MeSH
• akustika * MeSH
• biodiverzita MeSH
• lidé MeSH
• populační dynamika MeSH
• ptáci klasifikace   fyziologie   MeSH
• roční období MeSH
• vokalizace zvířat klasifikace   fyziologie   MeSH
• zachování přírodních zdrojů MeSH
• zvířata MeSH
• zvuk MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH
• Severní Amerika MeSH

Recent studies indicate that yawning evolved as a brain cooling mechanism. Given that larger brains have greater thermolytic needs and brain temperature is determined in part by heat production from neuronal activity, it was hypothesized that animals with larger brains and more neurons would yawn longer to produce comparable cooling effects. To test this, we performed the largest study on yawning ever conducted, analyzing 1291 yawns from 101 species (55 mammals; 46 birds). Phylogenetically controlled analyses revealed robust positive correlations between yawn duration and (1) brain mass, (2) total neuron number, and (3) cortical/pallial neuron number in both mammals and birds, which cannot be attributed solely to allometric scaling rules. These relationships were similar across clades, though mammals exhibited considerably longer yawns than birds of comparable brain and body mass. These findings provide further evidence suggesting that yawning is a thermoregulatory adaptation that has been conserved across amniote evolution.

• MeSH
• mozek anatomie a histologie   fyziologie   MeSH
• neurony cytologie   fyziologie   MeSH
• ptáci anatomie a histologie   fyziologie   MeSH
• savci anatomie a histologie   fyziologie   MeSH
• velikost orgánu MeSH
• zívání * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Ground-nesting birds face many challenges to reproduce successfully, with nest predation being the main cause of reproductive failure. Visual predators such as corvids and egg-eating raptors, are among the most common causes of nest failure; thus, parental strategies that reduce the risk of visual nest predation should be favored by selection. To date, most research has focused on egg crypsis without considering adult crypsis, although in natural circumstances the eggs are covered by an incubating parent most of the time. Here we use a ground-nesting shorebird, the Kentish plover (Charadrius alexandrinus) as model species to experimentally test whether decoy parents influence nest predation. Using artificial nests with a male decoy, a female decoy or no decoy, we found that the presence of a decoy increased nest predation (N = 107 nests, p < 0.001). However, no difference was found in predation rates between nests with a male versus female decoy (p > 0.05). Additionally, we found that nests in densely vegetated habitats experienced higher survival compared to nests placed in sparsely vegetated habitats. Nest camera images, predator tracks and marks left on eggs identified the brown-necked raven (Corvus ruficollis) as the main visual nest predator. Our study suggests that the presence of incubating parents may enhance nest detectability to visual predators. However, parents may reduce the predation risk by placing a nest in sites where they are covered by vegetation. Our findings highlight the importance of nest site selection not only regarding egg crypsis but also considering incubating adult camouflage.

• MeSH
• ekosystém MeSH
• hnízdění fyziologie   MeSH
• hustota populace MeSH
• ovum fyziologie   MeSH
• predátorské chování fyziologie   MeSH
• pryskyřičné cementy chemie   MeSH
• ptáci fyziologie   MeSH
• rozmnožování fyziologie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The red-crowned crane (Grus japonensis) is a vulnerable bird species. Mycotoxins are toxic substances produced by filamentous fungi and are considered as naturally unavoidable contaminants in animal feed. Our recent survey indicated that feeds designed for captive red-crowned cranes were contaminated with mycotoxins. This study was conducted to investigate the protective effects of the mycotoxin binder montmorillonite on the reproductive behavior, sex hormone levels, and egg quality of red-crowned cranes. Twelve pairs of G. japonensis were divided into four groups, and each group was fed one of the following: a selected diet (with extra low levels of mycotoxins), a regular diet, a selected diet with 0.5% montmorillonite added, or a regular diet with 0.5% montmorillonite added. Consumption of the regular diet decreased courtship and mating behaviors, testosterone concentration, egg weight, and shell thickness. However, feed supplementation with montmorillonite increased the courtship, mating behaviors and testosterone concentration during the pre-breeding period, as well as egg weight and shell thickness. These findings suggest that the addition of dietary montmorillonite is effective for controlling mycotoxins in the feed, resulting in improvements in reproductive behaviors, testosterone concentrations, and some egg quality parameters of the red-crowned crane.

