Ornithological Applications最新文献

{"title":"Age-structured model reveals prolonged immigration is key for colony establishment in Gentoo Penguins","authors":"R. Herman, H. Lynch","doi":"10.1093/ornithapp/duac014","DOIUrl":"https://doi.org/10.1093/ornithapp/duac014","url":null,"abstract":"ABSTRACT Understanding the mechanisms of site colonization and range expansion is crucial to understanding population dynamics, particularly for colonial seabirds that may struggle to shift their breeding ranges under climate change. We provide an alternative and simple approach to estimating the number of migrating individuals among colonies when original mark–recapture datasets are not available for use in more integrated and established methods. Here we fit an age-structured population model with published vital rates and breeding success rates to simple point counts of abundance using rejection-based approximate Bayesian computation (ABC) to estimate the contribution of immigration to four recently colonized Gentoo Penguin (Pygoscelis papua) breeding sites on the Western Antarctic Peninsula. We found that sustained immigration over several years was required to generate the rapid population growth observed, with some sites even showing evidence of an accelerating immigration rate following initial colonization. We demonstrate that our method is capable of estimating the contribution of immigration to population growth in a species where mark–recapture datasets are unavailable. By leveraging census data that are relatively easy to obtain, our approach provides a new method for understanding how range expansions occur in species such as Antarctic penguins whose habitat is undergoing changing climate conditions. LAY SUMMARY Understanding how birds colonize new locations is important for learning how they may respond to climate change. While many methods exist to estimate the number of individuals that are moving among colonies, they cannot always be applied to certain species for which certain datasets are missing or unavailable. We overcame this issue by applying a common statistical approach to simulate growth of four new Gentoo Penguin colonies and compare these to the true growth patterns. Our model results showed that the rapid population growth we observed must have been supported by hundreds of immigrants coming from other colonies. These findings are interesting because these new colonies have led to a southward expansion of this species' typical breeding distribution and this recent range expansion may be a response to changing climate. We demonstrate that this method is effective at estimating movement among colonies when other similar methods cannot be applied due to lack of dataset availability and data collection limitations of the species of interest. RESUMEN Comprender los mecanismos de colonización de sitio y la expansión del área de distribución es crucial para entender la dinámica poblacional, en particular para las aves marinas coloniales que pueden tener dificultades para cambiar sus áreas reproductivas frente a los efectos del cambio climático. Brindamos un enfoque simple y alternativo para estimar el número de individuos migratorios entre colonias cuando las bases de datos originales de marcado y recaptura no están disponib","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116690984","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":"Controlling trapping, overgrazing and invasive vegetation is key to saving Java's last population of the Black-winged Myna","authors":"Tom Squires, N. Collar, C. Devenish, Andrew Owen, A. Pratiwi, N. Winarni, S. Marsden","doi":"10.1093/ornithapp/duac004","DOIUrl":"https://doi.org/10.1093/ornithapp/duac004","url":null,"abstract":"ABSTRACT The Black-winged Myna (Acridotheres melanopterus) is an Endangered passerine endemic to the islands of Java and Bali, Indonesia. Illegal trapping to supply the cage-bird trade has led to its near-total extinction, with the global population estimated to number fewer than 100 individuals. We estimated the current range and population size of the species at Baluran National Park, which supports Java's last known population, and used species distribution modeling to evaluate potential suitability of currently unoccupied areas across the park to identify priorities for management intervention. We estimate that the Black-winged Myna population numbers 179 individuals (95% CI: 111–288; density: 14.3 ± 3.5 individuals km–2) and that its current range is 12.3 km2. Our model indicated that some 72 km2 of the park (30% of total area) has potentially suitable habitat for the species, and we infer that the principal cause for the disparity between its current and potential range is trapping, compounded by savanna loss and degradation due to illegal domestic cattle grazing and the spread of invasive thorny acacia (Vachellia nilotica). The partial clearance of acacia in recent years appears to have assisted a modest population recovery by the myna. Its further population growth and range expansion in Baluran will depend