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

Abstract

ABSTRACT. 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.Recensement de Hiboux des marais (Asio flammeus) dans la région Intramontagnarde Ouest nordaméricaine : utilisation de la participation citoyenne pour effectuer un suivi à grande échelle RÉSUMÉ. Le Hibou des marais (Asio flammeus), espèce de milieux ouverts nichant dans le nord des États-Unis et au Canada, a vraisemblablement subi une baisse importante de longue date et à grande échelle. Toutefois, la cause et la magnitude de cette baisse ne sont pas bien comprises. Nous avons choisi d'étudier les deux premières de six priorités de conservation proposées antérieurement pour cette espèce : 1) mieux établir l'utilisation de l'habitat; et 2) améliorer le suivi de la population. Nous avons recruté 131 bénévoles pour inventorier plus de 6,2 millions d'ha dans l'État de l'Idaho durant la saison de nidification 2015 du Hibou des marais. Nous avons inventorié 75 transects, dont 71 à deux reprises, et avons détecté le Hibou des marais dans 27...

Temporal and spatial population dynamics of the nomadic short‐eared owl across the western United States

“…We provided participants with 2 3-week survey windows, depending upon latitude and elevation, during our March through May survey season in which to perform each survey. We selected the survey windows for each grid cell to best account for the expected period of short-eared owl courtship flight behavior, a time of maximum detectability (Larson and Holt 2016;Miller et al 2016Miller et al , 2022. Although participants could choose any day within the survey windows to perform each survey, we requested that the 2 visits be ≥1 week apart if possible.…”

Accounting for imperfect detection in data from museums and herbaria when modeling species distributions: combining and contrasting data‐level versus model‐level bias correction

“…Occupancy models have been increasingly used to analyze data from citizen‐science projects, which often document aspects of search effort (e.g. number of observers, time spent searching) or ask that volunteers attempt to report all species of a known taxon within defined sampling units (Bled et al 2013, Van Strien et al 2013, Berberich et al 2016, Miller et al 2016, Louvrier et al 2018). An ever‐increasing wealth of opportunistic data arising from digital citizen‐science portals (e.g eBird, naturGucker, iNaturalist) has required careful consideration of how this unstructured data can be translated into a format that is appropriate for the occupancy modeling framework.…”

Golden Eagle Abundance in Alaska: Migration Counts and Movement Data Generate a Conservative Population Estimate

“…Abundance can be relatively straightforward to estimate for sessile organisms occurring within a restricted range (Dzul et al 2013); however, estimating abundance of mobile organisms with wide geographic distributions is more difficult (Whitehead 2002, Dennhardt et al 2015. Geographically broad sampling strategies designed to estimate abundance over large areas can be expensive (Millsap et al 2013, Nielson et al 2014, require large numbers of people (Miller et al 2016), and can be logistically difficult or near impossible to implement across remote landscapes (Dunn et al 2005). These factors have collectively limited researchers from rigorously estimating densities and population sizes of many wildlife species in Alaska (Alaska Department of Fish and Game [ADFG] 2015), including the Golden Eagle (Aquila chrysaetos).…”