Condor最新文献

{"title":"Piping Plover population increase after Hurricane Sandy mediated by immigration and reproductive output","authors":"Samantha G. Robinson, D. Gibson, Thomas V. Riecke, J. Fraser, Henrietta A. Bellman, Audrey Derose‐Wilson, S. Karpanty, Katie M. Walker, D. Catlin","doi":"10.1093/condor/duaa041","DOIUrl":"https://doi.org/10.1093/condor/duaa041","url":null,"abstract":"ABSTRACT Evaluating population-level responses to conservation action following large-scale disturbance can improve the efficacy of future habitat conservation measures. In October 2012, Hurricane Sandy storm surges cleared vegetation and opened inlets through the barrier islands, Fire Island and Westhampton Island, New York, creating Piping Plover (Charadrius melodus) habitat. Storm effects prompted an island-wide stabilization project, which had the potential to negatively affect novel Piping Plover habitat. Certain sections of Fire Island were designed to create and/or improve habitat (hereafter, restoration areas) to mitigate possible habitat loss or degradation. Since Piping Plovers in New York appear to be habitat-limited, we anticipated positive population growth following habitat creation. From 2013 to 2018, we captured and banded 152 adults and 353 chicks, and monitored 279 nests and 160 broods. We developed an integrated population model to assess demographic processes in response to hurricane created-habitat (2013–2018) and the creation of restoration areas (2015–2018). We observed positive population growth in 3 of 5 yr, and overall growth throughout the period ( = 1.13). Immigration and reproductive output were correlated with population growth (r = 0.92 [95% CI: 0.22 to 0.98] and 0.84 [95% CI: –0.47 to 0.95], respectively). Compared with the rest of the study area, restoration areas had higher chick survival, and lower nest survival and after second-year site fidelity. The result was population growth in restoration areas ( = 1.14) similar to the whole study area. In the short term, restoration areas seemed to mimic natural Piping Plover habitat. Vegetation removal, an important process in renewing natural Piping Plover habitat, likely will be necessary to maintain habitat suitability. Efforts to increase immigration of new breeding adults into the system, and to improve reproductive output, primarily by habitat creation or maintenance, are likely to have the greatest local effect on population growth. LAY SUMMARY Despite being listed under the Endangered Species Act for more than 30 yr, and intensive management, Piping Plovers on the Atlantic Coast have not met population recovery goals across much of their breeding range. Hurricane Sandy increased available nesting habitat (dry sand) by over 150%. Following Hurricane Sandy, we monitored a population of individually marked birds on Fire Island and West Hampton Island, New York, for 6 yr. The area monitored included restored habitat, to evaluate the effectiveness of Piping Plover targeted habitat management. The population increased 90% in the 6 yr following Hurricane Sandy, primarily because of immigrant adults, and local reproductive success. The reproductive output and population growth in restoration areas were similar to the rest of the study area. Overall, Hurricane Sandy habitat creation was positive for this local plover population. Efforts to allow future hurricane storm su","PeriodicalId":50624,"journal":{"name":"Condor","volume":"122 1","pages":"1 - 20"},"PeriodicalIF":2.4,"publicationDate":"2020-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43005854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protected by dragons: Density surface modeling confirms large population of the critically endangered Yellow-crested Cockatoo on Komodo Island","authors":"A. Reuleaux, B. Siregar, N. Collar, M. R. Panggur, A. Mardiastuti, Martin J. Jones, S. Marsden","doi":"10.1093/condor/duaa042","DOIUrl":"https://doi.org/10.1093/condor/duaa042","url":null,"abstract":"ABSTRACT Intense trapping of the critically endangered Yellow-crested Cockatoo (Cacatua sulphurea) for the international pet trade has devastated its populations across Indonesia such that populations of >100 individuals remain at only a handful of sites. We combined distance sampling with density surface modeling (DSM) to predict local densities and estimate total population size for one of these areas, Komodo Island, part of Komodo National Park (KNP) in Indonesia. We modeled local density based on topography (topographic wetness index) and habitat types (percentage of palm savanna and deciduous monsoon forest). Our population estimate of 1,113 (95% CI: 587–2,109) individuals on Komodo Island was considerably larger than previous conservative estimates. Our density surface maps showed cockatoos to be absent over much of the island, but present at high densities in wooded valleys. Coincidence between our DSM and a set of independent cockatoo observations was high (93%). Standardized annual counts by KNP staff in selected areas of the island showed increases in cockatoo records from <400 in 2011 to ∼650 in 2017. Taken together, our results indicate that KNP, alongside and indeed because of preserving its iconic Komodo dragons (Varanus komodoensis), is succeeding in protecting a significant population of Indonesia's rarest cockatoo species. To our knowledge this is the first time DSM has been applied to a critically endangered species. Our findings highlight the potential of DSM for locating abundance