Cameras Show Sciurids Visiting White-Headed Woodpecker Nests Without Depredating Contents

Lorenz, Teresa J.; Fischer, Philip C.

doi:10.3996/052017-jfwm-039

Cited by 2 publications

(1 citation statement)

References 24 publications

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“…We found that daily nest survival increased as nest height increased. In our study area, Gray Flycatchers face a diverse assemblage of possible nest predators, including Steller's Jays ( Cyanocitta stelleri ), Clark's Nutcrackers ( Nucifraga columbiana ), Common Ravens ( Corvus corax ), Cooper's Hawks ( Accipiter cooperi ), American Kestrels ( Falco sparverius ), Northern Saw‐whet Owls ( Aegolius acadicus ), golden‐mantled ground squirrels ( Callospermophilus lateralis ), Douglas squirrels ( Tamiasciurus douglasii ), yellow‐pine chipmunks ( Tamias amoenus ), long‐tailed weasels ( Mustela frenata ), deer mice ( Peromyscus maniculatus ), gopher snakes ( Pituophis catenifer ), and striped whip snakes ( Masticophis taeniatus ) (Eichholz and Koenig , Sieving and Willson , Tomback , Boarman and Heinrich , Liebezeit and George , Pietz and Granfors , Richardson and Vander Wall , Kroll and Haufler , Lorenz and Fischer ). Almost half of these potential predators are primarily terrestrial (e.g., gopher snakes and long‐tailed weasels) and venture into trees primarily to forage.…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal factors associated with nest survival of Gray Flycatchers in managed ponderosa pine forests

2019

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Gray Flycatchers (Empidonax wrightii) breed in a variety of habitats in the arid and semi‐arid regions of the western United States, but little is known about their breeding biology, especially in the northern portion of their range where they nest in ponderosa pine (Pinus ponderosa) forests. From May to July 2014 and 2015, we conducted surveys for singing male Gray Flycatchers along the eastern slope of the Cascade Range in Washington, U.S.A, monitored flycatcher nests, and quantified nest‐site vegetation. We used a logistic‐exposure model fit within a Bayesian framework to model the daily survival probability of flycatcher nests. During the 2 yr of our study, we monitored 141 nests, with 93% in ponderosa pines. Mean clutch size was 3.6 eggs and the mean number of young fledged per nest was 3.2. Predation accounted for 90% of failed nests. We found a positive association between daily nest survival and both nest height and distance of nest substrates from the nearest tree. Flycatchers that locate their nests higher above the ground and further from adjacent trees may be choosing the safest alternative because higher nests may be less exposed to terrestrial predators and nests in trees that are farther from other trees may be less exposed to arboreal predators such as jays (Corvidae) that may forage in patches with connected canopies. Nests in trees farther from other trees may also allow earlier detection of approaching predators and thus aid in nest defense.

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Section: Discussionmentioning

confidence: 99%

Spatial and temporal factors associated with nest survival of Gray Flycatchers in managed ponderosa pine forests

2019

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Efficacy of automated detection of motion in wildlife monitoring videos

et al. 2019

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Documenting biodiversity and wildlife behavior is time‐consuming and potentially invasive. Remotely placed cameras often are used to increase sampling and minimize disturbance of focal animals. Such wildlife monitoring programs can entail numerous and lengthy videos requiring massive amounts of time to analyze their content. We evaluated the efficacy of a computer program, MotionMeerkat (http://benweinstein.weebly.com/motionmeerkat.html), for automated detection of motion in 21 continuous, 3‐hour‐long videos monitoring woodpecker (Picidae) nest cavities during 2016 in Washington, USA. The program produces still‐image frame captures from the video where motion was detected, files logging the video time‐stamps of each frame, and x,y coordinates within each frame where motion was detected. We compared program results with video reviews conducted by students using a standard protocol for identifying movement events and species identification. The program tagged 60% more motion events of all types, and 38% more motion events of target species (woodpeckers and potential predators), than were found by student reviews. We also conducted sensitivity analyses of the program by varying program input settings; results suggest that optimal settings depend on the video quality, environmental conditions, desired target species, and type of motion. We conclude that automated motion‐detection programs such as MotionMeerkat can play important roles in use of continuous videos for wildlife monitoring, but results need to be reviewed by the researcher. © 2019 The Wildlife Society.

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Cameras Show Sciurids Visiting White-Headed Woodpecker Nests Without Depredating Contents

Cited by 2 publications

References 24 publications

Spatial and temporal factors associated with nest survival of Gray Flycatchers in managed ponderosa pine forests

Spatial and temporal factors associated with nest survival of Gray Flycatchers in managed ponderosa pine forests

Efficacy of automated detection of motion in wildlife monitoring videos

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