Condor最新文献

{"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":"Plunging floater survival causes cryptic population decline in the Common Loon.","authors":"Walter H Piper, Jason Grear, Brian Hoover, Elaina Lomery, Linda M Grenzer","doi":"10.1093/condor/duaa044","DOIUrl":"10.1093/condor/duaa044","url":null,"abstract":"<p><p>Populations of many vertebrates are declining and geographic ranges contracting, largely as a consequence of anthropogenic threats. Many reports of such decline, however, lack the breadth and detail to narrow down its causes. Here we describe population decline in the Common Loon (<i>Gavia immer</i>), a charismatic aquatic bird, based on systematic resighting and measurement of a marked population. During our 27-year investigation, age-adjusted chick mass has fallen by 11%, mortality among young and old chicks has increased by 31% and 82%, respectively, and fledging success has declined by 26%. Meanwhile, the return rate of marked nonbreeders (\"floaters\") has plunged by 53%, and the adult population overall has declined by 22%. Consistent with the thinning ranks of floaters, the rate of territory eviction has decreased by 52% during the study. Despite the decline in floaters, territory occupancy remains unchanged. However, a matrix model, updated with recent estimates for breeding success, juvenile survival, and senescence, yields a recalculated deterministic population growth rate (λ) of 0.94 for our study population, which suggests that declines in vital rates could lead to a loss of 52% of the current population and a decline of 37% in territory occupancy by 2031. Lack of data on floaters in other upper Midwest and New England loon populations leaves their status in doubt.</p>","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2020-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11363150/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47913228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","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":null,"pages":null},"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}

{"title":"Riparian habitat restoration increases the availability and occupancy of Yellow-breasted Chat territories but brood parasitism is the primary influence on reproductive performance","authors":"T. Forrester, D. Green, Renee McKibbin, A. Bezener, C. Bishop","doi":"10.1093/condor/duaa038","DOIUrl":"https://doi.org/10.1093/condor/duaa038","url":null,"abstract":"ABSTRACT Implementation and evaluation of conservation efforts requires an understanding of the habitat selection and reproductive success of endangered populations. As populations recover, established territory holders may force new arrivals into lower quality habitat, which can reduce reproductive success, especially in disturbed landscapes where suitable habitat is scarce. The endangered Western Yellow-breasted Chat (Icteria virens auricollis) population in the fragmented riparian zone of the Okanagan Valley, British Columbia, Canada, has rapidly increased in response to habitat restoration. During this population increase from 2002 to 2014, we monitored 485 chat nests in 157 breeding territories to evaluate the influences of habitat selection, habitat restoration, and brood parasitism by Brown-headed Cowbirds (Molothrus ater) on reproductive performance. We found that, in protected reference sites, breeding territories that were occupied in the early years of the study had higher percent shrub cover than territories that were first occupied in the later years of the study, indicating that chats preferred territories with high shrub cover. Conversely, in restoration sites, later-occupied territories had similarly high shrub cover as earlier-occupied territories, suggesting that restoration activities enabled chats to continually settle in territories with high shrub cover. Yet, we did not find strong evidence that nest site vegetation characteristics or habitat restoration influenced reproductive performance. Instead, the high rate of brood parasitism (49%), which reduced nest success and productivity, was the dominant influence on reproductive performance. However, this recovering population still had high daily nest survival (0.974) and productivity (2.72 fledglings per successful nest) compared with other riparian songbirds and the high parasitism rate did not prevent the population from increasing. Thus, conservation efforts for Yellow-breasted Chats should focus on restoring riparian shrubs, even within heavily developed landscapes, to increase the number of potential breeding territories, while also quantifying how brood parasitism influences reproductive performance. LAY SUMMARY In landscapes where undisturbed, high-quality habitat is scarce, some birds may be forced to occupy low-quality habitat. Habitat restoration may provide more high-quality habitat. The endangered population of Yellow-breasted Chats in British Columbia increased in abundance from 2002 to 2014 in response to habitat restoration efforts. We investigated 2 questions: (1) Do chats prefer to nest in areas with certain vegetation characteristics? and (2) What effects do vegetation characteristics and parasitism by Brown-headed Cowbirds, which lay their eggs in chat nests, have on chat reproductive success? Settlement patterns indicated that chats prefer to occupy breeding territories with high shrub cover. However, Brown-headed Cowbirds parasitized half of all chat nest","PeriodicalId":50624,"journal":{"name":"Condor","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2020-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/condor/duaa038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44679920","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}