• MeSH
• bentonit chemie   MeSH
• dieta MeSH
• krmivo pro zvířata analýza   normy   MeSH
• mykotoxiny analýza   toxicita   MeSH
• ovum chemie   MeSH
• pohlavní steroidní hormony krev   MeSH
• ptáci fyziologie   MeSH
• rozmnožování účinky léků   MeSH
• sexuální chování zvířat účinky léků   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Several hypotheses have been proposed to explain the mechanisms responsible for maintenance of host-specific gentes in the common cuckoo (Cuculus canorus). Some of them expect that when adult cuckoos return to lay their eggs to their natal site (natal philopatry hypothesis) or habitat in which they were reared (habitat-imprinting hypothesis), there is a higher probability of finding nests of the host species by which they were reared. Since published evidence is ambiguous, we here evaluate the natal philopatry and habitat-imprinting hypotheses using information on habitat homogeneity and cross-continental long-term ringing data. We found no evidence for the natal philopatry hypothesis-instead of returning to their natal site, juvenile cuckoos exhibited longer dispersal movements than adults, and the difference was even larger in comparison with a wide array of cuckoo host species. On the contrary, we found support for the habitat-imprinting hypothesis-juvenile cuckoos followed similar levels of natal habitat homogeneity at 5- and 25-km scale when returning to breed in the next years. Our results suggest that preference for the particular habitat structures may help cuckoos to find appropriate hosts.

• MeSH
• ekosystém * MeSH
• hostitelská specificita * MeSH
• imprinting (psychologie) MeSH
• paraziti fyziologie   MeSH
• ptáci fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Avian brood parasites lay their eggs in other birds' nests, and hosts can mitigate the fitness cost of raising unrelated offspring by rejecting parasitic eggs. A visually-based cognitive mechanism often thought to be used by hosts to discriminate the foreign egg is to compare it against the hosts' own eggshell by size, shape, maculation, and/or ground coloration (i.e., absolute chromatic contrast). However, hosts may instead discriminate eggs based on their colors along a scale of natural avian eggshell coloration (i.e., directional chromatic contrast). In support of this latter visual process, recent research has found that directional chromatic contrasts can explain some host species' rejection behavior better than absolute chromatic or achromatic contrasts. Here, for the first time, we conducted an experiment in a cavity-nesting host species to test the predictions of these different visual mechanisms. We experimentally parasitized nests of the Common Redstart Phoenicurus phoenicurus, a regular host of a mimetic-egg laying Common Cuckoo Cuculus canorus host-race, using painted, immaculate 3D-printed model eggs in two geographically distant areas (Finland and Czech Republic). We found that directional chromatic contrasts better explained rejection behaviors in both parasitized (Finland) and non-parasitized (Czech Republic) host populations, as hosts rejected eggs that were noticeably browner, but not eggs that were noticeably bluer, than redstart eggs. These results support the paradigm of a single rejection threshold predicted by the directional chromatic contrast model and contribute to a growing generality of these patterns across diverse avian host-brood parasite systems.

