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2.
Nat Commun ; 12(1): 4780, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362899

RESUMO

Globally, bird migration is occurring earlier in the year, consistent with climate-related changes in breeding resources. Although often attributed to phenotypic plasticity, there is no clear demonstration of long-term population advancement in avian migration through individual plasticity. Using direct observations of bar-tailed godwits (Limosa lapponica) departing New Zealand on a 16,000-km journey to Alaska, we show that migration advanced by six days during 2008-2020, and that within-individual advancement was sufficient to explain this population-level change. However, in individuals tracked for the entire migration (50 total tracks of 36 individuals), earlier departure did not lead to earlier arrival or breeding in Alaska, due to prolonged stopovers in Asia. Moreover, changes in breeding-site phenology varied across Alaska, but were not reflected in within-population differences in advancement of migratory departure. We demonstrate that plastic responses can drive population-level changes in timing of long-distance migration, but also that behavioral and environmental constraints en route may yet limit adaptive responses to global change.


Assuntos
Adaptação Fisiológica , Migração Animal/fisiologia , Aves/fisiologia , Charadriiformes/fisiologia , Alaska , Animais , Ásia , Cruzamento , Mudança Climática , Feminino , Masculino , Nova Zelândia , Estações do Ano
3.
Biomolecules ; 11(8)2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34439736

RESUMO

We recently reported that artificial light at night (ALAN), at ecologically relevant intensities (1.5, 5 lux), increases cell proliferation in the ventricular zone and recruitment of new neurons in several forebrain regions of female zebra finches (Taeniopygia guttata), along with a decrease of total neuronal densities in some of these regions (indicating possible neuronal death). In the present study, we exposed male zebra finches to the same ALAN intensities, treated them with 5'-bromo-2'-deoxyuridine, quantified cell proliferation and neuronal recruitment in several forebrain regions, and compared them to controls that were kept under dark nights. ALAN increased cell proliferation in the ventricular zone, similar to our previous findings in females. We also found, for the first time, that ALAN increased new neuronal recruitment in HVC and Area X, which are part of the song system in the brain and are male-specific. In other brain regions, such as the medial striatum, nidopallium caudale, and hippocampus, we recorded an increased neuronal recruitment only in the medial striatum (unlike our previous findings in females), and relative to the controls this increase was less prominent than in females. Moreover, the effect of ALAN duration on total neuronal densities in the studied regions varied between the sexes, supporting the suggestion that males are more resilient to ALAN than females. Suppression of nocturnal melatonin levels after ALAN exhibited a light intensity-dependent decrease in males in contrast to females, another indication that males might be less affected by ALAN. Taken together, our study emphasizes the importance of studying both sexes when considering ALAN effects on brain plasticity.


Assuntos
Aves/fisiologia , Encéfalo , Luz/efeitos adversos , Melatonina/metabolismo , Plasticidade Neuronal , Neurônios/citologia , Animais , Feminino , Masculino
4.
Nat Commun ; 12(1): 4572, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34315894

RESUMO

Individual variation is increasingly recognized as a central component of ecological processes, but its role in structuring environmental niche associations remains largely unknown. Species' responses to environmental conditions are ultimately determined by the niches of single individuals, yet environmental associations are typically captured only at the level of species. Here, we develop scenarios for how individual variation may combine to define the compound environmental niche of populations, use extensive movement data to document individual environmental niche variation, test associated hypotheses of niche configuration, and examine the consistency of individual niches over time. For 45 individual white storks (Ciconia ciconia; 116 individual-year combinations), we uncover high variability in individual environmental associations, consistency of individual niches over time, and moderate to strong niche specialization. Within populations, environmental niches follow a nested pattern, with individuals arranged along a specialist-to-generalist gradient. These results reject common assumptions of individual niche equivalency among conspecifics, as well as the separation of individual niches into disparate parts of environmental space. These findings underscore the need for a more thorough consideration of individualistic environmental responses in global change research.


