Avian Conservation and Ecology最新文献

{"title":"In the still of the night: revisiting Eastern Whip-poor-will surveys with passive acoustic monitoring","authors":"Elly C. Knight, Kevin C. Hannah, Jonathan DeMoor","doi":"10.5751/ace-02080-170121","DOIUrl":"https://doi.org/10.5751/ace-02080-170121","url":null,"abstract":". Recent advances in passive acoustic monitoring warrant the review of survey protocols because passive acoustic monitoring can increase sampling effort with minimal additional cost. In particular, protocols for nocturnal species should be re-evaluated because automated processing with signal recognition is expected to perform well for these species and surveys conducted by human observers are often limited by safety concerns. We revisited the best survey practices for the Eastern Whip-poor-will ( Antrostomus vociferus ), a nocturnal species of conservation concern. Whip-poor-will surveys are typically limited to nighttime, but also to times of high lunar illumination because their calling rate is associated with moonlight levels. We used automated recognition to extract Whip-poor-will detections from a dataset of autonomous recording unit (ARU) recordings from sites with known Eastern Whip-poor-will occupancy in Ontario, Canada. Temperature and time relative to sunset had particularly strong quadratic effects on detectability, with detectability maximized at 13 °C and 4 hours after sunset. Moon altitude and day of year had positive effects on detectability, while wind speed had negative effects on detectability. We found constraining surveys by optimal values of those detectability covariates was worthwhile only up until 10 recordings, at which point the cumulative probability of detecting an Eastern Whip-poor-will at each site was equal between constrained and unconstrained nocturnal recordings. The number of recordings required to reach an asymptote for detectability was between 81 and 97, depending on recording length. We provide objective-specific recommendations for Eastern Whip-poor-will surveys and suggest unconstrained passive acoustic monitoring as the preferred survey method for many objectives. Given the rise of passive acoustic monitoring, survey practices for many species should be revisited because the increases in sampling effort provided by ARUs can improve cumulative detection probability and potentially outweigh the advantages of limiting surveys to times and dates of optimal detectability. sur la détectabilité, la détectabilité maximale se situant à 13 °C et à 4 heures après le coucher du soleil. L'altitude de la lune et le jour de l'année ont eu des effets positifs sur la détectabilité, tandis que la vitesse du vent a eu des effets négatifs sur celle-ci. Nous avons constaté que le fait de restreindre les relevés aux valeurs optimales de ces covariables de détectabilité ne valait la peine que jusqu'à 10 enregistrements, après quoi la probabilité cumulée de détecter un engoulevent à chaque site était égale entre les enregistrements nocturnes restreints ou non restreints. Le nombre d'enregistrements requis pour atteindre une asymptote de détectabilité se situait entre 81 et 97, selon la longueur de l'enregistrement. Nous offrons des recommandations spécifiques aux objectifs pour les inventaires d'Engoulevent bois-pourri et propo","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70961193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Canada Goose populations harvested in Eastern James Bay by Eeyou Istchee Cree hunters","authors":"J. Giroux, J. Rodrigue, R. W. Brook, M. Patenaude-Monette","doi":"10.5751/ace-02059-170105","DOIUrl":"https://doi.org/10.5751/ace-02059-170105","url":null,"abstract":"Canada Geese (Branta canadensis) are an important wildlife food resource for Cree people living in communities along the James Bay coasts. According to Traditional Ecological Knowledge, environmental changes along the coast have affected hunting success. Also, changes in the relative abundance of different goose populations that use James Bay may affect hunting opportunities. The objective of our study was to use band recoveries to identify Canada Goose populations harvested by Eeyou Istchee Cree hunters in their Eastern James Bay territory between 2000 and 2020. A total of 744 band recoveries were reported including 198 from the Atlantic Population (AP), 82 from the Southern Hudson Bay Population (SHBP), 122 from the Atlantic Flyway Resident Population (AFRP), 339 from the Mississippi Flyway Giant Population (MFGP), and three that could not be assigned to a population. The percentage of banded geese that were recovered was three times greater for the AP than for the other three populations. Eighty-seven percent of recoveries were reported in spring and 72% were