on effective management of illegal poaching, further clearance of acacia, and easing domestic cattle grazing pressure on areas of savanna, particularly through engagement with communities living inside the park. Any actions that increase the size of the Black-winged Myna population are likely to benefit other threatened savanna-dependent wildlife in the park, notably banteng (Bos javanicus) and Green Peafowl (Pavo muticus). While our models and recommendations may be applicable to other protected areas in Java, and indeed other threatened myna species, trapping and habitat change may have site-specific dimensions, especially outside of protected areas, and thus demand local bespoke solutions. LAY SUMMARY The Black-winged Myna, confined to Java and Bali in Indonesia, is threatened with extinction due to illegal trapping for the cage-bird trade. Baluran National Park supports the last known population on Java. We estimated the number of mynas in the park, mapped where they occur, and assessed their habitat to determine how much of it is currently unoccupied. There are ∼180 Black-winged Mynas in the park, indicating recent population growth. However, they occupy <20% of the potentially suitable habitat, restricting further population growth. Trapping is the foremost factor holding back the mynas, but overgrazing by domestic livestock and invasion by thorny acacia negatively affect the potentially suitable habitat. Thorny acacia eradication must continue. Working with the human communities living in the park is key to alleviating the grazing pressure and addressing the trapping issue.","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125326244","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":"Tamarisk biocontrol alters bird community composition in the absence of cottonwood and willow vegetation","authors":"Sean M. Mahoney, Matthew J. Johnson, J. A. Holmes, T. Dudley, Michael J. Kuehn, T. Theimer","doi":"10.1093/ornithapp/duac012","DOIUrl":"https://doi.org/10.1093/ornithapp/duac012","url":null,"abstract":"ABSTRACT Invasive plants threaten biodiversity worldwide, but control of non-native species may affect native species in complex ways. Non-native tamarisk (Tamarix spp.) is widespread in western U.S. riparian environments, and tamarisk beetles (Diorhabda spp.), a tamarisk-specific herbivore, were subsequently introduced as biocontrol. The primary effect of biocontrol is defoliation and branch dieback, with repeated defoliation killing the plant. We investigated the initial stages of site recovery after biocontrol and how tamarisk decline affected birds, their arthropod prey, and microclimate. We compared avian community diversity and composition, arthropod abundance, humidity, and temperature at sites along the Virgin River in Nevada and Arizona, USA characterized as either mixed native vegetation, tamarisk-dominated, or tamarisk-dominated where the majority of tamarisk died from biocontrol. We compared avian communities sampled after biocontrol to counts at the same locations before biocontrol. Prior to biocontrol, community compositions of all but one site grouped together using unbiased clustering algorithms. Following biocontrol, tamarisk-dominated sites grouped separately, and mixed sites grouped with the pre-biocontrol cluster. Comparison of pre- and post-biocontrol communities showed 7 common species declined by ≥30% in dead tamarisk sites, while one species did so at mixed sites and 3 at tamarisk-dominated sites. Individual census points in dead tamarisk had significantly lower Simpson diversity than the same points censused before biocontrol, unless native vegetation was present, suggesting tamarisk death was the cause of dominant species abundance changes. Tamarisk-dominated sites were hotter and drier than sites with native vegetation and supported fewer non-tamarisk-obligate arthropods, consistent with the hypothesis that bird reductions were driven by changes in microclimate and prey abundance. How long these effects last will depend upon the rate of native vegetation recovery after biocontrol, therefore we recommend monitoring sites to determine the trajectory of vegetative recovery and considering the need and feasibility of active restoration in those sites with slow or no native regeneration. LAY SUMMARY Invasive species disturb ecosystems and threaten biodiversity. Invasive species management, such as biological control, can cause additional disturbances, so quantifying how native species respond to invasive control is important to inform best management practices We quantified southwestern bird communities in sites that varied in the amount of the non-native plant tamarisk (Tamarix spp.), before and after biological control efforts Following biocontrol, we found significant differences in community composition and diversity, and several bird species declined by ≥30% Bird declines were ameliorated in the presence of native vegetation, consistent with the hypothesis that tamarisk biocontrol decreases prey availability and alters ","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121617290","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":"Cross-seasonal effects in the American Woodcock: Conditions prior to fall migration relate to migration strategy and implications for conservation","authors":"Clayton L. Graham, Tanner K. Steeves, S. McWilliams","doi":"10.1093/ornithapp/duac011","DOIUrl":"https://doi.org/10.1093/ornithapp/duac011","url":null,"abstract":"ABSTRACT How postbreeding habitat quality and body composition of migratory birds carry over to influence fall migration strategies and residency merits consideration when creating cross-seasonal conservation plans, especially in breeding populations that are partial migrants. We assessed the influence of postbreeding habitat quality on departure body composition and fall migration patterns in a southern New England breeding population of American Woodcock (Scolopax minor). Woodcock that overwintered near breeding areas (n = 5) had less fat upon capture in fall and used lower quality habitat during the fall than birds that eventually departed on migration (n = 17). Woodcock that departed earlier were long-distance migrants that had inhabited higher quality landscapes prior to migration, departed with less or similar fat stores, stopped over for shorter periods on migration, and arrived earlier on their more southerly wintering areas. In contrast, woodcock that departed later were short-distance migrants that had inhabited lower quality landscapes prior to migration yet stored similar or more fat upon departure, stopped over for longer periods on migration, and arrived relatively late to their more northerly wintering areas. These differences in migration strategies were evident under the same fall environmental conditions and did not appear related to individuals responding to their own condition as would be expected if they were classic condition-based carry-over effects. As such, the southern New England breeding population of woodcock is best categorized as nonfacultative partial migrants (i.e., includes residents, short-distance migrants, and long-distance migrants) that demonstrate weak connectivity between life stages; such populations are excellent for the study of the costs and benefits of migration. The stopover and wintering areas used by woodcock in the coastal mid-Atlantic states deserve conservation and management attention in order to preserve critical habitat throughout their wintering range. LAY SUMMARY Effective conservation of migratory birds requires knowing how conditions prior to migration relate to the timing, routes, and destinations of birds during migration. We used VHF radiotelemetry to track American Woodcock (Scolopax minor) in southern New England throughout the summer and fall, recaught them prior to fall migration and used the deuterium-dilution method to nondestructively estimate their departure body composition, and then used GPS radiotelemetry to track them every few days throughout fall migration until they reached their wintering areas. At the time of fall migration, resident woodcocks were less fat than individuals that eventually migrated. Migratory woodcock that inhabited higher quality landscapes in the fall departed earlier and, with less or similar fat stores, stopped over for shorter periods on migration, and arrived earlier on their more southerly wintering areas than birds that inhabited lower quality ","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"192 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131463346","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":"Temporal factors and distance to human settlement affect nest survival of the endangered Yellow-headed Parrot in Belize, Central America","authors":"Fabio L. Tarazona‐Tubens, Charles R. Britt, Fitsum Abadi, Mario Muschamp, M. Desmond","doi":"10.1093/ornithapp/duac010","DOIUrl":"https://doi.org/10.1093/ornithapp/duac010","url":null,"abstract":"ABSTRACT The endangered Yellow-headed Parrot (Amazona oratrix) has experienced a considerable reduction in abundance and distribution. Identifying natural and anthropogenic causes of nest failure is a critical step towards developing conservation actions that increase nest survival. In this study, we examined daily nest survival in relation to temporal, habitat, and anthropogenic factors, as well as nest site properties. We monitored nests (n = 124) across 6 study sites in Belize during 2017 and 2018 and independently modeled the effects of predation, abandonment and poaching on daily nest survival rates. Overall, the estimated cumulative nest survival probability was 0.18 (95% CI: 0.12–0.25). Predation was the main cause of nest failure, followed by abandonment, and poaching. Our results showed that nest predation and abandonment usually occurred early in the nesting cycle. Day within the nesting season negatively influenced daily survival for abandoned nests and had a quadratic effect on survival for poached nests. Poaching events occurred at a specific date range later in the season, with nests farther from the