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1.
Sci Rep ; 11(1): 17649, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34480051

RESUMO

The ubiquitous activity of humans is a fundamental feature of urban environments affecting local wildlife in several ways. Testing the influence of human disturbance would ideally need experimental approach, however, in cities, this is challenging at relevant spatial and temporal scales. Thus, to better understand the ecological effects of human activity, we exploited the opportunity that the city-wide lockdowns due to the COVID-19 pandemic provided during the spring of 2020. We assessed changes in reproductive success of great tits (Parus major) at two urban habitats affected strikingly differently by the 'anthropause', and at an unaffected forest site. Our results do not support that urban great tits benefited from reduced human mobility during the lockdown. First, at one of our urban sites, the strongly (- 44%) reduced human disturbance in 2020 (compared to a long-term reference period) did not increase birds' reproductive output relative to the forest habitat where human disturbance was low in all years. Second, in the other urban habitat, recreational human activity considerably increased (+ 40%) during the lockdown and this was associated with strongly reduced nestling body size compared to the pre-COVID reference year. Analyses of other environmental factors (meteorological conditions, lockdown-induced changes in air pollution) suggest that these are not likely to explain our results. Our study supports that intensified human disturbance can have adverse fitness consequences in urban populations. It also highlights that a few months of 'anthropause' is not enough to counterweight the detrimental impacts of urbanization on local wildlife populations.


Assuntos
COVID-19 , Ecossistema , Quarentena , Reprodução/fisiologia , SARS-CoV-2 , Aves Canoras/fisiologia , Animais , COVID-19/epidemiologia , COVID-19/prevenção & controle , Cidades/epidemiologia , Feminino , Humanos , Masculino
2.
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
3.
Science ; 372(6542): 646-648, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33958477

RESUMO

Billions of nocturnally migrating songbirds fly across oceans and deserts on their annual journeys. Using multisensor data loggers, we show that great reed warblers (Acrocephalus arundinaceus) regularly prolong their otherwise strictly nocturnal flights into daytime when crossing the Mediterranean Sea and the Sahara Desert. Unexpectedly, when prolonging their flights, they climbed steeply at dawn, from a mean of 2394 meters above sea level to reach extreme cruising altitudes (mean 5367 and maximum 6267 meters above sea level) during daytime flights. This previously unknown behavior of using exceedingly high flight altitudes when migrating during daytime could be caused by diel variation in ambient temperature, winds, predation, vision range, and solar radiation. Our finding of this notable behavior provides new perspectives on constraints in bird flight and might help to explain the evolution of nocturnal migration.


Assuntos
Altitude , Migração Animal/fisiologia , Voo Animal/fisiologia , Fotoperíodo , Aves Canoras/fisiologia , África do Norte , Animais , Mar Mediterrâneo , Vento
4.
Physiol Biochem Zool ; 94(3): 188-198, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33852373

RESUMO

AbstractThe high energetic costs of both migration and reproduction and the physiological changes to support these costs suggest that these life-history stages should be compartmentalized with little overlap between stages. In contrast, previous studies have shown that male birds can initiate reproductive development during migration before arrival on the breeding grounds with increases in plasma testosterone levels and testis size. However, sex differences in seasonal gonadal function are now recognized as profound, and few studies to date have shown that females can initiate the costly, but critical, estrogen-dependent final stages of gonadal maturation and changes in liver function (yolk precursor synthesis, vitellogenesis) while on migration. Here, we show that female yellow warblers (Setophaga petechia) arrive on the breeding grounds with elevated plasma triglyceride levels compared with males. Some females had plasma triglyceride levels of 5-7 mmol L-1, suggesting that they arrived in a relatively advanced stage of yolk precursor production. Furthermore, we show that females that arrived with higher plasma triglyceride levels took less time to initiate their first clutch. Adaptive plasticity in the timing of the transition from a migratory to a reproductive physiology might help migrant birds buffer against a mismatch between timing of arrival and conditions on the breeding grounds and allow them to advance timing of breeding to maximize breeding productivity.