Assuntos
Migração Animal/fisiologia , Aves/fisiologia , Ecossistema , Animais , Cruzamento , Comportamento de Retorno ao Território Vital , Estações do Ano
6.
Science ; 373(6551): 226-231, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34244416

RESUMO

Early events in the evolutionary history of a clade can shape the sensory systems of descendant lineages. Although the avian ancestor may not have had a sweet receptor, the widespread incidence of nectar-feeding birds suggests multiple acquisitions of sugar detection. In this study, we identify a single early sensory shift of the umami receptor (the T1R1-T1R3 heterodimer) that conferred sweet-sensing abilities in songbirds, a large evolutionary radiation containing nearly half of all living birds. We demonstrate sugar responses across species with diverse diets, uncover critical sites underlying carbohydrate detection, and identify the molecular basis of sensory convergence between songbirds and nectar-specialist hummingbirds. This early shift shaped the sensory biology of an entire radiation, emphasizing the role of contingency and providing an example of the genetic basis of convergence in avian evolution.


Assuntos
Evolução Biológica , Néctar de Plantas , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/metabolismo , Aves Canoras/fisiologia , Percepção Gustatória , Aminoácidos , Animais , Proteínas Aviárias/química , Proteínas Aviárias/metabolismo , Aves/fisiologia , Carboidratos , Dieta , Comportamento Alimentar , Multimerização Proteica , Sacarose
7.
Genes (Basel) ; 12(5)2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34069986

RESUMO

The transition of amniotes to a fully terrestrial lifestyle involved the adaptation of major molecular innovations to the epidermis, often in the form of epidermal appendages such as hair, scales and feathers. Feathers are diverse epidermal structures of birds, and their evolution has played a key role in the expansion of avian species to a wide range of lifestyles and habitats. As with other epidermal appendages, feather development is a complex process which involves many different genetic and protein elements. In mammals, many of the genetic elements involved in epidermal development are located at a specific genetic locus known as the epidermal differentiation complex (EDC). Studies have identified a homologous EDC locus in birds, which contains several genes expressed throughout epidermal and feather development. A family of avian EDC genes rich in aromatic amino acids that also contain MTF amino acid motifs (EDAAs/EDMTFs), that includes the previously reported histidine-rich or fast-protein (HRP/fp), an important marker in feather development, has expanded significantly in birds. Here, we characterize the EDAA gene family in birds and investigate the evolutionary history and possible functions of EDAA genes using phylogenetic and sequence analyses. We provide evidence that the EDAA gene family originated in an early archosaur ancestor, and has since expanded in birds, crocodiles and turtles, respectively. Furthermore, this study shows that the respective amino acid compositions of avian EDAAs are characteristic of structural functions associated with EDC genes and feather development. Finally, these results support the hypothesis that the genes of the EDC have evolved through tandem duplication and diversification, which has contributed to the evolution of the intricate avian epidermis and epidermal appendages.


Assuntos
Aves/genética , Aves/fisiologia , Epiderme/fisiologia , Família Multigênica/genética , Motivos de Aminoácidos/genética , Aminoácidos/genética , Animais , Biomarcadores/metabolismo , Evolução Molecular , Plumas/fisiologia , Mamíferos/genética , Mamíferos/fisiologia , Proteínas/genética , Sequências de Repetição em Tandem/genética
8.
Nature ; 595(7865): 75-79, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34163068

RESUMO

Climate change is forcing the redistribution of life on Earth at an unprecedented velocity1,2. Migratory birds are thought to help plants to track climate change through long-distance seed dispersal3,4. However, seeds may be consistently dispersed towards cooler or warmer latitudes depending on whether the fruiting period of a plant species coincides with northward or southward migrations. Here we assess the potential of plant communities to keep pace with climate change through long-distance seed dispersal by migratory birds. To do so, we combine phenological and migration information with data on 949 seed-dispersal interactions between 46 bird and 81 plant species from 13 woodland communities across Europe. Most of the plant species (86%) in these communities are dispersed by birds migrating south, whereas only 35% are dispersed by birds migrating north; the latter subset is phylogenetically clustered in lineages that have fruiting periods that overlap with the spring migration. Moreover, the majority of this critical dispersal service northwards is provided by only a few Palaearctic migrant species. The potential of migratory birds to assist a small, non-random sample of plants to track climate change latitudinally is expected to strongly influence the formation of novel plant communities, and thus affect their ecosystem functions and community assembly at higher trophic levels.