nearest human settlement having higher daily survival. Findings from this study highlight the additive mortality effect that nest poaching is having on Yellow-headed Parrot populations in Belize and show that managers can anticipate the timing and location of nests most vulnerable to poaching. LAY SUMMARY Yellow-headed Parrots (Amazona oratrix) are classified as globally endangered due to population declines attributed to the pet trade and habitat loss, resulting in small remnant populations scattered throughout its historical range. We monitored nests in Belize and identified factors associated with predation, abandonment, and poaching. Predation was the main cause of nest failure, followed by abandonment and poaching. Increasing nest age was associated with lower probability of nest predation and abandonment. Increasing day within the nesting season was associated with increasing abandonment, while poaching occurred within a specific range of days. Increasing distance to human settlements reduced nest poaching. While poaching is a source of additive mortality for Yellow-headed Parrot nests in Belize, managers can anticipate the timing and location of nests vulnerable to poaching.","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114505912","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":"Highly specialized recreationists contribute the most to the citizen science project eBird","authors":"Connor J. Rosenblatt, A. Dayer, Jennifer N. Duberstein, T. Phillips, H. Harshaw, D. Fulton, N. Cole, A. Raedeke, J. Rutter, Christopher Wood","doi":"10.1093/ornithapp/duac008","DOIUrl":"https://doi.org/10.1093/ornithapp/duac008","url":null,"abstract":"ABSTRACT Contributory citizen science projects (hereafter “contributory projects”) are a powerful tool for avian conservation science. Large-scale projects such as eBird have produced data that have advanced science and contributed to many conservation applications. These projects also provide a means to engage the public in scientific data collection. A common challenge across contributory projects like eBird is to maintain participation, as some volunteers contribute just a few times before disengaging. To maximize contributions and manage an effective program that has broad appeal, it is useful to better understand factors that influence contribution rates. For projects capitalizing on recreation activities (e.g., birding), differences in contribution levels might be explained by the recreation specialization framework, which describes how recreationists vary in skill, behavior, and motives. We paired data from a survey of birders across the United States and Canada with data on their eBird contributions (n = 28,926) to test whether those who contributed most are more specialized birders. We assigned participants to 4 contribution groups based on eBird checklist submissions and compared groups' specialization levels and motivations. More active contribution groups had higher specialization, yet some specialized birders were not active participants. The most distinguishing feature among groups was the behavioral dimension of specialization, with active eBird participants owning specialized equipment and taking frequent trips away from home to bird. Active participants had the strongest achievement motivations for birding (e.g., keeping a life list), whereas all groups had strong appreciation motivations (e.g., enjoying the sights and sounds of birding). Using recreation specialization to characterize eBird participants can help explain why some do not regularly contribute data. Project managers may be able to promote participation, particularly by those who are specialized but not contributing, by appealing to a broader suite of motivations that includes both appreciation and achievement motivations, and thereby increase data for conservation. LAY SUMMARY Contributory science projects have conservation and societal benefits, yet some projects struggle with participant retention. Recreation specialization (a framework that describes individuals' degree of engagement in and commitment to an activity) uses three dimensions to classify recreationists: affective (psychological attachment to specific activities), behavioral (frequency of participation, prior experience, and equipment used), and cognitive (knowledge and skill about an activity). We used survey data about involvement and preferences of birders in the U.S. and Canada to measure recreation specialization. We then combined these data with respondents' checklist contributions to eBird. Individuals who had the highest scores for all three recreation specialization dimensions contributed the","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125401589","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":"Genetic monitoring of the Critically Endangered Araripe Manakin reveals low diversity and declining effective population size","authors":"L. W. Luna, S. Silva, Weber Andrade de Girão e Silva, Milene Garbim Gaiotti, R. Macedo, J. Araripe, Péricles Sena do