Do standard behavioral assays predict foraging behavior of individual Black-capped chickadees (Poecile atricapillus) in response to a predator model or calls?

Black-capped chickadees (Poecile atricapillus) and other species that feed at bird feeders balance the benefit of easy foraging with the added risk of predation. Individual birds respond differently to risky situations, and these differences have been attributed to the birds' personalities, which researchers commonly assess with an "open-field" behavioral assay. However, these behavioral assays in birds have not been compared to behavior in the wild in the context of foraging in the presence of a predator (i.e., risk-taking behavior). We color-banded chickadees in a wild population and conducted behavioral assays in the field. We later used foraging trials to investigate these color-banded individuals' responses to a predator (Cooper's hawk, Accipiter cooperii) model or a series of Cooper's hawk calls. We found that foraging black-capped chickadees responded more strongly to the presence of a predator model than to predator calls. Individual birds differed in their responses, and the behavioral assays (activity and exploration) predicted individual behavior in the wild during the foraging experiments. Activity and exploration assay scores were only weakly related, suggesting these two assays represent different traits. Both highly active birds and fast explorers exhibited some reluctance to visit the feeder (either reduced number of visits or greater latency to visit) when the predator model was present, a relationship that was somewhat unexpected. Our results suggest that standard behavioral assays predict behavior in the wild, but care should be taken when generalizing among species and studies. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Individual variation in Black-capped chickadee (Poecile atricapillus) foraging behavior in response to a predator model.

Birds that forage at feeders must balance the risk of predation with the benefit of food acquisition. We color-banded black-capped chickadees (Poecile atricapillus) in a wild population and investigated their responses to a predator (Cooper's hawk, Accipiter cooperii) model placed 1 m or 5 m from a feeding platform. Over 40 trials, we recorded a total of 3,576 chickadee visits to a feeder. When the predator model was present, chickadees made fewer and shorter visits to the feeder, and there was greater latency to visit the feeder than during all other phases of the trials (prestimulus, poststimulus, and with the presence of a control model, a songbird [all p < .05]). Individual birds were highly consistent in the number of visits across phases (adjusted intraclass correlation coefficient = .958). Nonmetric multidimensional scaling allowed visualization of differences among individuals in the number of visits by trial phase. Although all 16 color-banded birds made fewer visits to the feeder when the predator model was present, some individuals were bolder than others, and some were more cautious. In addition, 4 individuals (25%) also made fewer visits when the songbird model was present, 3 different individuals (19%) also made fewer visits during the postpredator phase, and 1 (6.3%) individual was cautious about both the songbird and during the postpredator phase. Distance-based redundancy analysis (dbRDA) indicated that individuals' latency among phases explained significant variation in their number of visits. Examining behavioral responses on an individual basis allowed a more subtle understanding of behavior along the boldness-shyness continuum. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Patterns and Trends of Polybrominated Diphenyl Ethers in Bald Eagle Nestlings in Minnesota and Wisconsin, USA.

We measured concentrations of up to 17 polybrominated diphenyl ethers (PBDEs) in plasma of 492 bald eagle (Haliaeetus leucocephalus) nestlings between 1995 and 2017 from 12 study areas in Wisconsin and Minnesota, USA. Geometric mean concentrations of the sum of 9 PBDE congeners (∑PBDE) measured across all years ranged from 2.88 to 10.8 µg/L, and nestlings in urban areas had higher concentrations than those in remote locations. Region-wide from 2006 through 2017, we found that ∑PBDEs declined by 3.8% annually and congeners BDE-47, -99, and -100 declined by 5.6 to 6.5%, whereas BDE-153 and -154 had no significant declines. When categorized by waterbody type, nestlings from Great Lakes and river study areas had higher concentrations of ∑PBDEs than those at inland lakes, but river study areas spanned the extremes. From 2006 to 2017, ∑PBDEs declined by 7.3% annually in Great Lakes nestlings and by 3.2% in nestlings along rivers, and increased by 32.7% at inland lakes. Using a longer dataset (1995-2015), we found that ∑PBDEs declined in Lake Superior nestlings by 3.3% annually. Our results show that PBDEs declined in bald eagle nestling plasma in most study areas since PBDE production was reduced, but that concentrations remain high near urban centers and that trends differ by congener, study area, and waterbody type. Environ Toxicol Chem 2021;40:1606-1618. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Trends and Patterns of Perfluoroalkyl Substances in Blood Plasma Samples of Bald Eagle Nestlings in Wisconsin and Minnesota, USA.

