Reintroductions are increasingly used as a tool to bolster declining populations of birds, but the potential for communication barriers arising from learned vocal variation between introduced and wild populations has rarely been considered. The critically endangered great green macaw, Ara ambiguus, is one such declining species, but it is currently unknown whether there is vocal variation in adult contact calls among geographically isolated populations. Furthermore, variation in nestling calls among populations has never been investigated and could offer insight into how the nestling social environment shapes the formation of dialects. We investigated whether adult and nestling great green macaws show among-population variation in the acoustic structure of their calls by recording vocalizations in one wild, one captive and one reintroduced population in Costa Rica. We assessed acoustic similarity among the three populations by measuring 26 parameters from the spectrogram of each call and performing spectrographic cross-correlation. We tested for population differences in the acoustic structure of adult and nestling calls using linear mixed models and Mantel tests. Only minimal variation was detected among adult contact calls from the three populations. During mid-development, nestling calls showed variation among populations that may be explained by individual morphological differences and overproduction of call types. Minimal variation later in development may be explained by selective attrition of the vocal repertoire as well as vocal convergence driven by the pressure to form and maintain flocks during adulthood. Investigating adult and nestling calls across isolated populations of threatened parrot species can give insight into how vocal variation develops among populations and when conservation managers should consider vocal differences between released and wild birds during the reintroduction process. (c) 2026 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Migration is challenging for birds, especially juveniles, who experience high mortality rates during migration. The challenge is exacerbated in the Anthropocene, contributing to widespread population declines. Conservation efforts focused on increasing juvenile survival could bolster population recovery. Understanding how age structure of the migrant community shifts throughout migration could inform conservation efforts and future questions of migration ecology. However, it is unknown whether the age structure of the migrant community shifts spatially or temporally during migration. To answer these questions, we first analyzed age-related differences in migration speed and timing of departure during fall migration using 6 567 747 banding encounters, as variability in these components of migration could generate shifts in community demographics. We found widespread differences in migration speed (km d-1) with adults being faster than juveniles in most species, and departure timing differences tied to adult molt. Our analyses revealed shifts in community demographics, with the proportion of juveniles within the community decreasing at northerly latitudes throughout migration. We also determined that demographics have shifted over 53 years, with the proportion of juveniles increasing in the north, and decreasing in the south. Our findings contribute to our knowledge of migration ecology, and our understanding of community shifts over time.

Chronic stress can impair behaviors critical for survival, including cognitive traits such as vocal learning. Budgerigars (Melopsittacus undulatus), a parrot species capable of lifelong vocal plasticity, offer a valuable model for studying how stress affects vocal learning circuitry. Previous research has shown that chronic stress induced by unpredictable environmental disturbances reduces vocal plasticity in captive budgerigars, but the molecular mechanisms underlying this change remain unclear. To investigate physiological and molecular responses to these disturbances, we collected data across weekly timepoints in budgerigars subjected to a protocol of mild, unpredictable disturbances. We measured both baseline and stress-induced circulating corticosterone levels and used qPCR to assess expression of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) mRNA in three brain regions: the magnocellular nucleus of the medial striatum (MMSt), a vocal learning nucleus; the ventral striatum pallidum (VSP), a neighboring striatal region; and the hippocampus, which is involved in stress regulation. Contrary to expectations, there was no statistically significant difference in circulating corticosterone between control and experimental treatments nor among weeks. However, the presence of unpredictable disturbances was associated with significantly reduced GR expression in the MMSt, a region critical for maintaining the stereotypy of learned vocalizations. MR expression in all regions did not differ with treatment or week of sampling. These findings suggest that local downregulation of GR in vocal learning circuitry, rather than systemic hormonal changes, may mediate stress-induced alterations in vocal behavior. This study provides new insight into the neuroendocrine mechanisms by which exposure to unpredictable disturbances affects cognitive function in vocal learners.