hotspots, identifying habitat associations, and estimating global population size in a range of threatened taxa, especially if independent datasets can be used to validate model predictions. LAY SUMMARY Yellow-crested Cockatoos are threatened by extinction due to illegal trapping for the pet trade. Komodo Island in Indonesia supports one of the largest remaining populations. The island is part of Komodo National Park, famous for its Komodo dragons. A 2006 survey indicated cockatoo numbers might have been declining. In contrast to previous surveys we sampled the whole island instead of focusing on coastal valleys, which are known to harbor the highest cockatoo densities. We used distance sampling and density surface modeling, which allowed us to estimate how many cockatoos remained undetected and to produce a map of predicted cockatoo densities. We estimate there are between 600 and 2,100 cockatoos on Komodo, most likely ∼1,100. Komodo National Park authorities also reported an increase in their annual counts of cockatoos from below 400 in 2011 to around 650 in 2017. Thus, the cockatoo population on Komodo Island is large and stable; Komodo National Park is successfully protecting its cockatoos.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 15"},"PeriodicalIF":2.4,"publicationDate":"2020-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43288458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A parasite reduction conservation intervention does not improve fledging success or most condition metrics for Purple Martins","authors":"Heather M. Williams, K. Dittmar, S. S. Pagano","doi":"10.1093/condor/duaa051","DOIUrl":"https://doi.org/10.1093/condor/duaa051","url":null,"abstract":"ABSTRACT Eastern Purple Martins (Progne subis subis) have an unusually close relationship with humans, as they nest exclusively in man-made nest boxes. Current conservation policy directly promotes further interaction with this species by advocating regular replacement of nest materials during the nestling phase to reduce ectoparasite load and increase nestling fitness. We conducted the first test of the efficacy of this recommendation and found that it was partially effective in reducing parasite abundance, but had no effect on nestling fledging success, body mass, leukocyte count, or triglyceride or uric acid concentration. We found a small but significant increase in nestling hematocrit associated with nest material replacement, implying that parasites may induce nestling anemia. Contrary to our expectations, we also found elevated heterophil/lymphocyte ratios in nestlings with replacements, possibly indicating elevated physiological stress associated with nest replacements. Based on our results, we do not recommend nest material replacements to combat routine parasite infestations. LAY SUMMARY Purple Martins are believed to have a high abundance of blood-feeding parasites (fleas, mites, and blowfly larvae) in their nests. A current conservation policy recommends that nest box managers regularly remove and replace nest materials during the nestling phase to reduce parasite abundance. We tested the efficacy of this policy. Nest replacements reduced flea and blowfly larvae abundance, but mite abundance rebounded quickly. There was no difference in fledging rate, body mass, white blood cell count, or triglyceride or uric acid levels for nestlings with or without nest replacements. Nestlings with nest replacements were less anemic and had a higher ratio of heterophils to lymphocytes.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 14"},"PeriodicalIF":2.4,"publicationDate":"2020-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43905026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Agricultural land in the Amazon basin supports low bird diversity and is a poor replacement for primary forest","authors":"M. H. Neate‐Clegg, Ç. Şekercioğlu","doi":"10.1093/condor/duaa020","DOIUrl":"https://doi.org/10.1093/condor/duaa020","url":null,"abstract":"ABSTRACT The Amazon has a long history of disturbance under subsistence agriculture, but slash-and-burn agriculture is small in scale and has relatively low impact on resident avifauna. More recently, the Amazon has suffered extensive deforestation in favor of cattle ranching and other modern systems of agriculture. Cattle pastures, mechanized agriculture, and even tree plantations have detrimental effects on bird communities, greatly lowering diversity, especially that of primary forest interior specialists. A rising threat to the Amazon is the spread of oil palm plantations that retain few bird species and are not viable alternatives to forest. Embedded within the expanding agropastoral mosaic are forest fragments that have experienced a well-documented loss of diversity. Yet, the matrix can mitigate the recovery of fragmented bird communities depending on the type of secondary regrowth. Connectivity via matrix habitats or forest corridors is critical for the maintenance of forest avifauna. With so many types of land use developing across the Amazon, the “tropical countryside” has potential value for bird diversity. However, evidence suggests that the agropastoral mosaic harbors a small, more homogenized avifauna with few forest species, especially when primary forest is absent from the landscape. For the Amazon Basin's bird life to be conserved into the future, preservation of large tracts of well-connected primary forest is vital. Tropical countryside dominated by agriculture simply cannot sustain sufficient levels of biodiversity.