Photo by Sue Anderson

Bald Eagles –

We surveyed the breeding population of bald eagles (Haliaeetus leucocephalus) in Oregon and along the lower Columbia River from 1978–2007. Surveys were conducted annually by aircraft, boat, and/or afoot from 1 February–31 August to determine occupancy and productivity of breeding areas. We divided the study area into ten watersheds based on Recovery Plan management zones. Overall, the minimum size of the breeding population increased from 66 occupied breeding areas in 1978 (65 in Oregon and 1 in Washington) to 553 in 2007 (496 in Oregon and 57 in Washington). Population growth rate (r) was exponential for all areas combined, but varied among the nine watersheds from 0.048 for the Deschutes to 0.147 for the Willamette. The average increase in the breeding population was 0.073 or a 7.3% increase per year for the study area. At the beginning of the study, the breeding population was located primarily in the Deschutes, Klamath, Pacific, and Columbia watersheds with dispersed breeding areas elsewhere. By the end of the study, the population was concentrated in those four areas plus the Willamette, Rogue, and Umpqua watersheds, and additional breeding areas were dispersed throughout most of the state except for the Owyhee watershed of southeast Oregon. We documented breeding phenology over the 30-year period and discovered an approximately five-day advance in the egg-laying period for breeding areas west of the Cascades, which may have been a result of warmer late-winter and spring temperatures in the region during the latter part of the study. Read the entire report here :

Golden Eagles

Photo by Charlie Baughman

GOLDEN EAGLES (Aquila chrysaetos) NESTING IN OREGON, 2011– 2018: Annual Report

The golden eagle (Aquila chrysaetos) is found throughout the Northern Hemisphere. In North America, it occurs from the arctic to central Mexico and is one of the largest North American raptors. In Oregon, golden eagles occur statewide and are most common in the eastern half of the state. Migrant golden eagles from other areas visit the state in the winter, while nesting pairs mostly appear to be year-round residents. Golden eagles take five years to attain full-adult plumage and can breed prior to that. Subadult golden eagles can stay close to their natal areas as they mature or may travel great distances from where they were hatched, or both. Non-breeding golden eagles from Oregon may visit surrounding states, and those from surrounding states may spend time in Oregon. There were no statewide research projects on golden eagles nesting in Oregon until this study. The project was initiated in 2011 because of concerns about the effects of energy development on the species. The goal of this work is to find as many golden eagle nests in the state as possible each nesting season (February through July) to document nest use and determine how many eaglets are raised each year. Over 60 organizations and 700 individuals, including citizen science volunteers have contributed to the project. Through 2018, 1,018 golden eagle nesting areas have been identified, 577 were reported before 2011, and 441 have been added since. Each year ~77% of nesting areas were observed; ~58% of the observed nesting areas were occupied; nesting outcome was determined at ~87% of occupied nesting areas; and ~59% of those with known outcome were successful. As a result of that effort, a total of 2,246 golden eaglets were counted from 2011–2018 in Oregon. The minimum golden eagle nesting population for Oregon was estimated at ~589 nesting pairs; and the minimum number of eaglets produced each year was estimated at ~486. 2019 will be the ninth consecutive year of what we hope will be a ten-year project that will end after the 2020 nesting season and provide a valuable description of the status of nesting golden eagles in Oregon at the beginning of the 21st century. Read the 2018 entire report here :