Chronic stress affects cognitive function across many domains, including memory, decision making and learning. While the effects of early-life stress on vocal learning in juveniles are well-demonstrated in both humans and songbirds, less is known about how stress experienced by adults affects their ability to learn new vocalizations or the neural substrates that underlie this behavior. We investigated the effects of chronic stress on the production and learning of contact calls, and on the expression of a key learning related gene, FoxP2, in the vocal learning circuit in adult budgerigars (Melopsittacus undulatus), a small parrot with open-ended vocal learning. We induced chronic stress via unpredictable disturbances in the captive environments of nine newly-formed replicate flocks of 4 adult male budgerigars who were previously unfamiliar to each other. We then recorded calling behavior daily and measured weight, breath rate, and baseline and stress response levels of circulating corticosterone weekly. At the end of the experiment brains were collected to examine mRNA and protein levels of the gene FoxP2 in the vocal learning region magnocellular nucleus of the medial striatum (MMSt) using qPCR and immunohistochemistry. Physiological measures of stress consistently showed stronger responses in birds subjected to the highest level of disturbance than those in the medium or baseline control treatments, although only differences in baseline corticosterone were detected among treatments. We used machine learning approaches to map calls onto a shared acoustic space to assess four measures of vocal behavior and learning: vocal output (the number of contact calls produced), vocal diversity (the amount of acoustic space occupied by the calls of an individual), vocal plasticity (the amount of change in acoustic space over time) and vocal convergence (the degree of overlap between an individual's calls and the calls of its group). Birds in the high stress treatment showed higher vocal output and lower vocal plasticity than those in medium stress or baseline control groups, but there were no differences among treatments in vocal diversity or vocal convergence. There were no differences detected among treatments in expression levels of either FoxP2 mRNA or protein, perhaps due to the timing of neural sampling relative to the behavioral measures. These results suggest that, as seen in juvenile learning, chronic stress can negatively impact vocal learning in adults via changes in patterns of circulating corticosterone.

Many birds are migratory, and this life history strategy allows for maximized access to seasonally abundant resources and favorable climates. However, migration exposes birds to threats and stressors, resulting in high mortality during migration. Anthropogenic landscape alterations and climate change have intensified threats, and mass mortality events linked to extreme weather are more common in recent decades. Documenting mass mortality is critical for predicting future occurrences and implementing effective conservation. Here, we describe a mortality event that occurred throughout New Mexico, USA in fall 2020. Carcasses began appearing in the region in mid-August, during a period of extreme heat and drought. Following an extreme cold weather event on September 8–9th, the number of carcasses increased dramatically and expanded throughout the state. In total, we collected 628 carcasses comprising 58 species within Doña Ana and Otero Counties in New Mexico. Necropsy determined emaciation was the cause of death for 74.6% of carcasses. Live birds captured during the period of peak mortality (n = 223) were in similarly poor condition. This event provides a striking example of how multiple types of extreme stressors, in this case widespread drought and unseasonal cold, coincided with a mortality event, indicating a possible synergistic relationship between these factors and the mass mortality. Mortality events are likely to increase in frequency with intensifying climate change. Establishment of networks of biologists and researchers could improve our ability to identify and communicate developing mortality events, organize data collection, and improve understanding of the causes and consequences of mortality.

The world in which birds evolved to migrate has been drastically altered in the Anthropocene by artificial light. Sources of light such as urban centers or bright upward-facing lights attract migrants, altering their behavior, especially during inclement weather, often leading to mortality. Seemingly less extreme sources, such as polemounted floodlighting, ubiquitous throughout much of the world, have received comparatively less study, and migrant responses to such sources are poorly understood. We studied migrant behavior in relation to light at White Sands Missile Range (New Mexico, USA) by recording nocturnal flight calls at sites with and without lights during non-inclement weather. We collected 103,424 h of recordings and detected 2,851,863 calls over three fall migration seasons. We assessed how temporal, weather, and lighting variables explain variability in call rates between light and dark sites, and examined how different taxonomic groups behave in relation to light. Contrary to predictions, call rates were higher at dark sites than at light sites, and this difference was strongest early in the migration season. We found illuminated sites with a greater proportion of shielded lights, or with lights of higher dominant wavelengths (warmer color temperatures), had higher call rates (closely resembling dark sites) than other light sites, indicating that these factors may reduce impact to migrants. Our taxonomic analyses revealed consistent differences in call rate between light and dark sites for warblers, but no difference for most sparrows. Our findings indicate that lights alter behavior, but the use of "bird-friendly" lighting strategies may reduce this impact.