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 11"},"PeriodicalIF":2.4,"publicationDate":"2020-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49213961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in Neotropical Ornithology: A Special Feature","authors":"C. Lindell, K. Huyvaert","doi":"10.1093/condor/duaa049","DOIUrl":"https://doi.org/10.1093/condor/duaa049","url":null,"abstract":"1 Integrative Biology Department, Michigan State University, East Lansing, Michigan, USA 2 Center for Global Change and Earth Observations, Michigan State University, East Lansing, Michigan, USA 3 Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, Michigan, USA 4 Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, USA *Corresponding author: lindellc@msu.edu","PeriodicalId":50624,"journal":{"name":"Condor","volume":"122 1","pages":"1 - 2"},"PeriodicalIF":2.4,"publicationDate":"2020-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41639595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal rainfall in subtropical montane cloud forests drives demographic fluctuations in a Green-backed Tit population","authors":"Ming-Tang Shiao, M. Chuang, Hsiao-Wei Yuan, Ying Wang","doi":"10.1093/condor/duaa043","DOIUrl":"https://doi.org/10.1093/condor/duaa043","url":null,"abstract":"ABSTRACT Montane birds are vulnerable to climate change. However, the mechanisms by which weather drives demographic processes in montane birds have seldom been investigated. We conducted a long-term study (2009–2019) on the Green-backed Tit (Parus monticolus), an insectivorous passerine, in the montane cloud forest of subtropical Taiwan. We explored the effects of weather variability on the productivity and survival of adult Green-backed Tits. Nest survival was negatively associated with seasonal rainfall during the breeding season (April–July) and was lower in early clutches than in late clutches. Higher typhoon-induced precipitation during the postbreeding period (July–September) was related to reduced adult survival, but neither summer temperature nor winter weather conditions were found to be related to adult bird survival. We developed a stochastic simulation model for Green-backed Tit population dynamics based on empirical data. We compared the simulated time-series and observed population growth rates (λ) and found that 80% (8/10 yr) of the observed λ fell within the 5th and 95th percentiles of the simulated data over the 10-yr period. Moreover, the simulated average (± standard deviation) of the geometric mean of λ over 10 yr (1.05 ± 0.07) was close to that observed from 2009 to 2019 (0.99), which provided confidence that the model effectively simulated the population growth rate of the Green-backed Tit. We conducted a sensitivity analysis for λ and found that juvenile and adult survival influenced by typhoon-induced rainfall were the greatest contributors to the variance in the growth rate of the Green-backed Tit population. With the onset of intensified seasonal precipitation associated with global warming, the population growth and density of Green-backed Tits will decline substantially. Our results suggest that under scenarios of high emissions of greenhouse gas, this local population of Green-backed Tits will not persist in the near future. LAY SUMMARY Although montane birds are vulnerable to climate change, the effect of weather on their demography has seldom been investigated. We examined the vital rates of the Green-backed Tit in a subtropical montane forest in Taiwan and constructed a model to simulate their population dynamics. We found seasonal precipitation to be the critical factor driving population fluctuations. High rainfall was related to decreased nest survival; typhoon-induced precipitation was associated with decreased adult survival. As seasonal precipitation is expected to intensify under high greenhouse gas emission scenarios, this local population is unlikely to persist in the future. Hence, the species may become a conservation concern.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 15"},"PeriodicalIF":2.4,"publicationDate":"2020-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48304069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tree Swallow selection for wetlands in agricultural landscapes predicted by central-place foraging theory","authors":"Andrew S. Elgin, R. Clark, C. Morrissey","doi":"10.1093/condor/duaa039","DOIUrl":"https://doi.org/10.1093/condor/duaa039","url":null,"abstract":"ABSTRACT Millions of wetland basins, embedded in croplands and grasslands, are biodiversity hotspots in North America's Prairie Pothole Region, but prairie wetlands continue to be degraded and drained, primarily for agricultural activities. Aerial insectivorous swallows are known to forage over water, but it is unclear whether swallows exhibit greater selection for wetlands relative to other habitats in croplands and grasslands. Central-place foraging theory suggests that habitat selectivity should increase with traveling distance from a central place, such that foragers compensate for traveling costs by selecting more profitable foraging habitat. Using global positioning system (GPS) tags, we evaluated habitat selection by female Tree Swallows (Tachycineta bicolor) at 4 sites containing wetlands and where terrestrial land cover was dominated by grasslands (grass, herbaceous cover) and/or cultivated cropland. We also used sweep-net