We analyzed concentrations and trends of perfluoroalkyl substances (PFAS) in blood plasma samples of bald eagle (Haliaeetus leucocephalus) nestlings at 6 study areas in the upper Midwest of the United States, 2006 to 2015, and long-term trends at 2 Lake Superior (USA/Canada) sites, 1995 to 2015. Nestling blood plasma concentrations of the sum of 15 PFAS analytes (∑PFAS) differed among study areas and were highest at the 3 industrialized river sites: pools 3 and 4 of the Mississippi River (pools 3 + 4; geometric mean [GM] = 754 µg/L; range = 633-2930), the Mississippi National River and Recreation Area (GM = 687 µg/L; range = 24-7371), and the lower St. Croix National Scenic Riverway (GM = 546 µg/L; range = 20-2400). Temporal trends in ∑PFAS in nestling plasma differed among study areas; concentrations decreased at pools 3 + 4, Mississippi National River and Recreation Area, and lower St. Croix National Scenic Riverway, but not at the most remote sites, the upper St. Croix River and Lake Superior. Overall, perfluorooctanesulfonate (PFOS) was the most abundant analyte at all study areas, and perfluorodecanesulfonate (PFDS) the second most abundant at industrialized river sites although not at Lake Superior; concentrations of both these analytes declined from 2006 to 2015 over the study area. In addition, nestling age significantly influenced plasma concentrations of ∑PFAS and 7 of the 12 analytes. For these analytes, concentrations increased by 1 to 2%/d as nestlings grew, indicating that age should be considered when using nestling plasma to assess PFAS. Environ Toxicol Chem 2021;40:754-766. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Raptor research during the COVID-19 pandemic provides invaluable opportunities for conservation biology.

Research is underway to examine how a wide range of animal species have responded to reduced levels of human activity during the COVID-19 pandemic. In this perspective article, we argue that raptors (i.e., the orders Accipitriformes, Cariamiformes, Cathartiformes, Falconiformes, and Strigiformes) are particularly well-suited for investigating potential 'anthropause' effects: they are sensitive to environmental perturbation, affected by various human activities, and include many locally and globally threatened species. Lockdowns likely alter extrinsic factors that normally limit raptor populations. These environmental changes are in turn expected to influence - mediated by behavioral and physiological responses - the intrinsic (demographic) factors that ultimately determine raptor population levels and distributions. Using this population-limitation framework, we identify a range of research opportunities and conservation challenges that have arisen during the pandemic, related to changes in human disturbance, light and noise pollution, collision risk, road-kill availability, supplementary feeding, and persecution levels. Importantly, raptors attract intense research interest, with many professional and amateur researchers running long-term monitoring programs, often incorporating community-science components, advanced tracking technology and field-methodological approaches that allow flexible timing, enabling continued data collection before, during, and after COVID-19 lockdowns. To facilitate and coordinate global collaboration, we are hereby launching the 'Global Anthropause Raptor Research Network' (GARRN). We invite the international raptor research community to join this inclusive and diverse group, to tackle ambitious analyses across geographic regions, ecosystems, species, and gradients of lockdown perturbation. Under the most tragic of circumstances, the COVID-19 anthropause has afforded an invaluable opportunity to significantly boost global raptor conservation.

Patterns and trends in brominated flame retardants in bald eagle nestlings from the upper midwestern United States.

We report on patterns and trends in polybrominated diphenyl ethers (PBDEs) in the plasma of 284 bald eagle nestlings sampled between 1995 and 2011 at six study areas in the upper Midwestern United States. Geometric mean concentrations of total PBDEs (Σ of nine congeners) ranged from 1.78 ng/mL in the upper St. Croix River watershed to 12.0 ng/mL on the Mississippi River. Lake Superior nestlings fell between these two extremes. Between 2006 and 2011, trends differed among study areas with three declining, two remaining stable, and one increasing. Variation in ΣPBDE trends among study areas was linked to trends in individual congeners. The lower brominated PBDEs (BDE-47, -99, and -100) declined 4-10% while the higher brominated congeners (BDE-153 and -154) increased by about 7.0% annually from 2006 to 2011. This increase was the greatest in nestlings from the St. Croix River and below its confluence with the Mississippi River. Region-wide, our data suggest ΣPBDEs increased in bald eagle nestlings from 1995 through the mid-2000s and then declined by 5.5% annually from 2006 to 2011. These regional trends are consistent with the removal of penta- and octa-PBDEs from the global market.

Comparative phylogeography and population genetics within Buteo lineatus reveals evidence of distinct evolutionary lineages.

Traditional subspecies classifications may suggest phylogenetic relationships that are discordant with evolutionary history and mislead evolutionary inference. To more accurately describe evolutionary relationships and inform conservation efforts, we investigated the genetic relationships and demographic histories of Buteo lineatus subspecies in eastern and western North America using 21 nuclear microsatellite loci and 375-base pairs of mitochondrial control region sequence. Frequency based analyses of mitochondrial sequence data support significant population distinction between eastern (B. l. lineatus/alleni/texanus) and western (B. l.elegans) subspecies of B. lineatus. This distinction was further supported by frequency and Bayesian analyses of the microsatellite data. We found evidence of differing demographic histories between regions; among eastern sites, mitochondrial data suggested that rapid population expansion occurred following the end of the last glacial maximum, with B. l. texanus population expansion preceding that of B. l. lineatus/alleni. No evidence of post-glacial population expansion was detected among western samples (B. l.elegans). Rather, microsatellite data suggest that the western population has experienced a recent bottleneck, presumably associated with extensive anthropogenic habitat loss during the 19th and 20th centuries. Our data indicate that eastern and western populations of B. lineatus are genetically distinct lineages, have experienced very different demographic histories, and suggest management as separate conservation units may be warranted.