ABSTRACT. The impact of anthropogenic activities on breeding bird populations are typically assessed using nest success despite the importance of the postfledging period and juvenile survival for the population dynamics of many birds. Using a combination of radio telemetry data collected between 2012 and 2014, and long-term monitoring data collected between 2005 and 2016, we evaluated whether postfledging survival of Yellow Warblers (Setophaga petechia) is affected when their riparian nesting habitat becomes inundated by the Upper Arrow Lakes Reservoir in the Columbia River Valley near Revelstoke, British Columbia, Canada. Thirty-eight percent of radiotagged fledglings (n = 26) survived for at least 21 days after leaving the nest. Radio-tagged birds that fledged from nests in territories that were inundated by water tended to be have lower survival than those that fledged from nests in territories that were not inundated by water. Local recruitment was low (6.4%, n = 438). Local recruitment was nevertheless positively affected by nestling condition prior to fledging. Fledglings from territories that were not inundated by water also tended to be more likely to recruit locally than those that fledged from territories that were inundated by water. In both cases, we estimated that reservoir operations that flooded habitat reduced postfledging survival or local recruitment by approximately 50%. Our study emphasizes the importance of considering the postfledging period when developing mitigation measures or management plans aimed at minimizing the impact of anthropogenic activities on bird populations. Survie des jeunes après l'envol et recrutement local d'un passereau ripicole nichant dans un habitat touché par la régulation du niveau d'eau d'un réservoirRÉSUMÉ. Les impacts qu'ont les activités anthropiques sur les populations d'oiseaux nicheurs sont habituellement évalués à partir du succès de nidification, malgré l'importance de la période suivant l'envol des jeunes et la survie juvénile dans la dynamique de population de nombreux oiseaux. En combinant des données de radiotélémétrie obtenues entre 2012 et 2014 et des données provenant d'un suivi réalisé de 2005 à 2016, nous avons évalué dans quelle mesure la survie après l'envol des jeunes de Paruline jaune (Setophaga petechia) était affectée lorsque leur habitat de nidification se trouve inondé par le réservoir Upper Arrow Lakes dans la vallée du fleuve Columbia près de Revelstoke, Colombie-Britannique, Canada. Trente-huit pourcent des jeunes munis d'un émetteur (n = 26) ont survécu au moins 21 jours après avoir quitté le nid. La survie des jeunes ayant pris leur envol de nids situés sur des territoires ayant été inondés était généralement plus faible que celle des oiseaux ayant pris leur envol de nids situés sur des territoires n'ayant pas été inondés. Le recrutement local était faible (6,4 %, n = 438). Néanmoins, le recrutement local était positivement lié à la condition des jeunes avant l'envol. Les jeunes ayant pris leur envol dans les territoires non inondés ...
Habitat use of indicator species is used to prioritize management activities. However, habitat use can vary temporally in response to changes in predation risk and foraging rewards. We deployed satellite tags on 20 black oystercatchers ( Haematopus bachmani ) in four regions of British Columbia, Canada, to examine habitat use and selection decisions across seasonal, diel and tidal cycles. We characterized the shoreline in each region and used GLMMs to investigate how habitat characteristics influenced shoreline use by tracked birds. For individuals, we estimated home range size and the frequency key features of the shoreline were re‐visited. Black oystercatchers generally made greater‐than‐expected use of rocky islets and shoreline with freshwater outflows, less tree cover and greater intertidal area. However, while black oystercatchers preferred islets and shoreline with less tree cover at most/all time periods, they only exhibited preferences for greater intertidal area during low tides, and preferences for shoreline with freshwater outflows during the nonbreeding season, day, and high tides. Individual home ranges, on average, contained 46 km of shoreline (range: 12–156 km) and individuals used 10.4 km (range: 6.7–13.9 km). Individuals made greater use of larger islets with less tree cover that were closer to outflows, and greater use of outflows associated with larger streams, greater intertidal areas and gravel substrates. Black oystercatchers' habitat preferences likely reduce predation risk (rocky islets and shoreline with less tree cover) and increase foraging rewards (shoreline with freshwater outflows, greater intertidal area, and gravel substrates). However, habitat preferences appear sensitive to constraints on movement in the breeding season and changes in foraging rewards across the diel and tidal cycle, highlighting the importance of examining habitat use at multiple temporal scales. Black oystercatchers are considered indicators of rocky intertidal health; therefore, critical habitat is expected to be important for a suite of wildlife dependent on safe and productive coastline.
Processing methods that maximize species richness from acoustic recordings obtained from regional monitoring programs can increase detections of uncommon, rare, and cryptic species and provide key information on species status and distribution. Using data from a regional bird monitoring in Yukon, Canada, we (1) compared the number of bird species detected (species richness) and the cost associated with four acoustic processing methods (Listening, Visual Scanning, Recognizer, Recognizer with Validation); and (2) combined Listening and Recognizer with Validation information to increase detections of all bird species at the ecoregion scale. We used comprehensive Visual Scanning to detect all bird species on the recordings. We processed ~1% of the recordings using Listening and detected 56% of the bird community with 71.5 hours of human effort. We used Recognizer (multispecies recognizer BirdNET) with Validation and detected 89% of the bird community with ~22% of the effort required for Visual Scanning (56 and 257 hours respectively). As an application of our approach, we combined Listening and Recognizer with Validation to process recordings from five northern ecoregions and found a 23-63% increase in the number of bird species detected with little additional effort. Combining Listening and Recognizer with Validation can maximize species detections from large passive acoustic monitoring (PAM) datasets.
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