The Condor: Ornithological Applications最新文献

{"title":"Grasslands in the Northern Prairie region support a diverse assemblage of migrant birds and facilitate fattening during migratory stopover","authors":"Amy C West, David L Swanson","doi":"10.1093/ornithapp/duae049","DOIUrl":"https://doi.org/10.1093/ornithapp/duae049","url":null,"abstract":"Grasslands have been reduced as a result of conversion to agriculture and other anthropogenic uses. Consequently, grassland migrant birds may have limited options for migration stopover. In addition, the simple presence of birds in grassland fragments during migration periods does not imply that the habitat is providing the food resources necessary for birds to replenish fat stores and continue migration. We examined (1) the diversity of birds using grasslands during migration stopover in southeastern South Dakota and (2) whether a reconstructed prairie can provide the resources necessary for successful stopover. To accomplish these goals, we conducted line transect surveys on plots dominated by either cool- (primarily non-native) or warm-season (primarily native) grasses and captured birds on a reconstructed tallgrass prairie to determine plasma levels of triglycerides, an indicator of fat deposition, and β-hydroxybutyrate, an indicator of fat depletion. Grassland, woodland/shrub, and habitat generalist bird species were all present on study grasslands during spring and fall migration seasons. Overall, species-richness tended to be greater at warm season dominated sites during spring migration, but richness differences between sites varied by year during fall migration. Overall bird densities, however, were roughly similar between the two habitat types at both seasons, although some differences for individual bird species occurred. Plasma triglyceride and β-hydroxybutyrate levels of migrant birds using the reconstructed tallgrass prairie were consistent with those from birds in known high-quality stopover habitats. These findings suggest that grasslands that have a diversity of plant species and structural heterogeneity may be important for stopover sites for a variety of migratory birds using grasslands as stopover sites, including declining grassland species. These data further suggest that the creation and management of restored and reconstructed prairies throughout the migratory routes for grassland birds may provide quality stopover for these species.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Informative priors can account for location uncertainty in stop-level analyses of the North American Breeding Bird Survey (BBS), allowing fine-scale ecological analyses","authors":"Ryan C Burner, Alan Kirschbaum, Jeffrey A Hostetler, David J Ziolkowski, Nicholas M Anich, Daniel Turek, Eli D Striegel, Neal D Niemuth","doi":"10.1093/ornithapp/duae041","DOIUrl":"https://doi.org/10.1093/ornithapp/duae041","url":null,"abstract":"Ecological inferences are often based on the locations at which species are present, but many species records have substantial uncertainty in spatial metadata, limiting their utility for fine-scale analyses. This is especially prevalent in historical records such as museum specimens, and in some citizen-science data. For example, the North American Breeding Bird Survey (BBS) has 55+ years of bird data from regular transects (“routes”) across the continent but was not designed to capture the spatial component of point count events, limiting analyses of species-habitat relationships for which it would otherwise be well suited. We present a new methodology for quantifying location uncertainty in BBS records using digitized estimated stop locations, deriving the corresponding environmental covariate uncertainty distributions, and incorporating this information into hierarchical species distribution models using informative Bayesian priors. This approach allows for estimation of species–environment relationships in a way that fully accounts for underlying spatial uncertainty. We quantify stop-location uncertainty in BBS data across the central United States, model bird–land cover relationships in the upper Midwest, and validate our method by comparing posterior land cover estimates to known covariate values for a subset of GPS-digitized stop locations. We provide code for implementing this method in R. Posterior land cover estimates (forest, grass/hay, and developed land cover), based on our informative priors, were highly correlated with known land cover values from GPS-digitized stop locations. Our approach thus makes it possible to responsibly leverage large historic and citizen science databases, such as the BBS, for fine-scale ecological analyses.