Climate change and shifting arrival date of migratory birds over a century in the northern Great Plains

Abstract

Studies of the effects of climate change on migratory bird behavior have established that many species are shifting the average day of year of their arrival at nesting sites earlier. If migrating birds are adapted to arrive at the optimum stage in the growth season to maximize the availability of resources, then migration phenology shifts may result in arrival at nesting sites at selectively disadvantageous points in seasonal development of the nesting ecosystem. First arrival dates (FAD) are changing for many species, but we know little about shifts in the corresponding accumulated growing degree units (AGDU) of arrival date in association with increasing global temperatures. By transcribing field notes for migrant arrival times during the years of 1910-1950 in the region around Fargo, ND, we obtained a detailed and robust description of historical phenological patterns. Comparison of the arrival times of 83 of the same species in the same location over the past 10 years indicate that the majority of bird species studied are arriving earlier than they did historically. The accumulated growing degree units at the time of arrival deviated from past values by as much as 4-5% higher or lower depending on the species. In general, short-distance migrants have advanced their arrival times and reduced the AGDU at the time of arrival relative to long-distance migrants. These results indicate that changing climate is influencing bird migration patterns and leading to arrival of migrants at different points in the progress of the growing season relative to the past. The impacts of this divergence on fitness and selection are expected to influence the nature of future bird communities.

Migration distance, ecological barriers and en‐route variation in the migratory behaviour of terrestrial bird populations

“…For example, structured arrival and breeding schedules of long‐distance migrants have resulted in phenological mismatches as seasonal resource availability on the breeding grounds changes as a result of climate change (Both et al ., ; Møller et al ., ; Saino et al ., ). In general, short‐distance migrants have greater ability to adjust their migration and breeding schedules in response to gradual (Kullberg et al ., ; Travers et al ., ) or abrupt (La Sorte et al ., ) changes in seasonal resource availability. The positive relationship we documented between migration distance and en‐route variation in migratory behaviour may allow for the maintenance of structured arrival and breeding dates.…”

Determinants of Motives for Land Use Decisions at the Margins of the Corn Belt

“…Growing degree days have increased in the area (Travers et al, 2015), allowing for longer season crop varieties but precipitation trends are much less clear (National Climate Assessment, 2014). Wetlands in the area are typically ephemeral or impermanent and the region passes through wet and dry intervals of several years.…”

Subarctic‐breeding passerines exhibit phenological resilience to extreme spring conditions

“…Trends toward earlier arrival appear to be more widespread and of greater magnitude in short‐distance migrants (e.g., Butler , Mills , Travers et al. ) compared to long‐distance migrants (but see Hüppop and Hüppop , Stervander et al. , Jonzén et al.…”