Rêgo","doi":"10.1093/ornithapp/duac009","DOIUrl":"https://doi.org/10.1093/ornithapp/duac009","url":null,"abstract":"ABSTRACT Genetic information is still underestimated in conservation policies, seldom being monitored or included in management strategies. Monitoring changes in genetic diversity over time in endangered species is useful to anticipate possible risks associated with reduced genetic variation. The Araripe Manakin (Antilophia bokermanni) is a Critically Endangered species, probably with a historically low level of genetic diversity and currently facing demographic population decline. This is the first study to present a fine-scale spatio-temporal genetic monitoring for the Araripe Manakin. Using microsatellite loci, genotyped at two time periods (2003–2004 and 2015–2017), we conclude that genetic diversity has been relatively stable in this short-term assessment, with limited signs of population structure between time frames, and no current population structure within past or present species distribution. However, we also detect signs of genetic bottleneck and evidence that suggest that mating is not presently random. Our results corroborate that the species is a resilient bird, but habitat loss and degradation are jeopardizing Araripe Manakin's persistence. The species comprises a unique small population, and restoration of habitat quality and connectivity should continue to maintain its viability. Nonetheless, given the low genetic diversity observed, we further identify some challenges and recommend solutions for the implementation of genetic information in the current conservation effort of the Araripe Manakin. LAY SUMMARY The Araripe Manakin is restricted to a small area (∼40 km2) of humid forest enclaves in northeastern Brazil. Mostly due to habitat degradation, the species has been severely declining in the last decades. An ongoing action plan has been focusing on habitat quality restoration for the species conservation, but has not yet assessed the genetic consequences of the Araripe Manakin restricted distribution and demographic decline. Such factors can lead to the loss of genetic diversity, which can jeopardize the species survival. Our results show that between 2003 and 2017, the demographic decline has already affected the genetic diversity of the Araripe Manakin, the number of reproducing individuals has declined, and mating is not presently random, further compromising the species genetic diversity stability. The low levels of genetic diversity we report for the Araripe Manakin highlight that the continuous genetic monitoring should be included in the species' conservation plan.","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"79 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128105482","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":"Avian botulism is a primary, year-round threat to adult survival in the endangered Hawaiian Duck on Kaua‘i, Hawai‘i, USA","authors":"Christopher P. Malachowski, B. Dugger, Kimberly J. Uyehara, M. Reynolds","doi":"10.1093/ornithapp/duac007","DOIUrl":"https://doi.org/10.1093/ornithapp/duac007","url":null,"abstract":"ABSTRACT Adult survival is the most important demographic parameter influencing population dynamics for many bird taxa. Thus, understanding how survival probabilities and causes of mortality vary throughout the annual cycle is critical for developing informed and effective management strategies. In this study, we used radio-telemetry data to evaluate the effects of biotic (e.g., sex, peak [September–April] vs. off-peak [May–August] nesting seasons) and abiotic factors (e.g., rainfall, year, bi-monthly interval) on adult survival, estimate annual survival probabilities, and identify primary sources of mortality for Hawaiian Ducks (Anas wyvilliana), an endangered, non-migratory dabbling duck, on the island of Kaua‘i, Hawai‘i, USA over 2013 and 2014. Additionally, we used contemporaneous Hawaiian Duck carcass recovery and surveillance data to examine temporal and climatic associations with avian botulism outbreaks. Our results suggested bi-monthly survival decreased with total rainfall during the preceding 2-month interval. Survival did not vary with sex, between peak and off-peak nesting seasons, or between the two years of this study. Annual survival probabilities (62–80%) were relatively low compared to the closely related Laysan Duck (Anas laysanensis) on Laysan Island. Primary causes of mortality included avian botulism and presumed predation by cats (Felis catus). The botulism surveillance dataset revealed support for the effect of rainfall on the number of sick and dead birds recovered (n = 216), with generally a greater number of recoveries during months with middle-range total rainfall during the concurrent and preceding months. Our study provides critical baseline demographic data for population monitoring and highlights the importance of managing botulism risk and non-native mammalian predators for the recovery of the endangered Hawaiian Duck. LAY SUMMARY Understanding how adult survival probabilities and