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anas platyrhynchos (Mallard) have been replacing Anas rubripes (American Black Duck) in human-altered landscapes in Ontario, 1996–2019","authors":"Christian Roy, Samuel Iverson, Shawn Meyer, Matthew Dyson, Amelia R Cox","doi":"10.1093/ornithapp/duae048","DOIUrl":"https://doi.org/10.1093/ornithapp/duae048","url":null,"abstract":"Anas rubripes (American Black Duck) has received much attention over the years as a popular game bird species that experienced historical declines on its wintering grounds. Declines may be due to changes in the quality and quantity of breeding habitat, competition with A. platyrhynchos (Mallard), or both. Although the A. rubripes population has stabilized, spatial variation in regional population trends of A. rubripes on their breeding grounds can provide insight into the relative importance of these alternative hypotheses at provincial and local scales. We analyzed indicated breeding pairs count data collected in Ontario between 1996 and 2019 through the Eastern Waterfowl Survey to evaluate the correlation in breeding densities and trends of the five most abundant waterfowl species. We also tested whether habitat and anthropogenic disturbance variables could explain the distribution of those species. Overall, A. platyrhynchos breeding pair densities increased across the survey area, whereas A. rubripes breeding pair densities decreased in the southern and northern part of the survey area but remained stable in the central part. Densities of breeding pairs of A. rubripes and A. platyrhynchos were negatively correlated across survey plots but the trends in breeding densities were not correlated. Densities of A. platyrhynchos breeding pairs increased in human altered landscapes whereas the density of A. rubripes breeding pairs was negatively correlated with agriculture. Our results suggest that A. platyrhynchos did not competitively exclude A. rubripes on the breeding grounds, but instead, A. rubripes were replaced by A. platyrhynchos following encroachment of agriculture into A. rubripes breeding habitat. Habitat management plans focused on breeding A. rubripes should emphasize reduction in the expansion of anthropogenic perturbations and increases in habitat conservation efforts in the central area of the breeding range in Ontario.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ecology and conservation of cavity-nesting birds in the Neotropics: Recent advances, future directions, and contributions to ornithology","authors":"Eugenia Bianca Bonaparte, Cecilia Cuatianquiz Lima, Hipólito D Ferreira-Xavier, Jéssica S da Hora Barros, Facundo G Di Sallo, Fernando G López, Kristina L Cockle, María Gabriela Núñez Montellano","doi":"10.1093/ornithapp/duae042","DOIUrl":"https://doi.org/10.1093/ornithapp/duae042","url":null,"abstract":"About 35% of tree-cavity-nesting bird species inhabit the Neotropics, a region crucial to understanding their breeding ecology, conservation, and roles in social-ecological systems. Sixteen years ago, Cornelius et al. (2008) reviewed published knowledge and identified research priorities for Neotropical cavity-nesting birds. Advances since 2008 have not been synthesized and many remain excluded from dominant ornithology because of barriers that disproportionately affect people and ideas from the Global South. Here, we review recent advances in knowledge about Neotropical cavity-nesting birds, introduce the Special Feature series \"Ecology and conservation of cavity nesters in the Neotropics\", and outline possible directions for future research. Research in the Neotropics has advanced knowledge of breeding biology, demonstrated that nest sites are limited and birds compete for cavities (mainly in humid forests), identified non-excavated cavities (formed by wood decay) as the main source of cavities and demonstrated the importance of understanding Indigenous and local community relationships to birds. With field studies across the Neotropics, the Special Feature series shows how environment, people's common imaginaries, vegetation management, and behavior of avian excavators can interact to influence cavity availability, with ecological consequences for many cavity-using organisms. In the future, researchers should center ethno-knowledge and natural history to create an accurate list of cavity-nesting birds in the Neotropics, and integrate this knowledge into studies of population and community ecology. It is also important to study factors that influence cavity dynamics, especially using a social-ecological systems framework and especially in arid and semi-arid regions. We recommend expanding the concept of nest webs (ecological networks of cavity nesters) to incorporate additional cavity substrates (e.g., termitaria, cliffs), cavity alternatives (e.g., bulky enclosed stick nests of many Furnariidae), and cavity-using taxa beyond birds and mammals (e.g., social insects, snakes), which