Both short and long distance migrants use energy-minimizing migration strategies in North American herring gulls

Abstract

Background: Recent studies have proposed that birds migrating short distances migrate at an overall slower pace, minimizing energy expenditure, while birds migrating long distances minimize time spent on migration to cope with seasonal changes in environmental conditions. Methods: We evaluated variability in the migration strategies of Herring Gulls (Larus argentatus), a generalist species with flexible foraging and flight behaviour. We tracked one population of long distance migrants and three populations of short distance migrants, and compared the directness of their migration routes, their overall migration speed, their travel speed, and their use of stopovers. Results: Our research revealed that Herring Gulls breeding in the eastern Arctic migrate long distances to spend the winter in the Gulf of Mexico, traveling more than four times farther than gulls from Atlantic Canada during autumn migration. While all populations used indirect routes, the long distance migrants were the least direct. We found that regardless of the distance the population traveled, Herring Gulls migrated at a slower overall migration speed than predicted by Optimal Migration Theory, but the long distance migrants had higher speeds on travel days. While long distance migrants used more stopover days overall, relative to the distance travelled all four populations used a similar number of stopover days. Conclusions: When taken in context with other studies, we expect that the migration strategies of flexible generalist species like Herring Gulls may be more influenced by habitat and food resources than migration distance.

Age and season predict influenza A virus dynamics in urban gulls: consequences for natural hosts in unnatural landscapes

“…2016, Anderson et al. 2019, 2020), suggesting that band resights provided a good insight into movement patterns in our gull populations. Juveniles undertaking longer migrations may expand the host contact network and increase the potential for exposure to novel pathogens, against which they are immunologically naïve.…”

Differential migratory movements of geographically distinct wintering populations of a soaring bird

“…Avian migrants often exhibit spatiotemporal variation in the mode, speed, and duration of ights in response to changes in climate, wind, and food availability [15,[61][62][63]. Migratory birds may y faster in spring migration than in autumn migration for timely arrival at the breeding ground [64].…”

Eurasian Stone-curlews Burhinus oedicnemus breeding in Italy show a remarkable inter and intra-population variability of migratory behaviour

“…The extent and the pattern of migration may vary strongly among different taxa and even within the same taxon (Dingle & Drake 2007). Migratory behaviour in birds, in particular, shows a remarkable variability at species (Schmaljohann 2018, Anderson et al . 2020), population (Monti et al .…”

“…The extent and the pattern of migration may vary strongly among different taxa and even within the same taxon (Dingle & Drake 2007). Migratory behaviour in birds, in particular, shows a remarkable variability at species (Schmaljohann 2018, Anderson et al 2020, population (Monti et al 2018, Phipps et al 2019 and individual levels (Shamoun-Baranes et al 2017, Tedeschi et al 2019. One of the most extreme forms of intra-population variation in migratory behaviour is partial migration, where only a fraction of individuals are migrants (Chapman et al 2011(Chapman et al , 2014.…”