transects to assess the abundance and biomass of flying insects in different habitats available to swallows (wetland pond margins, grassy field margins, and representative uplands). As expected for a central-place forager, GPS-tagged swallows selected more for wetland ponds (disproportionate to availability), and appeared to increasingly select for wetlands with increasing distance from their nests. On cropland-dominated sites, insect abundance and biomass tended to be higher in pond margins or grassy field margins compared to cropped uplands, while abundance and biomass were more uniform among sampled habitats at sites dominated by grass and herbaceous cover. Swallow habitat selection was not clearly explained by the distribution of sampled insects among habitats; however, traditional terrestrial sampling methods may not adequately reflect prey distribution and availability to aerially foraging swallows. Overall, our results underscore the importance of protecting and enhancing prairie wetlands and other non-crop habitats in agricultural landscapes, given their disproportionate use and capacity to support breeding swallow and insect populations. LAY SUMMARY Miniature GPS tags were used to track breeding female Tree Swallows at agricultural sites. Across agroecosystems, Tree Swallows selected more for wetland ponds than available in the landscape. Swallows increasingly selected for wetland ponds with increasing distance from nests, consistent with central-place foraging theory. Insect abundance and biomass tended to be greater in pond margins and non-crop vegetation (field margins or grasslands) than in croplands, but insect distribution patterns did not fully explain swallow habitat selection.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 12"},"PeriodicalIF":2.4,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42497264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vegetation management on private forestland can increase avian species richness and abundance","authors":"J. Wood, Amy K. Tegeler, Beth E. Ross","doi":"10.1093/condor/duaa048","DOIUrl":"https://doi.org/10.1093/condor/duaa048","url":null,"abstract":"ABSTRACT Conservation efforts on private lands are important for biodiversity conservation. On private lands in South Carolina, in the southeastern United States, forestry management practices (prescribed burning, thinning, herbicide application) are used to improve upland pine habitat for wildlife and timber harvest and are incentivized through U.S. Department of Agriculture Farm Bill cost-share programs. Because many forest-dependent avian species have habitat requirements created primarily through forest management, data are needed on the effectiveness of these management activities. We studied privately owned loblolly pine (Pinus taeda) stands in the South Carolina Piedmont region. Our objective was to understand how management practices influence avian species richness and abundance at local (forest stand) and landscape levels in relatively small stands (average ∼28 ha). We surveyed 49 forest stands during 2 bird breeding seasons with traditional point counts and vegetation surveys. We evaluated the effects of management on pine stand characteristics, avian species richness, and abundance of state-designated bird species of concern. Repeated burning and thinning shifted stand conditions to open pine woodlands with reduced basal area and herbaceous understories. Stands with lower basal area supported greater avian species richness. Some species increased in abundance in response to active management (e.g., Brown-headed Nuthatch [Sitta pusilla] and Indigo Bunting [Passerina cyanea]), but relationships varied. Some species responded positively to increases in forest quantity at a landscape scale (1–5 km; e.g., Northern Bobwhite [Colinus virginianus]). We found species-rich avian communities and species of conservation concern on working timber lands, indicating that incentivized forest management on private lands can provide valuable habitat for wildlife. LAY SUMMARY Private timber lands can provide important habitat for birds, especially when landowners create open forest conditions. We surveyed birds and vegetation in southeastern U.S. loblolly pine forests in 2017 and 2018. Forests managed differently, for example with different numbers of burns, had different structures and compositions and supported different bird totals—both in numbers and types of species. We identified varying factors for different species' abundances from stand basal area to the forest extent (≤5 km).","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 16"},"PeriodicalIF":2.4,"publicationDate":"2020-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45428189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrating vulture social behavior into conservation practice","authors":"Thijs van Overveld, G. Blanco, M. Moléon, A. Margalida, J. A. Sánchez‐Zapata, M. de la Riva, J. Donázar","doi":"10.1093/condor/duaa035","DOIUrl":"https://doi.org/10.1093/condor/duaa035","url":null,"abstract":"ABSTRACT Vultures are one of the most threatened bird groups globally. Although many of the threats faced by vultures have been identified, the impact of human activities on the social life of vultures has received little attention. In this paper, we emphasize the need to integrate vulture sociality into conservation practice. First, we summarize current knowledge on vulture social behavior, and the evolutionary and ecological