submitted by hunters from the two northern communities (Chisasibi and Wemindji). Most recoveries were reported from coastal hunting sites, but a greater proportion of banded geese of the AP were recovered inland compared to the other goose populations, an indication of their propensity to migrate inland. The most noticeable change in the goose harvest compared to the 1970s was the rapid increase of molt migrant temperate-breeding geese of the AFRP and MFGP. In addition to environmental changes along the James Bay east coast, changes in the relative abundance of each goose population may affect hunting success because each population is differently susceptible to hunting within the territory due to differences in migratory behavior. Our study demonstrates the usefulness of band recoveries in tracking these changes and we therefore encourage agencies to maintain banding programs and Cree hunters to report their recovered bands. Populations de Bernaches du Canada récoltées par les chasseurs Cris d'Eeyou Istchee dans l'est de la Baie James RÉSUMÉ. Les Bernaches du Canada (Branta canadensis) sont une ressource alimentaire importante pour les populations Cris vivant le long des côtes de la Baie James. Selon les connaissances écologiques traditionnelles, les changements environnementaux côtiers ont influencé le succès de chasse. Les changements dans l'abondance relative des différentes populations de bernaches qui utilisent la Baie James peuvent aussi avoir affecté les opportunités de chasse. L'objectif de notre étude était d'utiliser les retours de bagues pour identifier les populations de Bernaches du Canada récoltées par les chasseurs Cris d'Eeyou Istchee dans le territoire est de la Baie James entre 2000 et 2020. Un total de 744 retours de bagues a été rapporté incluant 198 de la population de l'Atlantique (AP), 82 de la population du sud de la Baie d'Hudson (SHBP), 122 de la population rési","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70961332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Losing the edge: trends in core versus peripheral populations in a declining migratory songbird","authors":"Rémi Torrenta, K. Hobson, Douglas C. Tozer, M. Villard","doi":"10.5751/ace-02146-170128","DOIUrl":"https://doi.org/10.5751/ace-02146-170128","url":null,"abstract":",","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pre-breeding foraging ecology of three tern species nesting in the Gulf of Maine","authors":"Rachel Bratton, Henry D. Legett, Paula Shannon, Keenan Yakola, A. Gerson, M. Staudinger","doi":"10.5751/ace-02112-170119","DOIUrl":"https://doi.org/10.5751/ace-02112-170119","url":null,"abstract":"A variety of seabird species migrate annually from wintering grounds in the Southern Hemisphere to the Gulf of Maine, USA to breed and raise their young. Post-migration, adult seabirds depend on the spatio-temporal match of reliable food resources to replenish energy reserves before breeding. However, the conditions during this critical window of time are becoming increasingly uncertain given the magnitude and pace at which climate change is impacting the Gulf of Maine region. We investigated the prebreeding foraging ecology of Arctic Terns (Sterna paradisaea), Common Terns (S. hirundo), and the federally endangered Roseate Tern (S. dougallii) by analyzing stable carbon (δC) and nitrogen (δN) isotopes in eggshell tissues collected from seven islands in the Gulf of Maine from 2016 to 2018. Results show at the interspecific level, adult foraging patterns are consistent with expectations based on chick diets. At interisland and interannual scales, variation in isotopic values and niche breadths suggest foraging habits are highly localized. Although uncertainty remains, interannual trends also suggest warmer ocean conditions are either affecting tern foraging behaviors and/or prey resource availability during the late spring and early summer. Overall, results provide new information on adult tern foraging ecology in an important breeding area experiencing rapid environmental change. Écologie de l'alimentation avant la reproduction de trois espèces de sternes nichant dans le golfe du Maine RÉSUMÉ. Diverses espèces d'oiseaux marins migrent chaque année des aires d'hivernage dans l'hémisphère Sud vers le golfe du Maine, aux États-Unis, pour s'y reproduire et élever leurs oisillons. Après la migration, les oiseaux marins adultes dépendent de la présence spatio-temporelle de ressources alimentaires fiables pour reconstituer leurs réserves énergétiques avant la nidification. Cependant, les conditions durant cette fenêtre critique deviennent de plus en plus incertaines étant donné l'ampleur et le rythme auxquels les changements climatiques affectent la région du golfe du Maine. Nous avons étudié