Assuntos
Migração Animal/fisiologia , Reprodução/fisiologia , Estações do Ano , Aves Canoras/fisiologia , Animais , Feminino , Masculino , Aves Canoras/sangue , Triglicerídeos/sangue
5.
Nat Commun ; 12(1): 1968, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33785751

RESUMO

Wireless battery free and fully implantable tools for the interrogation of the central and peripheral nervous system have quantitatively expanded the capabilities to study mechanistic and circuit level behavior in freely moving rodents. The light weight and small footprint of such devices enables full subdermal implantation that results in the capability to perform studies with minimal impact on subject behavior and yields broad application in a range of experimental paradigms. While these advantages have been successfully proven in rodents that move predominantly in 2D, the full potential of a wireless and battery free device can be harnessed with flying species, where interrogation with tethered devices is very difficult or impossible. Here we report on a wireless, battery free and multimodal platform that enables optogenetic stimulation and physiological temperature recording in a highly miniaturized form factor for use in songbirds. The systems are enabled by behavior guided primary antenna design and advanced energy management to ensure stable optogenetic stimulation and thermography throughout 3D experimental arenas. Collectively, these design approaches quantitatively expand the use of wireless subdermally implantable neuromodulation and sensing tools to species previously excluded from in vivo real time experiments.


Assuntos
Neuroestimuladores Implantáveis , Fenômenos Fisiológicos do Sistema Nervoso , Optogenética/instrumentação , Aves Canoras/fisiologia , Telemetria/instrumentação , Tecnologia sem Fio/instrumentação , Animais , Encéfalo/fisiologia , Optogenética/métodos , Nervos Periféricos/fisiologia , Reprodutibilidade dos Testes , Telemetria/métodos
6.
PLoS One ; 16(2): e0247318, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33617585

RESUMO

Dams and reservoirs alter natural water flow regimes with adverse effects on natural ecosystems. Quantifying and reducing these effects are important as global demands for energy and water, and the number of dams and reservoir, increase. However, costs and logistic constraints typically preclude experimental assessment of reservoir effects on the environment. We developed a stochastic individual-based model (IBM), parameterized using empirical data, to estimate the annual productivity of yellow warblers that breed in riparian habitat within the footprint of the Arrow Lakes Reservoir in British Columbia, Canada. The IBM incorporated information on breeding phenology, nest site selection, brood parasitism, daily nest survival, re-nesting probabilities and post-fledging survival. We used the IBM to estimate the effect of four different water management scenarios on annual productivity. We found that the IBM accurately estimated average nest success (0.39 ± 0.10 SD), the proportion of females that produced at least one fledgling during a breeding season (0.56 ± 0.11), and annual fledging success (2.06 ± 0.43) under current conditions. The IBM estimated that reservoir operations currently reduce the annual productivity of this population by 37%, from an average of 1.62 to 1.06 independent young/female. Delaying when reservoir water levels reach 435m asl (the minimum elevation occupied by yellow warblers) by approximately 2 weeks was predicted to increase annual productivity to 1.44 independent young/female. The standardized effect on annual productivity of reducing the maximum elevation of the reservoir so that yellow warbler habitat is not inundated (Cohen's d = 1.52) or delaying when water is stored (Cohen's d = 0.83) was primarily driven by inundation effects on post-fledging survival. Reservoir operation effects on breeding birds will be species specific, but this IBM can easily be modified to allow the environmental impacts on the entire breeding bird community to be incorporated into water management decisions.


Assuntos
Reprodução/fisiologia , Aves Canoras/fisiologia , Água/química , Animais , Colúmbia Britânica , Ecossistema , Meio Ambiente , Feminino , Masculino , Comportamento de Nidação/fisiologia , Estações do Ano
7.
Sci Rep ; 11(1): 1197, 2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33441920

RESUMO

Airports can affect birds by hindering acoustic communication. Here, we investigated the impacts of aircraft events on vocal behavior in wood thrush (Hylocichla mustelina) breeding one mile from an airport in Ithaca, NY, USA. We identified the number of wood thrush songs between 0500 and 0800 h at various distances from the airport and on days with various morning flight schedules. We also analyzed the number of sites from which birds sang during the peak of aircraft events (proxy of number of wood thrush). We found that birds sang more from 0600 to 0640 h when there were aircraft events during this period. This increased vocal behavior is likely explained by increased song output per individual wood thrush, rather than more wood thrush vocalizing. Increased song rate may negatively affect wood thrush fitness through increased energetic demands and/or time tradeoffs with other important behaviors, such as foraging. Identifying the noise thresholds associated with fitness costs (if any) and how different behavioral strategies (i.e. changing the pattern of vocalizations) may allow individuals to evade these costs would be useful for establishing conservation policy in breeding habitats used by passerines, such as the wood thrush.


