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Daily torpor allows endotherms to save energy during energetically stressful (e.g. cold) conditions. Although studies on avian torpor have mostly been conducted under laboratory conditions, information on the usage of torpor in the wild is limited to few, predominantly temperate-zone species. We studied torpor under seminatural conditions from 249 individuals from 29 hummingbird species across a 1920 m elevational gradient in the western Andes of Colombia using cloacal thermistors. Small birds were more likely to use torpor than large birds, but only at low ambient temperatures, where torpor was prolonged. We also found effects of proxy variables for body condition and energy expenditure on the use of torpor, its characteristics, and impacts. Our results suggest that context-dependency and phylogenetic variation in the probability of deploying torpor can help understand clade-wide patterns of elevational distribution in Andean hummingbirds. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change is rapidly altering local environments and threatening biodiversity throughout the world. Although many wildlife responses to this phenomenon appear largely idiosyncratic, a wealth of basic research on this topic is enabling the identification of general patterns across taxa. Here, we expand those efforts by investigating how avian responses to climate change are affected by the ability to cope with ecological variation through behavioural flexibility (as measured by relative brain size). After accounting for the effects of phylogenetic uncertainty and interspecific variation in adaptive potential, we confirm that although climate warming is generally correlated with major body size reductions in North American migrants, these responses are significantly weaker in species with larger relative brain sizes. Our findings suggest that cognition can play an important role in organismal responses to global change by actively buffering individuals from the environmental effects of warming temperatures. [ABSTRACT FROM AUTHOR]

Highlights • State-space models for Motus data from migratory birds. • Simple localization routine predicts bird location and spatial uncertainty. • New movement models for migratory birds flying at night. • Estimate unobserved locations and behaviors (e.g. migration and foraging). • Red-eyed Vireos performed most migratory flights at night and over water. Abstract Recent advances in wildlife tracking technology, including the Motus system, have allowed researchers to continuously track small organisms with lightweight radio transmitters over large spatial and temporal ranges. The quantity and format of data generated by the Motus system is unprecedented and requires novel statistical methods. Building from the bsam package in R, we propose new biologically informed Bayesian state-space models for animal movement in JAGS that include informed assumptions about behavior. To apply the models, we employed a localization routine on a Motus data set from migrating Red-eyed Vireos (Vireo olivaceus). This allowed us to apply the new models to estimate unobserved locations and behaviors. Directed migratory flights were detected at night and often over water (e.g. the Bay of Fundy, the Long Island Sound and the New York Bight). Migratory flights were not exclusively nocturnal. [ABSTRACT FROM AUTHOR]

We present the first detailed nesting biology information for the highland Andean hummingbird Gould's Inca ( Coeligena torquata omissa) at 2,200-3,000 m in Manu National Park, SE Peru. We found nine mossy cup-shaped nests lined with red fern scales containing nestlings or 1-2 synchronously hatching eggs. We obtained 17 days of internal nest temperatures from one nest, which exhibited wide circadian variation (range = 14.9-36.2 °C). We show that C. t. omissa meets the challenges of life and incubation at high altitudes by undertaking numerous (20.3 ± 0.4 trips/morning, range = 14-27) and short morning off-bouts (5.2 ± 0.2 min, range = 1-24 min). In the morning, the focal bird warmed the nest 1.7 times faster than in the afternoon where incubation bouts are long (17.8 ± 0.6 min, range = 4-56) and less frequent (10.2 ± 0.3 trips/afternoon). Incubation off-bout frequency and durations were not influenced by external temperature, suggesting strong nest insulation. On-bout durations increased with external temperature most strongly in the cold mornings. Short off-bouts and long on-bouts yielded high attentiveness (70.2%). One nestling fledged after 23 days. The eggs measured 15.2 ± 0.4 mm by 9.3 ± 0.3 mm and weighed 0.75 ± 0.03 g ( n = 12). The small mossy cup nest was 81.9 ± 5.9 mm by 75.8 ± 4.4 mm wide and 73.1 ± 6.7 mm high. The inner cup was 45.7 ± 3.0 mm long by 45.6 ± 4.1 mm wide and 30.9 ± 2.5 mm deep ( n = 8). Compared to C. t. torquata, we found a smaller egg width, higher nest placement and different nest substrate, but confirmed similarities in many aspects of nesting strategies. [ABSTRACT FROM AUTHOR]

The paradoxical presence of toxic chemical compounds in ripe fruits represents a balance between plant enemies and allies: chemical traits can defend seeds against antagonistic herbivores, seed predators, or fungal pathogens, but also can impose costs by repelling mutualistic seed dispersers, although the costs are often difficult to quantify. Seeds gain fitness benefits from traveling far from the parent plant, as they can escape from parental competition and elude specialized herbivores as well as pathogens that accumulate on adult plants. However, seeds are difficult to follow from their parent plant to their final destination. Thus, little is known about the factors that determine seed dispersal distance. We investigated this potential cost of fruit secondary compounds, reduced seed dispersal distance, by combining two data sets from previous work on a Neotropical bat‐plant dispersal system (bats in the genus Carollia and plants in the genus Piper). We used data from captive behavioral experiments, which show how amides in ripe fruits of Piper decrease the retention time of seeds and alter food choices. With new analyses, we show that these defensive secondary compounds also delay the time of fruit removal. Next, with a behaviorally annotated bat telemetry data set, we quantified post‐feeding movements (i.e., seed dispersal distances). Using generalized additive mixed models we found that seed dispersal distances varied nonlinearly with gut retention times as well as with the time of fruit removal. By interrogating the model predictions, we identified two novel mechanisms by which fruit secondary compounds can impose costs in terms of decreased seed dispersal distances: (1) small‐scale reductions in gut retention time and (2) causing fruits to forgo advantageous bat activity peaks that confer high seed dispersal distances. [ABSTRACT FROM AUTHOR]