causes of mortality vary throughout the annual cycle is instrumental for develo in informed and effective conservation strate ies We used radio-telemetry data to evaluate factors influencing adult survival and identify sources of mortality for the endangered Hawaiian Duck on Kaua‘i, and we used botulism surveillance data to assess factors associated with avian botulism outbreaks. Avian botulism was the primary cause of adult mortality and posed a risk year-round. Increased rainfall was associated with lower survival and higher numbers of sick and dead birds attributed to botulism except during wettest periods when botulism recoveries decreased Survival did not differ between sexes or peak and off-peak nesting seasons, but the rate of predation was higher for females, and all female predation events (n = 4) occurred during the peak-nesting season. Our study provides critical demographic data for population monitoring and highlights the importance of managing botulism risk and non-native mammalian predators (e.g., feral cats) for Hawaiian ","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"24 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113991974","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":"Bird predation and landscape context shape arthropod communities on broccoli","authors":"J. M. Taylor, Olivia M. Smith, Max Edworthy, C. Kennedy, C. E. Latimer, J. Owen, E. Wilson-Rankin, W. E. Snyder","doi":"10.1093/ornithapp/duac005","DOIUrl":"https://doi.org/10.1093/ornithapp/duac005","url":null,"abstract":"ABSTRACT Birds increase crop yields via consumption of pests in some contexts but disrupt pest control via intraguild predation in others. Landscape complexity acts as an inconsistent mediator, sometimes increasing, decreasing, or not impacting pest control. Here, we examined how landscape context and seasonal variation mediate the impact of birds on arthropod pests and natural enemies, leaf damage, and yields of broccoli (Brassica oleracea) on highly diversified farms that spanned the USA west coast. Our study had two complementary components: a bird exclusion experiment and molecular diet analysis of 357 fecal samples collected from the most commonly captured bird species that also foraged in Brassica fields—American Goldfinch (Spinus tristis), American Robin (Turdus migratorius), Savannah Sparrow (Passerculus sandwichensis), Song Sparrow (Melospiza melodia), and White-crowned Sparrow (Zonotrichia leucophrys). Bird access yielded higher, rather than lower, numbers of pest aphids and increased their parasitism, while no other arthropods examined were consistently impacted. Independent of bird presence, percent natural cover in the landscape sometimes increased and sometimes decreased densities of arthropods in the mid-growth period, with diminishing impacts in the late-growth period. Herbivore feeding damage to broccoli leaves decreased with increasing amounts of natural land cover and in the late-growth period. Molecular diet analysis revealed that Brassica pests and predatory arthropods were relatively uncommon prey for birds. Landscape context did not alter the prey items found in bird diets. Altogether, our bird-exclusion experiment and molecular diet analysis suggested that birds have relatively modest impacts on the arthropods associated with broccoli plantings. More broadly, the limited support in our study for net natural pest control services suggests that financial incentives may be required to encourage the adoption of bird-friendly farming practices in certain cropping systems. LAY SUMMARY Birds may contribute pest control services through consumption of arthropod pests or disrupt pest control through predation on arthropod natural enemies. The net effect of birds on crop pests and subsequent yields may be mediated by landscape context. To better understand the net effects of birds on broccoli, we combined a bird exclusion experiment with DNA-based diet analysis of 5 key bird species. Both birds and landscape context impacted arthropods on broccoli plants. However, we observed no net effect of birds on broccoli yield regardless of landscape context. DNA-based diet analysis revealed that while landscape did not alter the likelihood of bird species consuming pests or arthropod natural enemies, some bird species were more likely than others to consume arthropod natural enemies. The limited impacts of birds on broccoli leaf damage and yields suggested that pest control services by birds may be an insufficient motivator to employ bird-fri","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115783675","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":"Bird versus Bulldozer: A Quarter-Century Conservation Battle in a Biodiversity Hotspot","authors":"J. Quinn","doi":"10.1093/ornithapp/duac001","DOIUrl":"https://doi.org/10.1093/ornithapp/duac001","url":null,"abstract":"","PeriodicalId":125764,"journal":{"name":"Ornithological Applications","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114262576","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}