Bats host a wide range of viruses, including several high-profile pathogens of humans and other animals. The COVID-19 pandemic raised the level of concern regarding the risk of spillover of bat-borne viruses to humans and, conversely, human-borne viruses to bats. From August 2020 to July 2021, we conducted viral surveillance on 254 bats from 10 species across urban, periurban, and rural environments in New Mexico, USA. We used a pan-coronavirus RT-PCR to assay rectal swabs and performed metagenomic sequencing on a representative subset of 14 rectal swabs and colon samples. No coronaviruses were detected by either RT-PCR or metagenomic sequencing. However, four novel viruses were identified: an adenovirus (proposed name lacepfus virus, LCPV), an adeno-associated virus (AAV), an astrovirus (AstV), and a genomovirus (GV). LCPV, detected in a big brown bat (Eptesicus fuscus), is more closely related to canine adenoviruses than to other bat adenoviruses, suggesting historical transmission between bats and dogs. All virus-positive bats were either juvenile or adult individuals captured in urban environments; none exhibited obvious clinical signs of disease. Our findings suggest limited or no circulation of enzootic coronaviruses or SARS-CoV-2 in southwestern U.S. bat populations during the study period. The discovery of a genetically distinct adenovirus related to canine adenoviruses highlights the potential for cross-species viral transmission and underscores the value of continued virome surveillance in animals living with and near humans.

BACKGROUND:Vocal learning is a rare, convergent trait that is fundamental to both human speech and birdsong. The Forkhead Box P2 (FOXP2) transcription factor appears necessary for both types of learned signals, as human mutations in FOXP2 result in speech deficits, and disrupting its expression in zebra finches impairs male-specific song learning. In juvenile and adult male finches, striatal FOXP2 mRNA and protein decline acutely within song-dedicated neurons during singing, indicating that its transcriptional targets are also behaviorally regulated. The identities of these targets in songbirds, and whether they differ across sex, development and/or behavioral conditions, are largely unknown. RESULTS:Here we used chromatin immunoprecipitation followed by sequencing (ChIP-Seq) to identify genomic sites bound by FOXP2 in male and female, juvenile and adult, and singing and non-singing birds. Our results suggest robust FOXP2 binding concentrated in putative promoter regions of genes. The number of genes likely to be bound by FOXP2 varied across conditions, suggesting specialized roles of the candidate targets related to sex, age, and behavioral state. We interrogated these binding targets both bioinformatically, with comparisons to previous studies, and biochemically, with immunohistochemistry using an antibody for a putative target gene. Gene ontology analyses revealed enrichment for human speech- and language-related functions in males only, consistent with the sexual dimorphism of song learning in this species. Fewer such targets were found in juveniles relative to adults, suggesting an expansion of this regulatory network with maturation. The fewest speech-related targets were found in the singing condition, consistent with the well-documented singing-driven down-regulation of FOXP2 in the songbird striatum. CONCLUSIONS:Overall, these data provide an initial catalog of the regulatory landscape of FOXP2 in an avian vocal learner, offering dozens of target genes for future study and providing insight into the molecular underpinnings of vocal learning.

