Dataset for Golden Eagle Dietary Shifts Following Wildfire and Shrub Loss Have Negative Consequences for Nestling Survivorship

• Main Authors: Heath, Julie A., Kochert, Mike, Steenhof, Karen
• Format: Text
• Language: unknown
• Published: ScholarWorks 2021
• Subjects: Aquila chrysaetos; Black-tailed Jackrabbit; climate change; diet; predator; prey; Rock Pigeon; shrub; trichomonosis; golden eagle
• Online Access: https://scholarworks.boisestate.edu/bio_data/8; https://doi.org/10.18122/bio_data.8.boisestate; https://scholarworks.boisestate.edu/context/bio_data/article/1007/type/native/viewcontent/bio_data_8_heath_06072021.zip

Wildfires and invasive species have caused widespread changes in western North America's shrub-steppe landscapes. The bottom-up consequences of degraded shrublands on predator ecology and demography remain poorly understood. We used a before-after paired design to study whether Golden Eagle (Aquila chrysaetos) diet and nestling survivorship changed following wildfires in southwestern Idaho, USA. We assessed burn extents from 1981 – 2013 and vegetation changes between 1979 (pre-burn) and 2014 (post-burn) within 3 km of Golden Eagle nesting centroids. We measured the frequency and biomass of individual prey, calculated diet diversity indexes, and monitored nestling survivorship at 15 territories in 1971 – 1981 and 2014 – 2015. On average, 0.70 of the area within 3 km of nesting centroids burned between 1981 – 2013, and the mean proportion of unburned shrubland decreased from 0.73 in 1979 to 0.22 in 2014. Diets in post-burn years were more diverse and had a lower proportion of some shrub-associated species, like Black-tailed Jackrabbits (Lepus californicus) and Mountain Cottontails (Sylvilagus nuttallii), and a higher proportion of American Coots (Fulica americana), Mallards (Anas platyrhynchos), Piute Ground Squirrels (Urocitellus mollis), and Rock Pigeons (Columba livia) compared to pre-burn years. A high proportion of waterfowl represented a novel change in Golden Eagle diets, which are typically dominated by mammalian prey. Nestling survivorship was positively associated with the proportion of Black-tailed Jackrabbits and negatively associated with the proportion of Rock Pigeons in eagle diets. Rock Pigeons are a vector for Trichomonas gallinae, a disease-causing protozoan lethal to young eagles. Nesting attempts were more likely to fail (all young die) in the post-burn period compared to the pre-burn period. Dietary shifts are a common mechanism for predators to cope with landscape change, but shifts away from preferred prey to disease vectors affect nestling survivorship and could lead to population-level ...