abound in the Neotropics but were not contemplated in the original nest web formulation. Translated versions of this article are available in Supplementary Material 1 (Spanish) and Supplementary Material 2 (Portuguese).","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduced representation sequencing reveals weak genetic differentiation between Canadian and European Larus hyperboreus (Glaucous Gull)","authors":"Emma Lachance Linklater, Sarah A Sonsthagen, Gregory J Robertson, Lila Colston-Nepali, Freydís Vigfúsdóttir, Vicki L Friesen","doi":"10.1093/ornithapp/duae037","DOIUrl":"https://doi.org/10.1093/ornithapp/duae037","url":null,"abstract":"Climate change poses a significant threat to Arctic ecosystems. Evaluation of genetic diversity within and differentiation among populations is needed to effectively conserve Arctic species and ensure genetic variation is appropriately managed. This research examined population genetic structure in Larus hyperboreus (Glaucous Gull), a circumpolar Arctic species that is declining in parts of its range. Population genetic information is needed to help delineate management units, including information on genetic differences among related species, among subspecies (currently distinguished by subtle morphometric and plumage differences), and among colonies in North America. We conducted double-digest restriction site-associated DNA sequencing for 62 L. hyperboreus, 18 L. argentatus smithsonianus (American Herring Gull), 6 L. a. argentatus (European Herring Gull), and 15 L. glaucescens (Glaucous-winged Gull) sampled across the Canadian and European Arctic. Interspecific analyses using 2,145 loci were unable to distinguish members of this species complex. Despite the geographic distance among sampling locations, molecular assignments and principal coordinates analyses based on 621 loci uncovered only weak population genetic differentiation among sampled European and Canadian colonies of L. hyperboreus. As L. hyperboreus occupying the eastern Canadian Arctic appear to be acting as a single panmictic population, conservation plans that protect Arctic habitat may help slow or reverse population declines. Proactive conservation strategies will benefit both L. hyperboreus and associated coastal Arctic ecosystems.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ecosystem engineers show variable impacts on habitat availability for cavity nesters in South American temperate forests","authors":"Cecilia Cuatianquiz Lima, Tomás A Altamirano, Rocío Jara, Edwin R Price, Fernando J Novoa, José Tomás Ibarra","doi":"10.1093/ornithapp/duae039","DOIUrl":"https://doi.org/10.1093/ornithapp/duae039","url":null,"abstract":"Ecosystem engineers are organisms that impact their environment and co-existing species by creating or modifying habitats, and thus they play important roles as drivers of community assembly. We examined whether cavity characteristics and/or habitat attributes associated with cavities provided by 4 ecosystem engineers influence the presence of nests of 3 secondary cavity-nesting birds—Aphrastura spinicauda (Thorn-tailed Rayadito), Tachycineta leucopyga (Chilean Swallow), and Troglodytes aedon (Southern House Wren)—and whether these variations influence their reproductive success. We tested this by (1) assessing nest presence in cavities supplied by ecosystem engineers and (2) quantifying the reproductive success of secondary cavity nesters as a function of cavity characteristics and habitat attributes supplied by ecosystem engineers. Between 2009 and 2022, we recorded 757 cavities in 546 trees in old-growth and second-growth forests in a Global Biodiversity Hotspot in the Andes of southern Chile. Insect/fungi and Pygarrhichas albogularis (White-throated Treerunner) play a key role as the primary producers of cavities. Insect/fungi generated the cavities for 82% of A. spinicauda nests and 95% of T. aedon nests; in contrast, 57% of T. leucopyga nests were cavities excavated by P. albogularis. Characteristics of cavities (size of cavity entrance, volume, and height above ground) were associated with nest presence of secondary cavity nesters and with reproductive success of A. spinicauda and T. aedon. Habitat attributes such as tree density and canopy cover influenced nest presence for A. spinicauda and T. leucopyga, but did not correlate with the reproductive success of any secondary cavity nester. Bamboo density and forest type were related to reproductive success of A. spinicauda and T. aedon. Diameter at Breast Height of trees was related to the reproductive success of T. leucopyga. This study contributes to understanding the importance of various ecosystem engineers for the conservation of secondary cavity-nesting birds in temperate forests and beyond.