Assuntos
Aves Canoras/fisiologia , Aeronaves , Animais , Ecossistema , Ruído/efeitos adversos
8.
Am Nat ; 197(1): 93-110, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33417521

RESUMO

AbstractAdaptive topography is a central concept in evolutionary biology, describing how the mean fitness of a population changes with gene frequencies or mean phenotypes. We use expected population size as a quantity to be maximized by natural selection to show that selection on pairwise combinations of reproductive traits of collared flycatchers caused by fluctuations in population size generated an adaptive topography with distinct peaks often located at intermediate phenotypes. This occurred because r- and K-selection made phenotypes favored at small densities different from those with higher fitness at population sizes close to the carrying capacity K. Fitness decreased rapidly with a delay in the timing of egg laying, with a density-dependent effect especially occurring among early-laying females. The number of fledglings maximizing fitness was larger at small population sizes than when close to K. Finally, there was directional selection for large fledglings independent of population size. We suggest that these patterns can be explained by increased competition for some limiting resources or access to favorable nest sites at high population densities. Thus, r- and K-selection based on expected population size as an evolutionary maximization criterion may influence life-history evolution and constrain the selective responses to changes in the environment.


Assuntos
Densidade Demográfica , Aves Canoras/genética , Aves Canoras/fisiologia , Animais , Evolução Biológica , Feminino , Aptidão Genética , Masculino , Oviposição/fisiologia , Seleção Genética , Suécia
9.
Zool Res ; 42(2): 217-220, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33496092

RESUMO

Recent studies have examined the cost of raising parasitic cuckoos and highlighted the importance of "no extra cost" in explaining the low levels of defense in hosts. To clarify the reasons for parasitization in typical hosts, we present a simple model to explore the immediate and future costs of parasitism in shaping the evolution of defense behavior in hosts. Our results suggest that any cost of parasitization is maladaptive to the host and learned egg recognition is always favored to overcome these costs. Furthermore, although facing a potential cost of mis-imprinting, learned nestling recognition may still evolve when there is a non-zero immediate cost from raising a parasitic nestling. Therefore, we contend that "no extra cost" does not provide sufficient evidence to explain the low levels of defense behavior in hosts per se.


Assuntos
Metabolismo Energético/fisiologia , Comportamento de Nidação/fisiologia , Aves Canoras/fisiologia , Aves Canoras/parasitologia , Animais , Evolução Biológica , Feminino , Interações Hospedeiro-Parasita/fisiologia , Comportamento Materno/fisiologia , Oviposição/fisiologia , Especificidade da Espécie
10.
PLoS One ; 16(1): e0236536, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33444336

RESUMO

Oxygen, hydrogen, carbon and nitrogen stable isotopes were measured on a comprehensive sampling of feathers from two spring Hooded Warblers (Setophaga citrina) in Texas to evaluate isotopic variability between feathers and during molt. Isotopic homogeneity within each bird was found across all four isotopic systems, supporting the hypothesis that molt in these neotropical migrants is fully completed on the breeding grounds. This homogeneity suggests that the isotopic composition of a single feather is may be representative of the whole songbird. However, each bird was found to have one or two outlier feathers, which could signify regrowth of lost feathers after prebasic molt.


Assuntos
Plumas/química , Plumas/fisiologia , Isótopos/química , Passeriformes/fisiologia , Aves Canoras/fisiologia , Migração Animal/fisiologia , Animais , Geografia/métodos , Muda/fisiologia , Estações do Ano , Texas
11.
J Neurosci ; 41(1): 73-88, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33177068

RESUMO

The capacity for sensory systems to encode relevant information that is invariant to many stimulus changes is central to normal, real-world, cognitive function. This invariance is thought to be reflected in the complex spatiotemporal activity patterns of neural populations, but our understanding of population-level representational invariance remains coarse. Applied topology is a promising tool to discover invariant structure in large datasets. Here, we use topological techniques to characterize and compare the spatiotemporal pattern of coactive spiking within populations of simultaneously recorded neurons in the secondary auditory region caudal medial neostriatum of European starlings (Sturnus vulgaris). We show that the pattern of population spike train coactivity carries stimulus-specific structure that is not reducible to that of individual neurons. We then introduce a topology-based similarity measure for population coactivity that is sensitive to invariant stimulus structure and show that this measure captures invariant neural representations tied to the learned relationships between natural vocalizations. This demonstrates one mechanism whereby emergent stimulus properties can be encoded in population activity, and shows the potential of applied topology for understanding invariant representations in neural populations.SIGNIFICANCE STATEMENT Information in neural populations is carried by the temporal patterns of spikes. We applied novel mathematical tools from the field of algebraic topology to quantify the structure of these temporal patterns. We found that, in a secondary auditory region of a songbird, these patterns reflected invariant information about a learned stimulus relationship. These results demonstrate that topology provides a novel approach for characterizing neural responses that is sensitive to invariant relationships that are critical for the perception of natural stimuli.