Assuntos
Aclimatação , Migração Animal , Aves/fisiologia , Temperatura Baixa , Aquecimento Global , Plantas , Dispersão de Sementes , Animais , Ecossistema , Europa (Continente) , Voo Animal , Mar Mediterrâneo
9.
Zoology (Jena) ; 147: 125929, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34091244

RESUMO

Coracias benghalensis, commonly known as Indian Roller, a subtropical seasonally breeding bird native to Prayagraj (25° 28' N, 81° 54' E), U.P., India, exhibits a specific rolling behavior (an ornate sexual display) to attract the female for courtship. We hypothesized that the emergence of the seasonal rolling behavior of C. benghalensis would coincide with seasonal neuronal morphology changes in the dorsomedial hippocampus (DMH) area of the hippocampal complex (HCC). To test this hypothesis, the present study aimed to reveal qualitative and quantitative changes in neuronal plasticity in various neuronal classes of DMH across the breeding (pre-breeding and breeding) and the non-breeding (quiescent and regression) phases of the reproductive cycle of C. benghalensis. Plasticity in the morphology of four neuronal types (unipolar, bipolar, pyramidal, and multipolar) in the DMH area of HCC during the breeding and the non-breeding phases was characterized by using Golgi-Colonnier staining for identification and characterization of neuronal morphology. As compared to the quiescent phase, a significant increase of soma diameter, dendritic field, dendritic thickness, length of spine neck, spine head diameter, number of visible spines, and spine density in all four types of neurons was observed during the breeding phase. In contrast, significant decreases were observed during the bird's non-breeding phase compared to the breeding phase. This study concludes that during the breeding phase of C. benghalensis, neuronal arborization was substantially increased in DMH, suggesting an enhanced capability for circuit plasticity possibly underlying rolling behavior. Our study establishes seasonal plasticity in DMH and will serve as a novel model for future studies investigating the molecular, physiological, and cellular mechanisms underlying complex, yet stereotyped, sensorimotor behavior.


Assuntos
Aves/anatomia & histologia , Hipocampo/citologia , Plasticidade Neuronal/fisiologia , Estações do Ano , Comportamento Sexual Animal/fisiologia , Animais , Aves/fisiologia , Masculino
10.
Zoology (Jena) ; 147: 125941, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34126327

RESUMO

Flamingos inhabit specialized habitats and breed in large colonies, building their nests on islands that limit the access of terrestrial predators. Many aspects of their uropygial gland are still unknown. The uropygial gland, a sebaceous organ exclusive to birds, shares some histological features among species such as the presence of a capsule, adenomers with stratified epithelium and secondary and primary chambers. We found that the uropygial gland of the Chilean Flamingo (Phoenicopterus chilensis) displays most of these characteristics but lacks a primary storage chamber. This absence may be an adaptation to their aquatic environment. The uropygial secretion of this species has a variety of glycoconjugates while its lipid moiety is largely dominated by waxes and minor amounts of triacylglycerols and fatty acids. Mass spectrometry analysis of the preen wax showed branched fatty acids of varied chain length and unbranched fatty alcohols, resulting in a complex mixture of wax esters and no differences between sexes were observed. The glycoconjugates present in the preen secretion could play a role as antimicrobial molecules, as suggested for other bird species, while the absence of diester waxes in flamingos might be related with their nesting habits and limited exposure to predation. Our results were evaluated according to physiological and ecological aspects of the flamingo's biology.


Assuntos
Estruturas Animais/fisiologia , Aves/fisiologia , Secreções Corporais/química , Estruturas Animais/anatomia & histologia , Animais , Secreções Corporais/fisiologia , Feminino , Masculino , Tamanho do Órgão , Especificidade da Espécie
11.
Commun Biol ; 4(1): 503, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-33958700

RESUMO

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.


