Nest Boxes Facilitate Local-Scale Conservation of Common Goldeneye (Bucephala clangula) and Bufflehead (Bucephala albeola) in Alberta, Canada

We tested the general predictions of increased use of nest boxes and positive trends in local populations of Common Goldeneye (Bucephala clangula) and Bufflehead (Bucephala albeola) following the large-scale provision of nest boxes in a study area of central Alberta over a 16-year period. Nest boxes were rapidly occupied, primarily by Common Goldeneye and Bufflehead, but also by European Starling (Sturnus vulgaris). After 5 years of deployment, occupancy of large boxes by Common Goldeneye was 82% to 90% and occupancy of small boxes by Bufflehead was 37% to 58%. Based on a single-stage cluster design, experimental closure of nest boxes resulted in significant reductions in numbers of broods and brood sizes produced by Common Goldeneye and Bufflehead. Occurrence and densities of Common Goldeneye and Bufflehead increased significantly across years following nest box deployment at the local scale, but not at the larger regional scale. Provision of nest boxes may represent a viable strategy for increasing breeding populations of these two waterfowl species on landscapes where large trees and natural cavities are uncommon but wetland density is high.

Short-eared Owl (Asio flammeus) surveys in the North American Intermountain West: utilizing citizen scientists to conduct monitoring across a broad geographic scale

The Short-eared Owl (Asio flammeus) is an open-country species breeding in the northern United States and Canada, and has likely experienced a long-term, range-wide, and substantial decline. However, the cause and magnitude of the decline is not well understood. We set forth to address the first two of six previously proposed conservation priorities to be addressed for this species: (1) better define habitat use and (2) improve population monitoring. We recruited 131 volunteers to survey over 6.2 million ha within the state of Idaho for Short-eared Owls during the 2015 breeding season. We surveyed 75 transects, 71 of which were surveyed twice, and detected Short-eared Owls on 27 transects. We performed multiscale occupancy modeling to identify habitat associations, and performed multiscale abundance modeling to generate a state-wide population estimate. Our results suggest that within the state of Idaho, Short-eared Owls are more often found in areas with marshland or riparian habitat or areas with greater amounts of sagebrush habitat at the 1750 ha transect scale. At the 50 ha point scale, Short-eared Owls tend to associate positively with fallow and bare dirt agricultural land and negatively with grassland. Cropland was not chosen at the broader transect scale suggesting that Short-eared Owls may prefer more heterogeneous landscapes. On the surface our results may seem contradictory to the presumed land use by a “grassland” species; however, the grasslands of the Intermountain West, consisting largely of invasive cheatgrass (Bromus tectorum), lack the complex structure shown to be preferred by these owls. We suggest the local adaptation to agriculture represents the next best habitat to their historical native habitat preferences. Regardless, we have confirmed regional differences that should be considered in conservation planning for this species. Last, our results demonstrate the feasibility, efficiency, and effectiveness of utilizing public participation in scientific research to achieve a robust sampling methodology across the broad geography of the Intermountain West.