Assuntos
Córtex Auditivo/fisiologia , Fenômenos Eletrofisiológicos , Aves Canoras/fisiologia , Estorninhos/fisiologia , Estimulação Acústica , Algoritmos , Animais , Vias Auditivas/citologia , Vias Auditivas/fisiologia , Condicionamento Operante , Potenciais Evocados Auditivos/fisiologia , Feminino , Masculino , Modelos Neurológicos , Neostriado/citologia , Neostriado/fisiologia , Neurônios/fisiologia , Vocalização Animal/fisiologia
12.
Proc Biol Sci ; 287(1941): 20202482, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33323080

RESUMO

Many animals produce coordinated signals, but few are more striking than the elaborate male-female vocal duets produced by some tropical songbirds. Yet, little is known about the factors driving the extreme levels of vocal coordination between mated pairs in these taxa. We examined evolutionary patterns of duet coordination and their potential evolutionary drivers in Neotropical wrens (Troglodytidae), a songbird family well known for highly coordinated duets. Across 23 wren species, we show that the degree of coordination and precision with which pairs combine their songs into duets varies by species. This includes some species that alternate their song phrases with exceptional coordination to produce rapidly alternating duets that are highly consistent across renditions. These highly coordinated, consistent duets evolved independently in multiple wren species. Duet coordination and consistency are greatest in species with especially long breeding seasons, but neither duet coordination nor consistency are correlated with clutch size, conspecific abundance or vegetation density. These results suggest that tightly coordinated duets play an important role in mediating breeding behaviour, possibly by signalling commitment or coalition of the pair to mates and other conspecifics.


Assuntos
Aves Canoras/fisiologia , Vocalização Animal , Animais , Evolução Biológica , Feminino , Masculino , Ligação do Par , Reprodução
13.
Proc Biol Sci ; 287(1939): 20201878, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33234077

RESUMO

Early independence from parents is a critical period where social information acquired vertically may become outdated, or conflict with new information. However, across natural populations, it is unclear if newly independent young persist in using information from parents, or if group-level effects of conformity override previous behaviours. Here, we test if wild juvenile hihi (Notiomystis cincta, a New Zealand passerine) retain a foraging behaviour from parents, or if they change in response to the behaviour of peers. We provided feeding stations to parents during chick-rearing to seed alternative access routes, and then tracked their offspring's behaviour. Once independent, juveniles formed mixed-treatment social groups, where they did not retain preferences from their time with parents. Instead, juvenile groups converged over time to use one access route- per group, and juveniles that moved between groups switched to copy the locally favoured option. Juvenile hihi did not copy specific individuals, even if they were more familiar with the preceding bird. Our study shows that early social experiences with parents affect initial foraging decisions, but social environments encountered later on can update transmission of arbitrary behaviours. This suggests that conformity may be widespread in animal groups, with potential cultural, ecological and evolutionary consequences.


Assuntos
Comportamento Alimentar/fisiologia , Aves Canoras/fisiologia , Animais , Aprendizagem/fisiologia , Nova Zelândia , Passeriformes/fisiologia , Comportamento Social , Meio Social
14.
Sci Rep ; 10(1): 20330, 2020 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-33230166

RESUMO

Nesting birds can act as thermal ecosystem engineers by providing warm habitats that may attract arthropods to colonise the nest structure. This cohabitation of birds and nest-dwelling invertebrates may foster symbiotic relationships between them, but evidence is lacking. We investigated whether ants are attracted to bird nests by the heat generated by the hosts, and/or the nests' structural insulation properties, to raise their broods (larvae and/or pupae) in advantageous thermal conditions. We found that the endothermic activity of birds within their nests created 'heat islands', with thermal conditions potentially promoting the survival and development of ant larvae in cool environments. We experimentally confirmed that the presence of heat within bird nests, and not the structure itself, attracted the ants to colonise the nests. As ants might benefit from exploiting warm bird nests, this may be a previously overlooked commensal, mutualistic or parasitic relationship which may be ecologically significant and globally widespread among various nesting birds and reproducing ants. Similar interspecific interactions may exist with other arthropods that reproduce in avian and mammalian nests. Further research is needed to reveal the nature of these relationships between such taxa, and to understand the role of warm-blooded animals as thermal ecosystem engineers.