Abstract Migratory birds have experienced widespread declines in abundance and face numerous threats. The conservation of migratory species relies in part on improved knowledge of active migration behavior, but this behavior is difficult to study as most birds migrate at night. Flight calls, which are species-specific calls produced by many nocturnal migrants during flight, offer an opportunity to improve our understanding of migration behavior and serve as a tool to monitor populations. Although nocturnal flight call monitoring has been historically limited to small spatial and temporal scales, recent technological advancements have allowed researchers to largely shed these constraints. Despite this expansion, there are many unanswered questions regarding the function of flight calls and the proximate drivers of calling behavior. There are also unaddressed concerns that the methods used to record nocturnal flight calls, as well as other organismal, environmental, and social factors, may bias data in ways that impede (or prohibit) comparisons across time and space. Research that addresses these limitations and potential sources of bias will advance the use of nocturnal flight call monitoring for migratory bird research.

Bird migration involves the movements of billions of individuals but is difficult to study because it occurs primarily at night. We sought to improve our understanding of the methods available to study migration, particularly in understudied regions of western North America. We evaluated 2 methods: weather radar and nocturnal flight call monitoring. We analyzed variability in estimates of migration activity from each method, how estimates relate, and identified factors associated with variation in this relationship. We collected radar and flight call data from southern New Mexico in western North America during the fall migration of 2021 and 2022. Similar studies have occurred in eastern North America, but it is unknown if regional variability alters the relationship between estimates from each method. We found that estimates were positively related across a season, but relationships were variable among nights. Also, we discovered that the strength of the association between methods varied across sites, indicating that local factors may influence acoustic sampling. We determined that variation in acoustic estimates of migration activity was associated with cloud cover, crosswind, date, migrant height, migrant speed, moon illumination, tailwind, and time of night. For radar, we found crosswind, date, migrant height, migrant speed, tailwind, and time of night to be associated with variations in estimates of migration activity. Overall, our findings support those of previous studies from eastern North America and demonstrate that, despite regional differences, estimates from each method are also correlated in western North America. Our findings provide new insight into factors associated with variation in estimates of migration activity from 2 widely used methods and an improved understanding of factors that impact migration behavior. center dot We generated and compared estimates of migration activity quantified by weather radar and acoustic monitoring at 50 and 55 locations at White Sands Missile Range in western North America during the fall migration seasons of 2021 and 2022.center dot We found a strong positive relationship between estimates of migration activity from each method on a seasonal basis, but the relationships varied significantly from night to night.center dot Variability in estimates of migration activity was associated with a variety of factors including cloud cover, crosswind, date, migrant height, migrant speed, moon illumination, and time within the night.center dot Our research corroborates studies conducted in eastern North America which have found positive relationships between estimates of migration activity derived from weather radar and nocturnal flight call monitoring across nights, but not within nights.center dot Additional research into the factors contributing to variability in individual flight calling behavior is needed to develop a more complete understanding of avian migration behavior. La migraci & oacute;n de aves implica los movimientos de miles de millones de individuos, pero es dif & iacute;cil de estudiar porque ocurre principalmente de noche. Buscamos mejorar el entendimiento de los m & eacute;todos disponibles para estudiar la migraci & oacute;n, particularmente en regiones poco estudiadas del oeste de Am & eacute;rica del Norte. Evaluamos dos m & eacute;todos: el radar meteorol & oacute;gico y el monitoreo de llamadas en vuelo nocturnas. Analizamos la variabilidad en las estimaciones de actividad migratoria de cada m & eacute;todo, c & oacute;mo se relacionan las estimaciones, e identificamos factores asociados con la variaci & oacute;n en esta relaci & oacute;n. Colectamos datos de radar y de llamadas en vuelo del sur de Nuevo M & eacute;xico en el oeste de Am & eacute;rica del Norte durante la migraci & oacute;n de oto & ntilde;o de 2021 y 2022. Estudios similares se han realizado en el este de Am & eacute;rica del Norte, pero se desconoce si la variabilidad regional altera la relaci & oacute;n entre las estimaciones de cada m & eacute;todo. Encontramos que las estimaciones estaban positivamente relacionadas a lo largo de la temporada, pero las relaciones variaban entre las noches. Tambi & eacute;n descubrimos que la fuerza de la asociaci & oacute;n entre los m & eacute;todos variaba seg & uacute;n los sitios, indicando que los factores locales pueden influir en el muestreo ac & uacute;stico. Determinamos que la variaci & oacute;n en las estimaciones ac & uacute;sticas de actividad migratoria estaba asociada con la cobertura de nubes, el viento cruzado, la fecha, la altura del migrante, la velocidad del migrante, la iluminaci & oacute;n de la luna, el viento a favor y la hora de la noche. Para el radar, encontramos que el viento cruzado, la fecha, la altura del migrante, la velocidad del migrante, el viento a favor y la hora de la noche estaban asociados con la variaci & oacute;n en las estimaciones de actividad migratoria. En general, nuestros hallazgos respaldan los de estudios previos del este de Am & eacute;rica del Norte y demuestran que, a pesar de las diferencias regionales, las estimaciones de cada m & eacute;todo tambi & eacute;n est & aacute;n correlacionadas en el oeste de Am & eacute;rica del Norte. Nuestros hallazgos brindan una nueva perspectiva sobre los factores asociados con la variaci & oacute;n en las estimaciones de actividad migratoria de dos m & eacute;todos ampliamente utilizados y una mejor comprensi & oacute;n de los factores que afectan el comportamiento migratorio.

