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Feather corticosterone reveals developmental challenges in a long-term study of juvenile northern spotted owls

October 12, 2021
  1. Corticosterone is a steroid hormone integral to a variety of physiological pathways and is strongly associated with the vertebrate stress response. In avian species, circulating corticosterone is sequestered into developing feathers and is used as an indicator of energy allocation during feather growth and widely applied in conservation physiology.
  2. The northern spotted owl Strix occidentalis caurina is a federally threatened old-growth forest obligate of conservation concern endemic to the Pacific Northwest of the United States and Canada. The effects of landscape characteristics and individual variation on early development in spotted owls remain unstudied despite long recognition of this knowledge gap and its potential importance to species conservation.
  3. We quantified corticosterone concentrations in 4,720 feathers from 1,056 juvenile spotted owls across seven study areas between 2001 and 2017. We used an information-theoretic approach to examine the environmental and individual factors related to feather corticosterone in juvenile spotted owls as an indicator of challenges during early development.
  4. Feather corticosterone was positively related to temperature and precipitation, and negatively related to juvenile mass at banding. We found strong support for an interaction between mass and precipitation, with greater amounts of precipitation being associated with higher levels of feather corticosterone in lighter juveniles. The temperature and precipitation metric with the strongest relationship with feather corticosterone occurred during the fledging period, suggesting that this period presents an energetic challenge for juvenile spotted owls. Greater juvenile mass decreased the effect of precipitation, suggesting that greater mass was important for juveniles to maintain homeostasis during fledgling.
  5. Feather corticosterone in juvenile spotted owls provided insights to the challenges faced during early development, adding to our understanding of spotted owl life history and potential for population recovery.
Publication Year 2022
Title Feather corticosterone reveals developmental challenges in a long-term study of juvenile northern spotted owls
DOI 10.1111/1365-2435.13944
Authors Ashlee J. Mikkelsen, Damon B. Lesmeister, Kathleen M. O'Reilly, Katie Dugger
Publication Type Article
Publication Subtype Journal Article
Series Title Functional Ecology
Index ID 70229722
Record Source USGS Publications Warehouse
USGS Organization Coop Res Unit Seattle