Assuntos
Formigas/fisiologia , Florestas , Temperatura Alta , Comportamento de Nidação/fisiologia , Aves Canoras/fisiologia , Simbiose/fisiologia , Animais , Polônia
15.
Proc Biol Sci ; 287(1936): 20202002, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-33023412

RESUMO

Foragers rely on various cues to assess predation risk. Information theory predicts that high certainty cues should be valued more than low certainty cues. We measured the latency of black-capped chickadees (Poecile atricapillus) to resume feeding during winter in response to cues that conferred different degrees of certainty about current predation risk: a high certainty visual cue (predator mount) and a lower certainty acoustic cue (conspecific mobbing calls), presented either alone or in combination. As predicted, chickadees took longer to resume feeding after the visual than the acoustic cue, and this effect was greatest under conditions of high starvation risk (i.e. low temperatures). Presenting both cues together produced the same foraging delay as the visual cue alone under low starvation risk, but surprisingly, resulted in lower responses under high starvation risk compared to the visual cue alone. We suggest that this may be due to prey using a form of information updating, whereby differences in the timing of perception of acoustic versus visual cues interacts with energetic constraint to shape perceived risk. Although the sequential perception of cues is likely in a range of decision-making contexts, studies manipulating the order in which cues are perceived are needed to test existing models of multimodal cue integration.


Assuntos
Aves Canoras/fisiologia , Vocalização Animal/fisiologia , Acústica , Animais , Percepção Auditiva/fisiologia , Sinais (Psicologia) , Comportamento Predatório , Estações do Ano , Espectrografia do Som
16.
PLoS One ; 15(10): e0241035, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33119633

RESUMO

Anthropogenic noise is an often-overlooked byproduct of urbanization and affects the soundscape in which birds communicate. Previous studies assessing the impact of traffic noise have focused on bird song, with many studies demonstrating the ability of birds to raise song frequency in the presence of low-frequency traffic noise to avoid masking. Less is known about the impact of traffic noise on avian alarm calls, which is surprising given the degree to which predator information within alarm calls may impact fitness. The objective of this study was to assess the impacts of traffic noise on the Black-capped Chickadees (Poecile atricapillus), a small non-migratory songbird with a well-studied and information-rich alarm call. We studied birds at eight locations in Stark County, Ohio, from 15 January to 7 March 2016, and used a taxidermic mount of an Eastern Screech-Owl to elicit alarm calls. In half of the trials, a pre-recorded traffic noise track was also broadcasted at 50 decibels. In noise trials, chickadee calls contained more introductory notes (P < 0.001), more total notes (P < 0.001), were of longer duration (P < 0.001), and had lower introductory and D-note peak frequencies (P = 0.032 and P = 0.041, respectively). No differences were noted in the number of D-notes per call between noise and control trials. Modifying alarm call duration and frequency, without changing the number of D-notes, may be a strategy that chickadees use to convey predator information and to coordinate a threat-appropriate mobbing response when it is not possible to change call type. Our results add to the small, but growing, literature documenting the effects of anthropogenic noise on avian alarm calls, demonstrate the flexibility and complexity of chickadee calls given in response to predators, and may partially explain why chickadees adapt well to urban areas.


Assuntos
Percepção Auditiva/fisiologia , Ruído dos Transportes/efeitos adversos , Aves Canoras/fisiologia , Vocalização Animal/fisiologia , Animais
17.
PLoS Comput Biol ; 16(10): e1008228, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33057332

RESUMO

Animals produce vocalizations that range in complexity from a single repeated call to hundreds of unique vocal elements patterned in sequences unfolding over hours. Characterizing complex vocalizations can require considerable effort and a deep intuition about each species' vocal behavior. Even with a great deal of experience, human characterizations of animal communication can be affected by human perceptual biases. We present a set of computational methods for projecting animal vocalizations into low dimensional latent representational spaces that are directly learned from the spectrograms of vocal signals. We apply these methods to diverse datasets from over 20 species, including humans, bats, songbirds, mice, cetaceans, and nonhuman primates. Latent projections uncover complex features of data in visually intuitive and quantifiable ways, enabling high-powered comparative analyses of vocal acoustics. We introduce methods for analyzing vocalizations as both discrete sequences and as continuous latent variables. Each method can be used to disentangle complex spectro-temporal structure and observe long-timescale organization in communication.