• MeSH
• barva MeSH
• biologické modely * MeSH
• hnízdění fyziologie   MeSH
• interakce hostitele a parazita MeSH
• ovum fyziologie   MeSH
• Passeriformes fyziologie   MeSH
• podněty MeSH
• ptáci fyziologie   MeSH
• rozpoznávání (psychologie) MeSH
• vaječná skořápka * MeSH
• zraková percepce fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mountain areas often hold special species communities, and they are high on the list of conservation concern. Global warming and changes in human land use, such as grazing pressure and afforestation, have been suggested to be major threats for biodiversity in the mountain areas, affecting species abundance and causing distribution shifts towards mountaintops. Population shifts towards poles and mountaintops have been documented in several areas, indicating that climate change is one of the key drivers of species' distribution changes. Despite the high conservation concern, relatively little is known about the population trends of species in mountain areas due to low accessibility and difficult working conditions. Thanks to the recent improvement of bird monitoring schemes around Europe, we can here report a first account of population trends of 44 bird species from four major European mountain regions: Fennoscandia, UK upland, south-western (Iberia) and south-central mountains (Alps), covering 12 countries. Overall, the mountain bird species declined significantly (-7%) during 2002-2014, which is similar to the declining rate in common birds in Europe during the same period. Mountain specialists showed a significant -10% decline in population numbers. The slope for mountain generalists was also negative, but not significantly so. The slopes of specialists and generalists did not differ from each other. Fennoscandian and Iberian populations were on average declining, while in United Kingdom and Alps, trends were nonsignificant. Temperature change or migratory behaviour was not significantly associated with regional population trends of species. Alpine habitats are highly vulnerable to climate change, and this is certainly one of the main drivers of mountain bird population trends. However, observed declines can also be partly linked with local land use practices. More efforts should be undertaken to identify the causes of decline and to increase conservation efforts for these populations.

• MeSH
• biodiverzita * MeSH
• ekosystém * MeSH
• klimatické změny * MeSH
• populační dynamika MeSH
• ptáci fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species.

• MeSH
• aklimatizace fyziologie   MeSH
• časové faktory MeSH
• fenotyp * MeSH
• klimatické změny * MeSH
• ptáci fyziologie   MeSH
• selekce (genetika) fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• metaanalýza MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• systematický přehled MeSH

Animal microbiomes play an important role in dietary adaptation, yet the extent to which microbiome changes exhibit parallel evolution is unclear. Of particular interest is an adaptation to extreme diets, such as blood, which poses special challenges in its content of proteins and lack of essential nutrients. In this study, we assessed taxonomic signatures (by 16S rRNA amplicon profiling) and potential functional signatures (inferred by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt)) of haematophagy in birds and bats. Our goal was to test three alternative hypotheses: no convergence of microbiomes, convergence in taxonomy and convergence in function. We find a statistically significant effect of haematophagy in terms of microbial taxonomic convergence across the blood-feeding bats and birds, although this effect is small compared to the differences found between haematophagous and non-haematophagous species within the two host clades. We also find some evidence of convergence at the predicted functional level, although it is possible that the lack of metagenomic data and the poor representation of microbial lineages adapted to haematophagy in genome databases limit the power of this approach. The results provide a paradigm for exploring convergent microbiome evolution replicated with independent contrasts in different host lineages. This article is part of the theme issue 'Convergent evolution in the genomics era: new insights and directions'.

• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• biologická evoluce MeSH
• Chiroptera genetika   mikrobiologie   fyziologie   MeSH
• DNA bakterií genetika   MeSH
• fylogeneze MeSH
• ptáci genetika   mikrobiologie   fyziologie   MeSH
• RNA ribozomální 16S genetika   MeSH
• stravovací zvyklosti MeSH
• střevní mikroflóra * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

In many taxa, the most common form of sex-biased migration timing is protandry-the earlier arrival of males at breeding areas. Here we test this concept across the annual cycle of long-distance migratory birds. Using more than 350 migration tracks of small-bodied trans-Saharan migrants, we quantify differences in male and female migration schedules and test for proximate determinants of sex-specific timing. In autumn, males started migration about 2 days earlier, but this difference did not carry over to arrival at the non-breeding sites. In spring, males on average departed from the African non-breeding sites about 3 days earlier and reached breeding sites ca 4 days ahead of females. A cross-species comparison revealed large variation in the level of protandry and protogyny across the annual cycle. While we found tight links between individual timing of departure and arrival within each migration season, only for males the timing of spring migration was linked to the timing of previous autumn migration. In conclusion, our results demonstrate that protandry is not exclusively a reproductive strategy but rather occurs year-round and the two main proximate determinants for the magnitude of sex-biased arrival times in autumn and spring are sex-specific differences in departure timing and migration duration.

• MeSH
• migrace zvířat * MeSH
• ptáci fyziologie   MeSH
• roční období MeSH
• rozmnožování MeSH
• sexuální faktory MeSH
• zpěvní ptáci fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH
• severní Afrika MeSH