Most vocal learning species exhibit an early critical period during which their vocal control neural circuitry facilitates the acquisition of new vocalizations. Some taxa, most notably humans and parrots, retain some degree of neurobehavioral plasticity throughout adulthood, but both the extent of this plasticity and the neurogenetic mechanisms underlying it remain unclear. Differential expression of the transcription factor FoxP2 in both songbird and parrot vocal control nuclei has been identified previously as a key pattern facilitating vocal learning. We hypothesize that the resilience of vocal learning to cognitive decline in open-ended learners will be reflected in an absence of age-related changes in neural FoxP2 expression. We tested this hypothesis in the budgerigar (Melopsittacus undulatus), a small gregarious parrot in which adults converge on shared call types in response to shifts in group membership. We formed novel flocks of 4 previously unfamiliar males belonging to the same age class, either “young adult” (6 mo − 1 year) or “older adult” (≥ 3 year), and then collected audio-recordings over a 20-day learning period to assess vocal learning ability. Following behavioral recording, immunohistochemistry was performed on collected neural tissue to measure FoxP2 protein expression in a parrot vocal learning center, the magnocellular nucleus of the medial striatum (MMSt), and its adjacent striatum. Although older adults show lower vocal diversity (i.e. repertoire size) and higher absolute levels of FoxP2 in the MMSt than young adults, we find similarly persistent downregulation of FoxP2 and equivalent vocal plasticity and vocal convergence in the two age cohorts. No relationship between individual variation in vocal learning measures and FoxP2 expression was detected. We find neural evidence to support persistent vocal learning in the budgerigar, suggesting resilience to aging in the open-ended learning program of this species. The lack of a significant relationship between FoxP2 expression and individual variability in vocal learning performance suggests that other neurogenetic mechanisms could also regulate this complex behavior.

Species worldwide are experiencing anthropogenic environmental change, and the long-term impacts on animal cultural traditions such as vocal dialects are often unknown. Our prior studies of the yellow-naped amazon (Amazona auropalliata) revealed stable vocal dialects over an 11-year period (1994-2005), with modest shifts in geographic boundaries and acoustic structure of contact calls. Here, we examined whether yellow-naped amazons maintained stable dialects over the subsequent 11-year time span from 2005 to 2016, culminating in 22 years of study. Over this same period, this species suffered a dramatic decrease in population size that prompted two successive uplists in IUCN status, from vulnerable to critically endangered. In this most recent 11-year time span, we found evidence of geographic shifts in call types, manifesting in more bilingual sites and introgression across the formerly distinct North-South acoustic boundary. We also found greater evidence of acoustic drift, in the form of new emerging call types and greater acoustic variation overall. These results suggest cultural traditions such as dialects may change in response to demographic and environmental conditions, with broad implications for threatened species.