l'écologie de l'alimentation avant la reproduction des Sternes arctique (Sterna paradisaea), pierregarin (S. hirundo) et de Dougall (S. dougallii) cette dernière étant une espèce menacée au niveau fédéral -, en analysant les isotopes stables du carbone (δ13C) et de l'azote (δ15N) dans les tissus de coquilles d'oeufs collectées sur sept îles du golfe du Maine de 2016 à 2018. À l'échelle interspécifique, les tendances de la recherche de nourriture par les adultes sont conformes aux attentes basées sur le régime alimentaire des poussins. Aux échelles inter-îles et interannuelles, la variation des valeurs isotopiques et de l'étendue des niches indiquent que les habitudes de recherche de nourriture sont très localisées. Bien que des incertitudes demeurent, les tendances interannuelles portent également à croire que les conditions océaniques plus chaudes affectent les com","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigating avian collisions with power lines through illumination with ultraviolet light","authors":"David M. Baasch, Amanda M. Hegg, J. F. Dwyer, Andrew J. Caven, William E. Taddicken, C. Worley, Amanda H. Medaries, Cody G. Wagner, Phoebe G. Dunbar, Nicole D. Mittman","doi":"10.5751/ace-02217-170209","DOIUrl":"https://doi.org/10.5751/ace-02217-170209","url":null,"abstract":". Collisions with anthropogenic structures by long-distance migrants and threatened and endangered species are a growing global conservation concern. Increasing the visibility of these structures may reduce collisions but may only be accepted by local residents if it does not create a visual disturbance. Recent research has shown the potential for ultraviolet (UV) light, which is nearly imperceptible to humans, to mitigate avian collisions with anthropogenic structures. We tested the effectiveness of two UV (390–400 nm) Avian Collision Avoidance Systems (ACASs) at reducing collisions at two 260-m spans of marked power lines at the Iain Nicolson Audubon Center at Rowe Sanctuary, an important migratory bird stopover location in Nebraska. We used a randomized design and a tiered model selection approach employing generalized linear models and the Akaike Information Criterion to assess the effectiveness of ACASs considering environmental (e.g., precipitation) and detection probability (e.g., migration chronology) variables. We found focal (assessed power line) and distal (neighboring power line) ACAS status and environmental variables were important predictors of avian collisions. Our top model suggests that the focal ACAS illumination reduced collisions by 88%, collisions were more likely at moderate (10–16 km/h) compared to lower or higher wind speeds, and collision frequency decreased with precipitation occurrence. Our top model also indicates that the distal ACAS illumination reduced collisions by 39.4% at the focal power line when that ACAS was off, suggesting a positive “neighbor effect” of power line illumination. Although future applications of ACASs would benefit from additional study to check for potential negative effects (for example, collisions involving nocturnal foragers such as bats or caprimulgiform birds drawn to insects), we suggest that illuminating power lines, guy wires, towers, wind turbines, and other anthropogenic structures with UV illumination will likely lower collision risks for birds while increasing human acceptance of mitigation measures in urban areas. approche de sélection de modèle à plusieurs niveaux employant des modèles linéaires généralisés et le critère d'information Akaike pour évaluer l’efficacité des ACAS en tenant compte des variables environnementales (par ex. précipitations) et de probabilité de détection (par ex. chronologie des migrations). Nous avons constaté que les variables de statut ACAS et d’environnement focales (ligne électrique évaluée) et distales (ligne électrique voisine) permettaient de prédire assez précisément les collisions aviaires. Notre principal modèle suggère que l’illumination ACAS focale réduit les collisions de 88 %, que les collisions se font plus probablement à une vitesse de vent modérée (10 à 16 km/h) plutôt qu’à des vitesses de vent plus faibles ou plus fortes, et que la fréquence des collisions diminue en cas de précipitations. Notre principal modèle indique que l’illuminat","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioacoustically derived migration arrival times in boreal birds: implications for assessing habitat quality","authors":"John J. Johnson, E. Bayne","doi":"10.5751/ace-02224-170213","DOIUrl":"https://doi.org/10.5751/ace-02224-170213","url":null,"abstract":". Long-distance migrant songbirds are declining globally. Reversing declines requires a good understanding of habitat quality. Local studies have shown that