Differences in shifts of wintering and breeding ranges lead to changing migration distances in European birds

Abstract

Studies on the impact of climate change on the distributions of bird species in Europe have largely focused on one season at a time, especially concerning summer breeding ranges. We investigated whether migratory bird species show consistent range shifts over the past 55 yr in both breeding and wintering areas or if these shifts are independent. We then analyzed whether patterns in changing migration distances of Finnish breeding birds could be explained by habitat use, phylogeny or body size. We used long-term datasets from the Finnish ringing centre to analyze the mean wintering latitudes of 29 species of Finnish breeding birds, then used breeding distribution data to make predictions as to whether certain species were migrating shorter or longer distances based on the comparative shifts in the wintering and breeding grounds. Our data reveal species-specifi c diff erences in changing migration distances. We show that for many species, long-term shifts in wintering ranges have not followed the same patterns as those in the breeding range, leading to diff erences in migration distances over time. We conclude that species are not adjusting predictably to climate change in their wintering grounds, leading to changing migration distances in some, but not all, species breeding in Finland. Th is research fi lls an important gap in the current climate change biology literature, focusing on individuals ' entire life histories and revealing new complexities in range shift patterns.In recent years, climate change models have predicted that species ranges will shift towards the poles and mountaintops, and in many species these range shifts have already been documented (Parmesan 2006, Chen et al. 2011, Brommer et al. 2012). To date, most studies investigating range shift patterns focus on seasonal ranges of species, often concentrating on breeding populations (Th omas and Lennon 1999, Hitch and Leberg 2007, Devictor et al. 2008, Zuckerberg et al. 2009, Brommer et al. 2012, although a few have focused on wintering locations (Barbet-Massin et al. 2009, Chen et al. 2011. While important, these studies provide a limited view of the overall impact of climate change on species ranges, and comparisons across species show little to no consistency in how anthropogenic climate change has aff ected range shifts. Th is makes it particularly diffi cult to generalize and therefore to understand the mechanisms behind latitudinal range shifts as a response to climate change (Elmberg et al. 2014). In order to more fully assess responses of species to a changing climate, and to make better predictions regarding future persistence, it is important to gather information about how the entire annual cycle of an individual has changed over time . To do this for migratory species, we need long-term information about how both winter and summer ranges have changed over the past century.In contrast to breeding ranges, wintering areas of migratory species are often more poorly known and can be thus very diffi cult to study. Recent attempts in both Nor...

Differential winter and breeding range shifts: Implications for avian migration distances

“…We found that winter movements in COA were primarily occurring in a northward direction, with 51.9% of the species having a significant northward shift in the latitude component of their COA. Our results are consistent with the pole‐ward shifts documented in North American birds during the winter (La Sorte & Thompson, ) and in Europe (Potvin et al, ; Visser et al, ). Our reaffirmation of northward winter shifts was therefore not surprising, as birds are known to be physiologically constrained by winter temperatures (Root, ) and temperature‐driven northward shifts of wintering birds have been widely documented (La Sorte & Thompson, ; Lehikoinen et al, ; Pavón‐Jordán et al, ).…”

“…Birds have been shown to geographically track their historical climatic niches (Tingley et al, , Illán, et al ). While most studies focus on temporal changes occurring within a single season, there are few comparative studies looking at species‐specific shifts between two distinct periods (but see Potvin et al, ; Zurell, Graham, Gallien, Thuiller, & Zimmermann, ). We offer evidence that environmental variables are differentially tracked between seasons and that distributions throughout the annual cycle are independent.…”

“…They implicate climate change as the mechanism for birds wintering closer to their breeding grounds. Potvin, Välimäki, and Lehikoinen () found that winter and breeding range shifts do not necessarily occur at equal rates and not all species shift in the same direction, resulting in species‐specific changes in migration distance. This research also suggests flexibility in migratory behaviour, influenced by independent environmental changes occurring between ranges.…”

Large‐scale climatic drivers of regional winter bird population trends

“…Nevertheless, the mechanisms of impact could be different between these groups. In migratory species, a decrease in migration distances could cause shifts in abundance towards breeding areas (Visser et al ., ; Lehikoinen et al ., ,b), although this does not seem to be the case in all migratory populations (see Potvin et al ., ). Resident species, however, do not migrate, so other mechanisms must explain the pattern.…”

Temporal changes in abundance–occupancy relationships over 40 years

“…With continuing climate change, migratory distance is decreasing for at least some species (Curley, Manne, & Veit, 2019;Potvin, Välimäki, & Lehikoinen, 2016;Visser, Perdeck, Balen, & Both, 2009) as breeding and wintering ranges differentially shift. One possible mechanism for different occupancies is an earlier return to breeding grounds in recent years, resulting in stronger competition (by migrants) for breeding territories (and thus, larger occupancy for migrants).…”