Animals can actively encode different types of identity information in learned communication signals, such as group membership or individual identity. The social environments in which animals interact may favor different types of information, but whether identity information conveyed in learned signals is robust or responsive to social disruption over short evolutionary timescales is not well understood. We inferred the type of identity information that was most salient in vocal signals by combining computational tools, including supervised machine learning, with a conceptual framework of "hierarchical mapping", or patterns of relative acoustic convergence across social scales. We used populations of a vocal learning species as a natural experiment to test whether the type of identity information emphasized in learned vocalizations changed in populations that experienced the social disruption of introduction into new parts of the world. We compared the social scales with the most salient identity information among native and introduced range monk parakeet (Myiopsitta monachus) calls recorded in Uruguay and the United States, respectively. We also evaluated whether the identity information emphasized in introduced range calls changed over time. To place our findings in an evolutionary context, we compared our results with another parrot species that exhibits well-established and distinctive regional vocal dialects that are consistent with signaling group identity. We found that both native and introduced range monk parakeet calls displayed the strongest convergence at the individual scale and minimal convergence within sites. We did not identify changes in the strength of acoustic convergence within sites over time in the introduced range calls. These results indicate that the individual identity information in learned vocalizations did not change over short evolutionary timescales in populations that experienced the social disruption of introduction. Our findings point to exciting new research directions about the robustness or responsiveness of communication systems over different evolutionary timescales.

Introduction Vocal dialects are a taxonomically widespread phenomenon which are typically only studied in a portion of a species’ range. Thus, it is difficult to infer whether a geographic pattern of vocal dialects observed in one part of a species’ range are typical across the range or whether local conditions influence their presence or absence. We examined the yellow-naped amazon, Amazona auropalliata , a parrot species with remarkable vocal learning capabilities. Although this species’ native range spans across Mesoamerica, only Costa Rican populations have been evaluated long-term. Previous studies have shown that these populations have geographically and temporally stable vocal dialect patterns. Without data on populations outside of Costa Rica, it is impossible to know whether vocal dialects are present in northern range populations, and whether they show similar geographic structure to southern range populations. Introduction We recorded yellow-naped amazon contact calls at 47 different sites across the species’ range between 2016 and 2019 and evaluated them for the presence of dialects. We visually classified 14 contact call types based on spectrographic similarity and used spectrographic cross-correlation, principal component analysis, and Mantel-based spatial autocorrelations to assess acoustic similarity; we also evaluated the robustness of our findings using simulated data. Results and Discussion The results from our study show that the vocal patterns previously seen in Costa Rica are also present in northern populations, supporting our hypothesis that this species has vocal dialects throughout its Mesoamerican range. Call types were regionally specific (e.g., vocal dialects occurred) across the range, and no call types were repeated across multiple regions. We did, however, observe distinctive structural characteristics that are found in multiple call types, suggesting that different call types stem from a common origin. Alternatively, similarity in the acoustic features of call types may also be a result of physiological and anatomical features that are common to all members of the species. Vocal dialects in this species are likely maintained through a tendency toward philopatry and matching call types to enhance social identification.

