Avian population consequences of climate change are most severe for long-distance migrants in seasonal habitats

Abstract

One consequence of climate change is an increasing mismatch between timing of food requirements and food availability. Such a mismatch is primarily expected in avian long-distance migrants because of their complex annual cycle, and in habitats with a seasonal food peak. Here we show that insectivorous long-distance migrant species in The Netherlands declined strongly (1984 -2004) in forests, a habitat characterized by a short spring food peak, but that they did not decline in less seasonal marshes. Also, within generalist long-distance migrant species, populations declined more strongly in forests than in marshes. Forest-inhabiting migrant species arriving latest in spring declined most sharply, probably because their mismatch with the peak in food supply is greatest. Residents and short-distance migrants had non-declining populations in both habitats, suggesting that habitat quality did not deteriorate. Habitat-related differences in trends were most probably caused by climate change because at a European scale, long-distance migrants in forests declined more severely in western Europe, where springs have become considerably warmer, when compared with northern Europe, where temperatures during spring arrival and breeding have increased less. Our results suggest that trophic mismatches may have become a major cause for population declines in long-distance migrants in highly seasonal habitats.

What prevents phenological adjustment to climate change in migrant bird species? Evidence against the “arrival constraint” hypothesis

“…Such 32 mismatching is seen in a range of bird species (e.g. Buse et al 1999;Reuter and Breckling 1999;Stenseth and Mysterud 2002), but population-level consequences appear particularly severe for migrants (Both et al 2009). …”

Climate change suggests a shift of H5N1 risk in migratory birds

“…In general terms, species distribution, migratory routes and behaviour of migratory birds are highly dependent upon climatic conditions, especially for long-distance migratory birds subject to seasonal variation in food availability (Both et al, 2010;Gilbert et al, 2008;Jonzén et al, 2006). Rising global temperatures may impact substantially the geographical distribution of migratory birds and the diseases they carry, including HPAI H5N1.…”

Stage-dependent survival in relation to timing of fledging in a migratory passerine, the Northern Wheatear (Oenanthe oenanthe)

“…In particular, post-fledging survival of late fledglings may be lower that of than early fledglings because food availability may decline during the breeding season, such as reported for temperate, deciduous forests (Feeny 1970;Southwood et al 2004;Both et al 2010). However, other ecosystems such as marshes harbor relatively high densities of arthropods throughout the season (Halupka et al 2008;Both et al 2010).…”

“…However, other ecosystems such as marshes harbor relatively high densities of arthropods throughout the season (Halupka et al 2008;Both et al 2010). Data on changes in food abundance throughout the breeding season are largely unavailable for coastal dunes in Western Europe.…”