Assuntos
Aprendizado de Máquina não Supervisionado , Vocalização Animal/classificação , Vocalização Animal/fisiologia , Algoritmos , Animais , Quirópteros/fisiologia , Análise por Conglomerados , Biologia Computacional , Bases de Dados Factuais , Humanos , Camundongos , Aves Canoras/fisiologia , Espectrografia do Som , Voz/fisiologia
18.
Science ; 370(6516): 575-579, 2020 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-32972991

RESUMO

Actions taken to control the coronavirus disease 2019 (COVID-19) pandemic have conspicuously reduced motor vehicle traffic, potentially alleviating auditory pressures on animals that rely on sound for survival and reproduction. Here, by comparing soundscapes and songs across the San Francisco Bay Area before and during the recent statewide shutdown, we evaluated whether a common songbird responsively exploited newly emptied acoustic space. We show that noise levels in urban areas were substantially lower during the shutdown, characteristic of traffic in the mid-1950s. We also show that birds responded by producing higher performance songs at lower amplitudes, effectively maximizing communication distance and salience. These findings illustrate that behavioral traits can change rapidly in response to newly favorable conditions, indicating an inherent resilience to long-standing anthropogenic pressures such as noise pollution.


Assuntos
Infecções por Coronavirus/epidemiologia , Ruído , Pneumonia Viral/epidemiologia , Aves Canoras/fisiologia , Vocalização Animal , Acústica , Animais , Betacoronavirus , COVID-19 , Veículos Automotores , Pandemias , SARS-CoV-2 , São Francisco
19.
Sci Rep ; 10(1): 15794, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978454

RESUMO

The primary sensory molecule underlying light-dependent magnetic compass orientation in migratory birds has still not been identified. The cryptochromes are the only known class of vertebrate proteins which could mediate this mechanism in the avian retina. Cryptochrome 4 of the night-migratory songbird the European robin (Erithacus rubecula; erCry4) has several of the properties needed to be the primary magnetoreceptor in the avian eye. Here, we report on the identification of a novel isoform of erCry4, which we named erCry4b. Cry4b includes an additional exon of 29 amino acids compared to the previously described form of Cry4, now called Cry4a. When comparing the retinal circadian mRNA expression pattern of the already known isoform erCry4a and the novel erCry4b isoform, we find that erCry4a is stably expressed throughout day and night, whereas erCry4b shows a diurnal mRNA oscillation. The differential characteristics of the two erCry4 isoforms regarding their 24-h rhythmicity in mRNA expression leads us to suggest that they might have different functions. Based on the 24-h expression pattern, erCry4a remains the more likely cryptochrome to be involved in radical-pair-based magnetoreception, but at the present time, an involvement of erCry4b cannot be excluded.


Assuntos
Migração Animal , Criptocromos/metabolismo , Retina/metabolismo , Aves Canoras/metabolismo , Animais , Orientação , Isoformas de Proteínas , Aves Canoras/fisiologia
20.
Sci Rep ; 10(1): 15888, 2020 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-32985594

RESUMO

The amount of care parents provide to the offspring is complicated by an evolutionary conflict of interest ('sexual conflict') between the two parents. Recent theoretical models suggest that pair coordination of the provisioning may reduce this conflict and increase parent and offspring fitness. Despite empirical studies showing that pair coordination is common in avian species, it remains unclear how environmental and ecological conditions might promote or limit the ability of parents to coordinate care. We compared the level of pair coordination, measured as alternation and synchrony of the nest visits, of house wrens Troglodytes aedon pairs breeding in a rural (10 nests) and a suburban (9 nests) site and investigated how differences in parental behaviours were related to habitat composition, prey abundance and how they ultimately related to reproductive success. We found that parents alternated and synchronized their nest visits more in the rural site compared to the suburban one. The suburban site is characterized by a more fragmented habitat with more coniferous trees and less caterpillar availability. Offspring from the rural site were heavier at fledging than at the suburban site. Taken together, these results suggest that environmental conditions play an important role on the emergence of coordinated parental care and that considering environmental variables is pivotal to assess the fitness consequences of parental strategies.


Assuntos
Ecossistema , Comportamento Materno/fisiologia , Comportamento de Nidação/fisiologia , Comportamento Paterno/fisiologia , Aves Canoras/fisiologia , Animais , Comportamento Animal/fisiologia
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