Assuntos
Aves/fisiologia , Encéfalo/anatomia & histologia , Mamíferos/fisiologia , Neurônios/citologia , Bocejo , Animais , Aves/anatomia & histologia , Encéfalo/fisiologia , Mamíferos/anatomia & histologia , Neurônios/fisiologia , Tamanho do Órgão
12.
Nat Commun ; 12(1): 3029, 2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-34031384

RESUMO

Natural sensory environments, despite strong potential for structuring systems, have been neglected in ecological theory. Here, we test the hypothesis that intense natural acoustic environments shape animal distributions and behavior by broadcasting whitewater river noise in montane riparian zones for two summers. Additionally, we use spectrally-altered river noise to explicitly test the effects of masking as a mechanism driving patterns. Using data from abundance and activity surveys across 60 locations, over two full breeding seasons, we find that both birds and bats avoid areas with high sound levels, while birds avoid frequencies that overlap with birdsong, and bats avoid higher frequencies more generally. We place 720 clay caterpillars in willows, and find that intense sound levels decrease foraging behavior in birds. For bats, we deploy foraging tests across 144 nights, consisting of robotic insect-wing mimics, and speakers broadcasting bat prey sounds, and find that bats appear to switch hunting strategies from passive listening to aerial hawking as sound levels increase. Natural acoustic environments are an underappreciated niche axis, a conclusion that serves to escalate the urgency of mitigating human-created noise.


Assuntos
Acústica , Comportamento Animal , Aves/fisiologia , Quirópteros/fisiologia , Rios , Animais , Percepção Auditiva , Ecolocação , Humanos , Insetos , Mariposas/fisiologia , Ruído , Comportamento Predatório , Som
13.
Science ; 372(6542): 601-609, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33958471

RESUMO

Reptiles, including birds, exhibit a range of behaviorally relevant adaptations that are reflected in changes to the structure of the inner ear. These adaptations include the capacity for flight and sensitivity to high-frequency sound. We used three-dimensional morphometric analyses of a large sample of extant and extinct reptiles to investigate inner ear correlates of locomotor ability and hearing acuity. Statistical analyses revealed three vestibular morphotypes, best explained by three locomotor categories-quadrupeds, bipeds and simple fliers (including bipedal nonavialan dinosaurs), and high-maneuverability fliers. Troodontids fall with Archaeopteryx among the extant low-maneuverability fliers. Analyses of cochlear shape revealed a single instance of elongation, on the stem of Archosauria. We suggest that this transformation coincided with the origin of both high-pitched juvenile location, alarm, and hatching-synchronization calls and adult responses to them.


Assuntos
Adaptação Fisiológica , Evolução Biológica , Dinossauros/anatomia & histologia , Dinossauros/fisiologia , Orelha Interna/anatomia & histologia , Locomoção , Vocalização Animal/fisiologia , Animais , Aves/anatomia & histologia , Aves/classificação , Aves/fisiologia , Dinossauros/classificação , Voo Animal/fisiologia , Audição/fisiologia , Filogenia
14.
Science ; 372(6543): 733-737, 2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-33986179

RESUMO

Assessing deep-time mechanisms affecting the assembly of ecological networks is key to understanding biodiversity changes on broader time scales. We combined analyses of diversification rates with interaction network descriptors from 468 bird species belonging to 29 seed dispersal networks to show that bird species that contribute most to the network structure of plant-frugivore interactions belong to lineages that show higher macroevolutionary stability. This association is stronger in warmer, wetter, less seasonal environments. We infer that the macroevolutionary sorting mechanism acts through the regional pool of species by sorting species on the basis of the available relative differences in diversification rates, rather than absolute rates. Our results illustrate how the interplay between interaction patterns and diversification dynamics may shape the organization and long-term dynamics of ecological networks.


Assuntos
Biodiversidade , Evolução Biológica , Aves/fisiologia , Ecossistema , Dispersão de Sementes , Animais , Aves/classificação , Aves/genética , Clima , Meio Ambiente , Extinção Biológica , Comportamento Alimentar , Frutas , Especiação Genética , Filogenia
15.
PLoS One ; 16(5): e0250363, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33979330

