Fink, D., T. Auer, A. Johnston, M. Strimas-Mackey, S. Ligocki, O. Robinson, W. Hochachka, L. Jaromczyk, A. Rodewald, C. Wood, I. Davies, A. Spencer. 2021. eBird Status and Trends, Data Version: 2020; Released: 2021. Cornell Lab of Ornithology, Ithaca, New York. <https://doi.org/10.2173/ebirdst.2021>.
Summary
We used processed eBird relative abundance data from 2020 provided by the Lab of Ornithology, Cornell University (Fink et al, 2021) to develop bald and golden eagle relative abundance maps. eBird relative abundance values are a modeled data product that represent the average number of eagles of each species expected to be seen by an expert eBirder who observes for 1 hour at the optimal time of day for detecting the species, and who travels no more than 1 kilometer during the observation session (see eBird FAQs at ebird.org/spain/science/status-and-trends/faq#mean-relative-abundance). The strength of the relative abundance models is the standardization of approach across the entire contiguous U.S. and the ability to consider environmental [...]
Summary
We used processed eBird relative abundance data from 2020 provided by the Lab of Ornithology, Cornell University (Fink et al, 2021) to develop bald and golden eagle relative abundance maps. eBird relative abundance values are a modeled data product that represent the average number of eagles of each species expected to be seen by an expert eBirder who observes for 1 hour at the optimal time of day for detecting the species, and who travels no more than 1 kilometer during the observation session (see eBird FAQs at ebird.org/spain/science/status-and-trends/faq#mean-relative-abundance). The strength of the relative abundance models is the standardization of approach across the entire contiguous U.S. and the ability to consider environmental covariates, data from neighboring cells, and information from the past in determining the relative abundance value of a particular cell. The dataset we used provided relative abundance estimates for bald and golden eagles throughout the coterminous United States at ~3 km2 resolution for each of four seasonal time-periods (pre-breeding migration, breeding, post-breeding migration, and non-breeding; see below). Using multiple seasons of data provides better measures of relative abundance for mapping purposes (Johnston et al. 2020), and our goal was to identify locations with high relative abundance in any one season.