roots of their breeding systems. We describe the existence of contrasting gradients in social foraging strategies and hierarchical social structures among colonial and territorial breeders associated with species (and population) reliance on carrion differing in size and predictability. We also highlight the potential role of vulture gatherings in maintaining population-level social structures and for mate-finding given high mate-selectivity. Next, based on this social framework, we discuss the impact of human activities on social foraging, territory structures, resource partitioning processes, and mating dynamics. However, little is known about how disruptions of social habits may have contributed to vulture population declines and/or may impede their recovery. Lastly, we provide directions for future research on vulture socio-ecology that may improve current conservation efforts. We encourage researchers and wildlife managers to pay more attention to natural carrion diversity underlying vulture social system diversity, especially when implementing supplementary feeding programs, and to consider the complex mating and settlement dynamics in reintroduction programs. Overall, we stress that understanding the complex social life of vultures is critical to harmonize their conservation with anthropogenic activities. LAY SUMMARY Although many of the threats faced by vultures have been identified, the impact of human activities on the social life of vultures has received little attention. We provide a comprehensive review of current knowledge of vulture social behavior and the evolutionary and ecological roots of their social systems. Within this social framework, we discuss aspects as diverse as vulture breeding and mating systems, foraging techniques, social hierarchies, territorial and gathering behavior, and interspecific interactions. Overall, we stress that advancing our socio-ecological understanding of the rich social life of vultures is critical to harmonize their conservation in this rapidly changing world.","PeriodicalId":50624,"journal":{"name":"Condor","volume":" ","pages":"1 - 20"},"PeriodicalIF":2.4,"publicationDate":"2020-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43321764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rusty Blackbirds select areas of greater habitat complexity during stopover","authors":"James R. Wright, Luke L. Powell, S. Matthews, C. Tonra","doi":"10.1093/condor/duaa040","DOIUrl":"https://doi.org/10.1093/condor/duaa040","url":null,"abstract":"ABSTRACT The Rusty Blackbird (Euphagus carolinus) is a widespread, uncommon migrant that has experienced heavy population declines over the last century. This species can spend over a quarter of their annual cycle on migration, so it is important to determine their habitat requirements during stopover events to inform effective conservation planning. We assessed their habitat selection at an important stopover site in northern Ohio during both fall and spring migration. Since stopover habitat selection is scale-dependent, we investigated both patch-scale (between patches) and fine-scale (within a patch) selection using radio telemetry to locate foraging and roosting flocks, and compared habitat variables between used and available points across the study site. At the patch scale, we found that birds preferred dogwood–willow swamp, low-lying forest patches, and areas of greater habitat complexity for foraging in both seasons. At the fine scale, spring migrants foraged closer to habitat edges than random, and preferred areas with more wet leaf litter and shallow water, and less grass cover. Fall migrants also preferred shallow water and leaf litter cover, and avoided areas with dense grass, forbs, and herbaceous shrub cover. By contrast, birds consistently roosted in dense stands of emergent Phragmites or Typha marsh, suggesting that the best stopover or staging sites are those with a matrix of different wetland habitats. Although the migratory range of Rusty Blackbirds is currently dominated by agricultural development, our results suggest that fragmented landscapes can still provide adequate habitat for migrants if the available land is managed for a variety of wet habitat types. LAY SUMMARY The Rusty Blackbird is a widespread, uncommon migrant that has experienced heavy population declines over the last century. Rusty Blackbirds can spend over a quarter of the year on migration, so it is important to determine their habitat requirements during stopover events to inform conservation planning. We assessed their habitat selection at 2 spatial scales at an important stopover site in Ohio during fall and spring migration, using radio telemetry to locate foraging and roosting flocks. At the patch scale, we found that Rusty Blackbirds preferred dogwood–willow swamp, flooded forest patches, and areas of habitat complexity for foraging. At the fine scale, birds foraged close to habitat edges, and preferred areas with more wet leaf litter and shallow water, while avoiding dense grass, forbs, and herbaceous shrub cover. By contrast, Rusty Blackbirds consistently roosted in dense stands of emergent marsh, suggesting that the best stopover sites are those with several different wetland habitats.","PeriodicalId":50624,"journal":{"name":"Condor","volume":"122 1","pages":"1 - 18"},"PeriodicalIF":2.4,"publicationDate":"2020-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41916796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}