RESUMO

Bird call libraries are difficult to collect yet vital for bio-acoustics studies. A potential solution is citizen science labelling of calls. However, acoustic annotation techniques are still relatively undeveloped and in parallel, citizen science initiatives struggle with maintaining participant engagement, while increasing efficiency and accuracy. This study explores the use of an under-utilised and theoretically engaging and intuitive means of sound categorisation: onomatopoeia. To learn if onomatopoeia was a reliable means of categorisation, an online experiment was conducted. Participants sourced from Amazon mTurk (N = 104) ranked how well twelve onomatopoeic words described acoustic recordings of ten native Australian bird calls. Of the ten bird calls, repeated measures ANOVA revealed that five of these had single descriptors ranked significantly higher than all others, while the remaining calls had multiple descriptors that were rated significantly higher than others. Agreement as assessed by Kendall's W shows that overall, raters agreed regarding the suitability and unsuitability of the descriptors used across all bird calls. Further analysis of the spread of responses using frequency charts confirms this and indicates that agreement on which descriptors were unsuitable was pronounced throughout, and that stronger agreement of suitable singular descriptions was matched with greater rater confidence. This demonstrates that onomatopoeia may be reliably used to classify bird calls by non-expert listeners, adding to the suite of methods used in classification of biological sounds. Interface design implications for acoustic annotation are discussed.


Assuntos
Ciência do Cidadão , Som , Vocalização Animal/fisiologia , Acústica , Animais , Percepção Auditiva/fisiologia , Austrália , Aves/fisiologia
16.
Zoo Biol ; 40(4): 352-359, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33861879

RESUMO

Despite the fact that saddle-billed storks (SBS) are housed in zoos around the world, few successful hatches have been recorded. At Disney's Animal Kingdom® we conducted observations on two pairs of SBS during multiple reproductive periods to assess the relative strength of their pair-bonds and their reproductive success. We accomplished this through observations of rates of social behaviors, such as wing displays and aggression, rates of nest construction, time on and near the nest, and egg production. We determined that one pair was more successful than the other because it produced and incubated eggs during all breeding seasons. We found that the male from this more successful pairing displayed higher rates of nest presence, nest construction, and time on the nest than all other individuals. The more successful pairing also spent more time in close proximity than the less successful pair. During incubation, the male and female from the more successful pair spent similar amounts of time at the nest and incubating the eggs, but this pair never successfully hatched an egg during our study period. Ultimately, our results suggest that the pair-bond between the more successful pair was stronger than that of the other pair because they spent more time in close proximity and performed higher rates of nesting behaviors. This study highlights the lack of understanding of the factors that lead to successful SBS pairings in zoos, and emphasizes the need for future studies of their nesting behavior and pair compatibility to increase reproductive success.


Assuntos
Animais de Zoológico , Aves/fisiologia , Abrigo para Animais , Estações do Ano , Comportamento Sexual Animal/fisiologia , Animais , Feminino , Masculino , Fatores de Tempo
17.
Phys Rev Lett ; 126(11): 114501, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33798375

RESUMO

We demonstrate flow rectification, valveless pumping, or alternating to direct current (AC-to-DC) conversion in macroscale fluidic networks with loops. Inspired by the unique anatomy of bird lungs and the phenomenon of directed airflow throughout the respiration cycle, we hypothesize, test, and validate that multiloop networks exhibit persistent circulation or DC flows when subject to oscillatory or AC forcing at high Reynolds numbers. Experiments reveal that disproportionately stronger circulation is generated for higher frequencies and amplitudes of the imposed oscillations, and this nonlinear response is corroborated by numerical simulations. Visualizations show that flow separation and vortex shedding at network junctions serve the valving function of directing current with appropriate timing in the oscillation cycle. These findings suggest strategies for controlling inertial flows through network topology and junction connectivity.


Assuntos
Aves/fisiologia , Pulmão/fisiologia , Modelos Biológicos , Animais , Aves/anatomia & histologia , Simulação por Computador , Pulmão/anatomia & histologia , Modelos Anatômicos , Respiração
18.
Zoolog Sci ; 38(2): 162-169, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33812355