territory settlement date (arrival) is generally correlated with density and productivity. Despite widespread acceptance, large-scale multispecies demonstrations of arrival time being correlated with habitat quality are lacking. We investigated whether arrival date estimated from ecozonal scale bioacoustic monitoring could be predicted by an independent estimate of estimated density for Ovenbird ( Seiurus aurocapilla ), Tennessee Warbler ( Leiothlypis peregrina ), and Yellow-rumped Warbler ( Setophaga coronata ). We also examined local Ovenbird settlement patterns by comparing relative arrival and observed local density differences between nearby territories. Arrival date was estimated as the first focal species detection date on a breeding territory and the cure4insect R package was used to predict estimated average density. Using predicted average density as a habitat quality proxy, we found earlier arrivals in higher quality territories (Ovenbird 1.04 +/- 0.33 days earlier, Tennessee Warbler 1.96 +/- 0.36 days earlier, Yellow-rumped Warbler 1.23 +/- 0.54 days earlier). We also showed that arrival time was earlier in habitats preferred by each species. Spatial patterns of arrival varied among species although latitude was always an important predictor. Locations where predicted Ovenbird densities were estimated to be higher were filled before sites with lower predicted density but only 600 m away (2.9 +/- 1.4 days earlier). Correlating migrant arrival time and density suggests density is a reasonable measure of habitat quality. Combined, density and arrival data from bioacoustics provide a habitat-assessment tool that better informs the types of that of and RÉSUMÉ. Les populations de passereaux migrateurs de longues distances sont en déclin dans le monde entier. Pour inverser cette tendance, il est indispensable de bien comprendre la qualité de l’habitat. Des études locales indiquent que la date d'implantation sur le territoire (d’arrivée) est généralement liée à la densité et à la productivité. Bien que cette idée soit largement acceptée, nous manquons de preuves concernant le lien entre la date d’arrivée en masse d’espèces multiples et la qualité de l’habitat. Nous avons cherché à savoir si la date d’arrivée estimée n fonction d'une surveillance bioacoustique à l’échelle des écozones pouvait être prévue par une estimation indépendante de la densité chez la paruline couronnée ( Seiurus aurocapilla ), la paruline obscure ( Leiothlypis peregrina ) et la paruline à croupion jaune ( Setophaga coronata ). Nous avons également examiné les modèles d'implantation des parulines couronnées en comparant la date d’arrivée relative et observé les différences de densité locales entre les territoires voisins. La date d’arrivée a été estimée comme la première date de détection de l’espèce focale sur un te","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population density estimates and key microhabitat parameters for two endangered tropical forest understory insectivorous passerines from the Pernambuco Endemism Center","authors":"Luiza Carvalho Prado, T. C. Dias, Lahert William Lobo de Araújo, L. F. Silveira, M. Francisco","doi":"10.5751/ace-02231-170222","DOIUrl":"https://doi.org/10.5751/ace-02231-170222","url":null,"abstract":". The Pernambuco Endemism Center (PEC) is the most fragmented and degraded tract of the Atlantic Forest, considered to be a hotspot within a hotspot. Recent bird extinctions and the high number of endangered taxa have called the attention of conservation practitioners all over the world to this area. Among the most vulnerable groups of birds are the insectivorous passerines of the forest understory, yet empirical information on demography and habitat requirements are unavailable for these taxa. Here, we provide population density estimates and microhabitat selection information for two endangered insectivorous passerines endemic to the PEC, the Pernambuco Fire-eye, Pyriglena pernambucensis , and the Black-cheeked Gnateater, Conopophaga melanops nigrifrons . Distance-sampling estimates resulted in population densities of 0.15 and 0.35 individuals/ha, respectively, in an Atlantic Forest fragment of approximately 1000 ha. Extrapolations of population densities to 39 fragments where the occurrence of these taxa was confirmed resulted in population estimates of 4936 individuals for the Pernambuco Fire-eye and 12,679 individuals for the Black-cheeked Gnateater, but these may be underestimates because other fragments where they could potentially occur were never surveyed. Although extrapolating data from only one fragment to other areas is problematic, these are the first rough minimum population size estimates for birds from the PEC. Microhabitat preference analyses revealed that