In some species, the ability to acquire new vocalizations persists into adulthood and may be an important mediator of social interactions. While it is generally assumed that vocal learning persists undiminished throughout the lifespan of these open-ended learners, the stability of this trait remains largely unexplored. We hypothesize that vocal learning exhibits senescence, as is typical of complex cognitive traits, and that this decline relates to age-dependent changes in social behaviour. The budgerigar ( Melopsittacus undulatus ), an open-ended learner that develops new contact call types that are shared with social associates upon joining new flocks, provides a robust assay for measuring the effects of ageing on vocal learning ability. We formed captive flocks of 4 previously unfamiliar adult males of the same age class, either ‘young adults’ (6 mo−1 y) or ‘older adults’ (≥ 3 y), and concurrently tracked changes in contact call structure and social interactions over time. Older adults exhibited decreased vocal diversity, which may be related to sparser and weaker affiliative bonds observed in older adults. Older adults, however, displayed equivalent levels of vocal plasticity and vocal convergence compared to young adults, suggesting that many components of vocal learning are largely maintained into later adulthood in an open-ended learner.

Gene tree discordance is expected in phylogenomic trees and biological processes are often invoked to explain it. However, heterogeneous levels of phylogenetic signal among individuals within data sets may cause artifactual sources of topological discordance. We examined how the information content in tips and subclades impacts topological discordance in the parrots (Order: Psittaciformes), a diverse and highly threatened clade of nearly 400 species. Using ultraconserved elements from 96% of the clade's species-level diversity, we estimated concatenated and species trees for 382 ingroup taxa. We found that discordance among tree topologies was most common at nodes dating between the late Miocene and Pliocene, and often at the taxonomic level of the genus. Accordingly, we used two metrics to characterize information content in tips and assess the degree to which conflict between trees was being driven by lower-quality samples. Most instances of topological conflict and nonmonophyletic genera in the species tree could be objectively identified using these metrics. For subclades still discordant after tip-based filtering, we used a machine learning approach to determine whether phylogenetic signal or noise was the more important predictor of metrics supporting the alternative topologies. We found that when signal favored one of the topologies, the noise was the most important variable in poorly performing models that favored the alternative topology. In sum, we show that artifactual sources of gene tree discordance, which are likely a common phenomenon in many data sets, can be distinguished from biological sources by quantifying the information content in each tip and modeling which factors support each topology. [Historical DNA; machine learning; museomics; Psittaciformes; species tree.].

Previous studies have demonstrated a correlation between longevity and brain size in a variety of taxa. Little research has been devoted to understanding this link in parrots; yet parrots are well-known for both their exceptionally long lives and cognitive complexity. We employed a large-scale comparative analysis that investigated the influence of brain size and life-history variables on longevity in parrots. Specifically, we addressed two hypotheses for evolutionary drivers of longevity: the cognitive buffer hypothesis , which proposes that increased cognitive abilities enable longer lifespans, and the expensive brain hypothesis , which holds that increases in lifespan are caused by prolonged developmental time of, and increased parental investment in, large-brained offspring . We estimated life expectancy from detailed zoo records for 133 818 individuals across 244 parrot species. Using a principled Bayesian approach that addresses data uncertainty and imputation of missing values, we found a consistent correlation between relative brain size and life expectancy in parrots. This correlation was best explained by a direct effect of relative brain size. Notably, we found no effects of developmental time, clutch size or age at first reproduction. Our results suggest that selection for enhanced cognitive abilities in parrots has in turn promoted longer lifespans.

Synopsis Global environmental changes induced by human activities are forcing organisms to respond at an unprecedented pace. At present we have only a limited understanding of why some species possess the capacity to respond to these changes while others do not. We introduce the concept of multidimensional phenospace as an organizing construct to understanding organismal evolutionary responses to environmental change. We then describe five barriers that currently challenge our ability to understand these responses: (1) Understanding the parameters of environmental change and their fitness effects, (2) Mapping and integrating phenotypic and genotypic variation, (3) Understanding whether changes in phenospace are heritable, (4) Predicting consistency of genotype to phenotype patterns across space and time, and (5) Determining which traits should be prioritized to understand organismal response to environmental change. For each we suggest one or more solutions that would help us surmount the barrier and improve our ability to predict, and eventually manipulate, organismal capacity to respond to anthropogenic change. Additionally, we provide examples of target species that could be useful to examine interactions between phenotypic plasticity and adaptive evolution in changing phenospace.