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial survival analysis accounts for female-biased breeding dispersal and provides realistic estimates of true annual survival in migratory warblers","authors":"Ronald L Mumme","doi":"10.1093/ornithapp/duae040","DOIUrl":"https://doi.org/10.1093/ornithapp/duae040","url":null,"abstract":"Breeding dispersal—between-season change in breeding location—is usually female-biased in birds and creates problems in accurately estimating annual survival, as conventional Cormack-Jolly-Seber (CJS) survival models cannot discriminate between mortality and undetected emigration. Recently, spatial CJS (s-CJS) models have been developed that use data on breeding dispersal within a population to account for undetected emigration and provide corrected estimates of true annual survival, a development that promises to advance avian conservation initiatives that require accurate estimates of annual survival. Using a 14-yr dataset on a color-banded population of Setophaga citrina (Hooded Warbler) in northwest Pennsylvania, I examined female-biased breeding dispersal and performance of a s-CJS model in estimating true annual survival of females and males. I also compared my findings to published literature on other migratory North American warblers, a group with many species of high conservation concern. Breeding dispersal in the S. citrina study population is strongly female-biased, with median dispersal distances of 151 m for females (n = 227) and 51 m (n = 336) for males. Although most individuals disperse short distances, the observed pattern of breeding dispersal within the study site was best modeled using a heavy-tailed Cauchy dispersal kernel, a model that indicates the presence of a substantial tail of undetected long-distance dispersal, particularly in females. Using the Cauchy model, s-CJS analysis yielded realistic estimates of S. citrina true annual survival, 0.61 for both sexes, and resolved ambiguities evident in much lower estimates of apparent annual survival, 0.45 for females and 0.54 for males, derived from conventional CJS analysis. Because long-distance breeding dispersal is widespread in migratory warblers and especially frequent in females, analyses of warbler survival should employ s-CJS methods whenever possible, as estimates of apparent annual survival derived from conventional CJS methods will in most cases poorly approximate true annual survival.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Despite regional variation, Gymnorhinus cyanocephalus (Pinyon Jay) densities generally increase with local pinyon–juniper cover and heterogeneous ground cover","authors":"Nicholas J Van Lanen, Adrian P Monroe, Cameron L Aldridge","doi":"10.1093/ornithapp/duae036","DOIUrl":"https://doi.org/10.1093/ornithapp/duae036","url":null,"abstract":"Traditionally, local-scale habitat-relationship models are developed over small spatial extents, limiting model transferability and inference outside the study area. Thus, habitat managers frequently lack fine-scale information regarding the influence of vegetation composition and structure on site suitability or species abundance. Gymnorhinus cyanocephalus (Pinyon Jay) represents one declining species for which managers have limited information regarding the influence that vegetation composition and structure have on abundance at broad scales. To address this need, we developed a hierarchical Bayesian abundance model using summertime bird and vegetation data collected under the Integrated Monitoring in Bird Conservation Regions program to explain jay abundance as a function of local conditions. Our G. cyanocephalus abundance model allowed abundance relationships with pinyon pine (Pinus edulis and P. monophylla) and juniper (Juniperus spp.) to vary by ecoregion, thereby accounting for potential regional differences in habitat associations. We found G. cyanocephalus abundance was generally positively associated with pinyon pine and juniper cover; however, habitat relationships varied by ecoregion. Additionally, we found positive associations between jay abundance and grass cover, sagebrush cover, and percent bare ground. Our results agree with prior research suggesting mechanical removal of pinyon pine and juniper trees for sagebrush restoration or fuel treatments may negatively affect G. cyanocephalus. Managers wishing to reduce pinyon and juniper tree cover without negatively affecting G. cyanocephalus may benefit from targeting sites where both large-scale distribution models and our local habitat relationships suggest G. cyanocephalus are likely to occur in low numbers. Additionally, our modeled relationships indicate restoration that increases grass cover, sagebrush cover, and bare ground, while maintaining pinyon and (or) juniper cover, may lead to increased local densities of G. cyanocephalus.