both species selected sites with denser forest understory vegetation, which is associated with areas in regeneration. This is evidence that these taxa can tolerate certain levels of habitat disturbance and that their limited distributions and habitat loss may be more important causes of threat than habitat requirements. In the face of ongoing PEC fragmentation, our data will serve to parameterize other studies and may contribute to practical conservation policies","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Habitat selection and site fidelity on winter home ranges of Eastern Whip-poor-wills (Antrostomus vociferus)","authors":"M. Bakermans, Joshua M. Driscoll, A. Vitz","doi":"10.5751/ace-02237-170217","DOIUrl":"https://doi.org/10.5751/ace-02237-170217","url":null,"abstract":"","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In the twilight zone: patterns in Common Nighthawk (Chordeiles minor) acoustic signals during the breeding season and recommendations for surveys","authors":"Kevin C. Hannah, L. Leston, Elly C. Knight, R. Weeber","doi":"10.5751/ace-02241-170218","DOIUrl":"https://doi.org/10.5751/ace-02241-170218","url":null,"abstract":". Surveys optimized to coincide with peak detectability of target species are critical to the success of monitoring programs, especially those targeting species of conservation concern. Established species-specific survey protocols are often inconsistent between jurisdictions, with limited spatial and temporal data to inform survey timing. The recent proliferation of programmable autonomous recording units (ARUs) and automated detection software enables the processing of huge volumes of acoustic data, which can improve our understanding of the acoustic phenology of many bird species. In May–July 2014, we deployed ARUs across a gradient of latitude near the northern limit of the breeding range of the Common Nighthawk ( Chordeiles minor ), a species of conservation concern, to quantify variation in temporal detection patterns. Most activity occurred after sunset and before sunrise, with a pronounced peak during civil twilight. We found considerable latitudinal differences in the activity patterns of birds, related to variation in the occurrence or duration of twilight periods. At northern sites (> 60° N), birds were active from dusk until dawn, likely because civil twilight lasted the entire period. At southern sites (< 55° N), twilight periods were short, resulting in concentrated, bimodal activity. Activity peaked in the middle of the breeding season, which occurred earlier in the south than the north. Our results suggest surveys should occur in June in southern Canada (> 50° N) and between mid-June and mid-July further north, given high activity rates throughout the breeding season. Given that non-vocal booms are more strongly associated with breeding activity and nesting sites, future surveys should focus on targeting this acoustic signal. Considering the timing of activity patterns in this species, we recommend a targeted, species-specific survey to ensure documentation of their abundance and distribution. Finally, we provide recommendations to improve survey timing and provide advice for acoustic data management and processing in relation to this species. pic prononcé pendant le crépuscule civil. Nous avons trouvé des différences latitudinales considérables dans la tendance de l’activité des oiseaux, liées à la variation de l’occurrence ou de la durée des périodes crépusculaires. Sur les sites septentrionaux (> 60° N.), les oiseaux étaient actifs du crépuscule à l’aube, probablement parce que le crépuscule civil durait toute la période. Sur les sites méridionaux (< 55° N.), les périodes crépusculaires étaient courtes, ce qui a entraîné une activité concentrée et bimodale. L’activité a atteint un pic au milieu de la saison de nidification, qui a eu lieu plus tôt dans le sud que dans le nord. Nos résultats indiquent que les relevés devraient s’effectuer en juin dans le sud du Canada (> 50° N.) et entre la mi-juin et la mi-juillet plus au nord, étant donné le taux d’activité élevé tout au long de la saison de nidification. Comme les booms non vo","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"26 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Snag density and stand age, but not stand size, explain occupancy and reproduction of an imperiled cavity nester in early successional forest","authors":"Meghan A. Beatty, K. Miller, Robert J. Fletcher Jr","doi":"10.5751/ace-02261-170236","DOIUrl":"https://doi.org/10.5751/ace-02261-170236","url":null,"abstract":"","PeriodicalId":49233,"journal":{"name":"Avian Conservation and Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70962956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}