![]() ![]() 668–668c) and the Migratory Bird Treaty Act (16 U.S.C. Golden Eagles ( Aquila chrysaetos) are a federally protected species under the Bald and Golden Eagle Protection Act (16 U.S.C. Further, for diet research, understanding the accuracy of cameras relative to historical methods is important for comparing results across studies that use different methods. However, fixed camera installation creates a persistent change in the nest environment that may disturb nesting birds, so best practices for camera installation and use are necessary. Technological advances have decreased the cost and improved the portability of video and motion-activated still cameras, making them an excellent option for remote monitoring via fixed installation at the nest or unmanned aerial vehicles. This approach requires fewer visits to a nest but, in the past, the use of cameras in the field was limited because of the equipment expense and labor (e.g., repeated changing of heavy power sources). 2015), falcons ( Booms and Fuller 2003, Robinson et al. 2002, López-López and Urios 2010, Longshore et al. Alternatively, remotely controlled or motion-activated cameras, or video-recording equipment, have been used to study diets of eagles ( Dykstra et al. Other researchers have used a spotting scope or telephoto lens to take images of prey deliveries from a distance, but this method requires an observer to be present, and therefore is labor intensive ( Jenkins 1978, Korňan and Macek 2011, Shafaeipour 2015a). This approach requires repeated visits and may be biased towards large prey that have inedible parts (e.g., feathers Marti et al. One commonly used method to study raptor diets is inspection of pellets and prey remains collected at the nest ( Simmons et al. Cost-efficient methods that decrease researcher disturbance and accurately record bird behavior and nest contents are necessary for collecting valuable information on the ecology of cliff-nesting raptors. 2004, Arroyo and Razin 2006, González et al. Repeated human visits may disturb adults leading to decreased nest attendance ( Spaul and Heath 2017) or have negative effects on nesting success ( Brambilla et al. ![]() Unfortunately, observation of nest contents and bird behavior in cliff nests can be challenging because it is often difficult to see into the nest without being in close proximity or directly accessing the nest. Information on raptor diet, delivery of prey to young, and productivity are important for understanding basic ecological relationships and assessing possible threats to successful reproduction. Camera appearance should be minimized, and post-installation monitoring that allows for timely responses to nest-avoidance behavior by adult eagles is important to prevent adverse effects on nesting success. However, cameras should be used judiciously because installation creates a persistent manipulation at the nest. ![]() Trail cameras may be a reliable and cost-effective option to address clearly defined research goals and obtain required information about eagle behavior and nest contents. Cameras recorded productivity, fledging dates, and in one case, a nestling death. 316), were more likely to detect the smallest and largest prey, and cost half as much. Compared to inspection of prey remains and pellets, cameras recorded twice the number of prey (622 vs. We visited the 10 remaining nests every 4 d to collect prey remains and pellets to generate prey-specific detection estimates for both images, and prey remains and pellets. At two nests, adult eagles did not return to nests or exhibited behaviors suggesting avoidance of the cameras, but returned to the nests after cameras were removed. Following installation, we monitored adult behavior using direct observation and post-installation image review. In 20, we installed cameras at 12 Golden Eagle nests with 18–42-d-old nestlings. Our goals were to develop a protocol for installing motion-activated trail cameras at Golden Eagle ( Aquila chrysaetos) nests to record diet information and productivity, and to estimate prey detection probability using different diet study methods. Studies of cliff-nesting raptors can be challenging because direct observations of nest contents are difficult.
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