RESUMO

Pesticide use is known to have a negative impact on the habitat use of birds. The decomposition of residual pesticides causes a drastic decrease in the biomass of wildlife food sources, indirectly affecting the ecosystem. In this study, we investigated the effects of pesticide use on the distributions of grey herons (Ardea cinerea) and great egrets (Ardea alba) in rice fields in the Republic of Korea. From early May to mid-June in 2015 and 2016, we recorded the abundance of these birds and their prey (loaches, other fish, tadpoles, and benthic invertebrates) and investigated their dependence on rice agricultural practices (eco-friendly vs conventional) and field types (harrowed, plowed, or transplanted). We found that both grey herons and great egrets preferentially used transplanted fields. Grey herons were observed more in conventional rice fields, while great egrets were observed more in eco-friendly rice fields. This may be driven by the distribution of their preferred prey types; we observed a higher density of tadpoles (the prey type favored by grey herons) in conventional fields and a higher density of loaches (the preferred prey of great egrets) in eco-friendly fields. Pesticides drive these patterns both directly and indirectly; pesticide use in conventional rice fields directly suppresses the abundance of loaches, which frees the tadpole population from predation pressures and indirectly boosts their abundance in conventional rice fields. Our findings suggest that the distributions of grey herons and great egrets vary depending on food availability and are directly and indirectly influenced by pesticide use.


Assuntos
Aves/fisiologia , Cipriniformes/fisiologia , Oryza , Praguicidas/toxicidade , Agricultura , Animais , Ecossistema , Comportamento Alimentar , República da Coreia
19.
Zootaxa ; 4950(2): zootaxa.4950.2.8, 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33903443

RESUMO

Many genus-level changes to the classification of Trochilini were enacted in Stiles et al. (2017b). We have since found that two further genera therein emended each require replacement names. The first of these requiring a replacement name is Uranomitra Reichenbach, 1854 [March], which is herewith interpreted as an additional synonym of Saucerottia Bonaparte, 1850, along with its junior synonym Cyanomyia Bonaparte, 1854a [May]. We show that both must have the same type species, as originally designated, Trochilus quadricolor Vieillot, 1822 = Ornismya cyanocephala Lesson, 1829. The second case in which a replacement name is required is Leucolia Mulsant E. Verreaux, 1866, herewith interpreted as an additional synonym of Leucippus Bonaparte, 1850, with the same type species, Trochilus fallax Bourcier, 1843. We herein propose replacement names for both Uranomitra and Leucolia.


Assuntos
Aves , Animais , Aves/classificação , Aves/fisiologia , Classificação
20.
PLoS One ; 16(4): e0249826, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33909647

RESUMO

Billions of birds fatally collide with human-made structures each year. These mortalities have consequences for population viability and conservation of endangered species. This source of human-wildlife conflict also places constraints on various industries. Furthermore, with continued increases in urbanization, the incidence of collisions continues to increase. Efforts to reduce collisions have largely focused on making structures more visible to birds through visual stimuli but have shown limited success. We investigated the efficacy of a multimodal combination of acoustic signals with visual cues to reduce avian collisions with tall structures in open airspace. Previous work has demonstrated that a combination of acoustic and visual cues can decrease collision risk of birds in captive flight trials. Extending to field tests, we predicted that novel acoustic signals would combine with the visual cues of tall communication towers to reduce collision risk for birds. We broadcast two audible frequency ranges (4 to 6 and 6 to 8 kHz) in front of tall communication towers at locations in the Atlantic migratory flyway of Virginia during annual migration and observed birds' flight trajectories around the towers. We recorded an overall 12-16% lower rate of general bird activity surrounding towers during sound treatment conditions, compared with control (no broadcast sound) conditions. Furthermore, in 145 tracked "at-risk" flights, birds reduced flight velocity and deflected flight trajectories to a greater extent when exposed to the acoustic stimuli near the towers. In particular, the 4 to 6 kHz stimulus produced the greater effect sizes, with birds altering flight direction earlier in their trajectories and at larger distances from the towers, perhaps indicating that frequency range is more clearly audible to flying birds. This "acoustic lighthouse" concept reduces the risk of collision for birds in the field and could be applied to reduce collision risk associated with many human-made structures, such as wind turbines and tall buildings.


Assuntos
Estimulação Acústica/métodos , Migração Animal , Aves/fisiologia , Arquitetura de Instituições de Saúde/métodos , Som , Comportamento Espacial , Animais , Percepção Auditiva , Sinais (Psicologia) , Estimulação Luminosa , Percepção Visual
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