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brood translocation increases post-release recruitment and promotes population restoration of Centrocercus urophasianus (Greater Sage-Grouse)","authors":"Mary B Meyerpeter, Peter S Coates, Steven R Mathews, Kade Lazenby, Brian G Prochazka, David K Dahlgren, David J Delehanty","doi":"10.1093/ornithapp/duae013","DOIUrl":"https://doi.org/10.1093/ornithapp/duae013","url":null,"abstract":"Wildlife managers translocate Centrocercus urophasianus (Greater Sage-Grouse) to augment small populations, but translocated C. urophasianus often fail to reproduce post-release, hampering conservation objectives. We performed 2 C. urophasianus translocations in California and North Dakota from 2017 to 2020 using 2 methods at both sites: an established method of translocating females prior to nesting (i.e., a pre-nesting translocation), and a novel method wherein females were translocated with chicks after successfully hatching nests in source populations (i.e., a brood translocation). We radio-marked and monitored 135 translocated females and 284 source population females and used count data from leks in recipient and source populations to evaluate each method. Using an integrated population model (IPM), we estimated demographic parameters, including recruitment, by females translocated with each method. We estimated the finite rate of change in abundance (λ) in recipient and source populations given multiple simulated translocation strategies using each method and evaluated them using a cost-benefit metric (i.e., a ratio of the simulated change in abundance at recipient and source sites). We found that recruitment in recipient populations was substantially higher when brood translocations were employed compared to when pre-nesting translocations were employed. Most females translocated pre-nesting forewent reproduction entirely, whereas most females translocated with their broods successfully reared offspring in recipient populations. A per-capita comparison revealed that brood translocations resulted in λ that were 11–30% greater than pre-nesting translocations, but also revealed that the removal of brood-rearing females from source populations resulted in larger reductions in λ when compared with pre-nesting translocations. However, reductions in λ were small and the estimated cost-benefit metrics indicated that translocation of females with broods was a more effective method at spurring growth in recipient populations while minimizing impacts to source populations.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141769996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tree cavity density is a limiting factor for a secondary cavity nester in second-growth Andean temperate rainforests","authors":"Tomás A Altamirano, Fernando Novoa, José Tomás Ibarra, Sergio A Navarrete, Cristián Bonacic, Kathy Martin","doi":"10.1093/ornithapp/duae031","DOIUrl":"https://doi.org/10.1093/ornithapp/duae031","url":null,"abstract":"Cavity-nesting bird populations are most frequently limited by the number of tree cavities available in second-growth forests. However, this possible limitation of a key resource is less clear in old-growth forests. We compared forest attributes (i.e., basal area, density of larger trees, density of dead trees, and tree cavity density) in second-growth and old-growth stands in Andean temperate rainforests in southern Chile. To examine the role of nest-site availability in limiting the populations of Aphrastura spinicauda (Thorn-Tailed Rayadito), a secondary cavity-nesting bird species, we conducted an experiment in which nest boxes were added and removed in old-growth and second-growth forests during a 5-yr period (2008–2013). In old-growth forests, as compared to second-growth forests, we found a more than double basal area (99.6 vs. 43.7 m2 ha–1), a three times higher density of larger trees (88.2 vs. 36.4 trees ha–1), and a 1.5 times higher number of small cavities (25.9 vs. 10.3 cavities ha–1). The density of cavities also strongly increased with tree diameter and basal area. In second-growth forests, A. spinicauda showed a strong response to the addition and removal of nest boxes, with population abundance increasing by 13% and then decreasing by 50%, respectively. In contrast, we found no impact in old-growth stands. Our experiment emphasizes the importance of maintaining large and dead trees in second-growth, disturbed, and managed forests. These trees provide suitable cavities for A. spinicauda, and likely many other secondary cavity nesters, increasing their abundances in a Globally significant Biodiversity Hotspot in southern South America.","PeriodicalId":501493,"journal":{"name":"The Condor: Ornithological Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141784840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}