Background: Was there a mid-Cenozoic vertebrate extinction and recovery event in Madagascar and, if so, what are its implications for the evolution of lemurs? The near lack of an early and mid-Cenozoic fossil record on Madagascar has inhibited direct testing of any such hypotheses. We compare the terrestrial vertebrate fauna of Madagascar in the Holocene to that of early Cenozoic continental Africa to shed light on the probability of a major mid-Cenozoic lemur extinction event, followed by an "adaptive radiation" or recovery. We also use multiple analytic approaches to test competing models of lemur diversification and the null hypothesis that no unusual mid-Cenozoic extinction of lemurs occurred. Results: Comparisons of the terrestrial vertebrate faunas of the early Cenozoic on continental Africa and Holocene on Madagascar support the inference that Madagascar suffered a major mid-Cenozoic extinction event. Evolutionary modeling offers some corroboration, although the level of support varies by phylogeny and model used. Using the lemur phylogeny and divergence dates generated by Kistler and colleagues, RPANDA and TESS offer moderate support for the occurrence of unusual extinction at or near the Eocene-Oligocene (E-O) boundary (34 Ma). TreePar, operating under the condition of obligate mass extinction, found peak diversification at 31 Ma, and low probability of survival of prior lineages. Extinction at the E-O boundary received greater support than other candidate extinctions or the null hypothesis of no major extinction. Using the lemur phylogeny and divergence dates generated by Herrera & Dàvalos, evidence for large-scale extinction diminishes and its most likely timing shifts to before 40 Ma, which fails to conform to global expectations. Conclusions: While support for large-scale mid-Cenozoic lemur extinction on Madagascar based on phylogenetic modeling is inconclusive, the African fossil record does provide indirect support. Furthermore, a major extinction and recovery of lemuriforms during the Eocene-Oligocene transition (EOT) would coincide with other major vertebrate extinctions in North America, Europe, and Africa. It would suggest that Madagascar's lemurs were impacted by the climate shift from "greenhouse" to "ice-house" conditions that occurred at that time. This could, in turn, help to explain some of the peculiar characteristics of the lemuriform clade. [ABSTRACT FROM AUTHOR]

Rationale: In utero opioid exposure is associated with lower weight and a neonatal opioid withdrawal syndrome (NOWS) at birth, along with longer-term adverse neurodevelopmental outcomes and mood disorders. While NOWS is sometimes treated with continued opioids, clinical studies have not addressed if long-term neurobehavioral outcomes are worsened with continued postnatal exposure to opioids. In addition, pre-clinical studies comparing in utero only opioid exposure to continued post-natal opioid administration for withdrawal mitigation are lacking. Objectives: Here, we sought to understand the impact of continued postnatal opioid exposure on long term behavioral consequences. Methods: We implemented a rodent perinatal opioid exposure model of oxycodone (Oxy) exposure that included Oxy exposure until birth (short Oxy) and continued postnatal opioid exposure (long Oxy) spanning gestation through birth and lactation. Results: Short Oxy exposure was associated with a sex-specific increase in weight gain trajectory in adult male mice. Long Oxy exposure caused an increased weight gain trajectory in adult males and alterations in nociceptive processing in females. Importantly, there was no evidence of long-term social behavioral deficits, anxiety, hyperactivity, or memory deficits following short or long Oxy exposure. Conclusions: Our findings suggest that offspring with prolonged opioid exposure experienced some long-term sequelae compared to pups with opioid cessation at birth. These results highlight the potential long-term consequences of opioid administration as a mitigation strategy for clinical NOWS symptomology and suggest alternatives should be explored. [ABSTRACT FROM AUTHOR]

Within the large order of bats, sexual size dimorphism measured by forearm length and body mass is often female-biased. Several studies have explained this through the effects on load carrying during pregnancy, intrasexual competition, as well as the fecundity and thermoregulation advantages of increased female body size. We hypothesized that wing shape should differ along with size and be under variable selection pressure in a species where there are large differences in flight behaviour. We tested whether load carrying, sex differential migration, or reproductive advantages of large females affect size and wing shape dimorphism in the common noctule (Nyctalus noctula), in which females are typically larger than males and only females migrate long distances each year. We tested for univariate and multivariate size and shape dimorphism using data sets derived from wing photos and biometric data collected during pre-migratory spring captures in Switzerland. Females had forearms that are on average 1% longer than males and are 1% heavier than males after emerging from hibernation, but we found no sex differences in other size, shape, or other functional characters in any wing parameters during this pre-migratory period. Female-biased size dimorphism without wing shape differences indicates that reproductive advantages of big mothers are most likely responsible for sexual dimorphism in this species, not load compensation or shape differences favouring aerodynamic efficiency during pregnancy or migration. Despite large behavioural and ecological sex differences, morphology associated with a specialized feeding niche may limit potential dimorphism in narrow-winged bats such as common noctules and the dramatic differences in migratory behaviour may then be accomplished through plasticity in wing kinematics. [ABSTRACT FROM AUTHOR]