Evidence for Cross-Seasonal Effects: Insights from Long-term Data on Northern Pintail

• Main Author: Zarzycki, Megan C.
• Other Authors: Dugger, Bruce D., Betts, Matthew G., Herlihy, Alan T., Fisheries and Wildlife
• Format: Master Thesis
• Language: English
• Published: Oregon State University
• Subjects: Waterfowl; Cross-seasonal effects; Pacific; Anas acuta
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/tm70n1386

Cross-seasonal effects, where conditions in one season can have consequences in a following season, can have population-level implications for migratory species. To assess the presence of cross-seasonal effects on a migratory dabbling duck population, we examined the relative importance of habitat conditions in multiple seasons on the subsequent productivity of Northern Pintail (Anas acuta) that winter in the Pacific Flyway of North America. Our results indicate that during the period from 1961-2013 habitat conditions during spring staging in Southern Oregon North East California (SONEC) influence the subsequent productivity of pintail, and that the influence of habitat conditions during spring migration was stronger than the relationship between productivity and conditions on the breeding ground and wintering grounds. The association of pintail productivity with habitat conditions differed between early (1961-1985) and recent (1986-2013) time periods for all seasons. Cross-seasonal relationships were comparatively strong in the early years, and weakened or dissolved during the later years, which may indicate a change in how the pintail population is responding to environmental change throughout their annual cycle.