Climate variability and the timing of spring raptor migration in eastern North America

Abstract

Many birds have advanced their spring migration and breeding phenology in response to climate change, yet some long‐distance migrants appear constrained in their adjustments. In addition, bird species with long generation times and those in higher trophic positions may also be less able to track climate‐induced shifts in food availability. Migratory birds of prey may therefore be particularly vulnerable to climate change because: 1) most are long‐lived and have relatively low reproductive capacity, 2) many feed predominately on insectivorous passerines, and 3) several undertake annual migrations totaling tens of thousands of kilometers. Using multi‐decadal datasets for 14 raptor species observed at six sites across the Great Lakes region of North America, we detected phenological shifts in spring migration consistent with decadal climatic oscillations and global climate change. While the North Atlantic and El Niño Southern Oscillations exerted heterogeneous effects on the phenology of a few species, arrival dates more generally advanced by 1.18 d per decade, a pattern consistent with the effects of global climate change. After accounting for heterogeneity across observation sites, five of the 10 most abundant species advanced the bulk of their spring migration phenology. Contrary to expectations, we found that long‐distance migrants and birds with longer generation times tended to make the greatest advancements to their spring migration. Such results may indicate that phenotypic plasticity can facilitate climatic responses among these long‐lived predators.

Patterns and mechanisms of heterogeneous breeding distribution shifts of North American migratory birds

“…Migrants within partial migrant populations tend to be relatively short‐distance migrants compared to migrants from completely migratory populations. Short‐distance migrants may rely more on supplemental cues and be better able to track resources on breeding grounds compared to long‐distance migrants that rely on predictive cues, such as photoperiods (Sullivan et al ) and are constrained by more ‘hard‐wired’ migratory schedules (Ramenofsky et al ). These patterns are consistent with Hovick et al's () analysis of bird species occurring in the central United States which showed that short‐distance migrant distributions have shifted north and neotropical migrant distributions have not shifted.…”

The mechanisms of phenology: the patterns and processes of phenological shifts

“…Many studies find that long-distance migrants have shifted phenology less than short-distant migrants or non-migratory species (Butler 2003, Rubolini et al 2007a, Doxa et al 2012, Barto sov a et al 2014, Gill et al 2014, Kullberg et al 2015. However, there are notable exceptions: in some studies, long-distance migrants show larger phenological shifts than short-distance migrants (Jonz en et al 2006, Sullivan et al 2016 or residents (Rubolini et al 2007b).…”

Extreme weather affects Peregrine Falcon (Falco peregrinus tundrius) breeding success in South Greenland

“…Even the NAO may or may not affect the Peregrine's shift towards earlier arrival and may consequently result in earlier breeding and hatching (review in Haest et al 2017). The long-term consequence of earlier breeding and hatching may be a mismatch between the Peregrine's highest food demand during the breeding season and peak prey abundance, which may lead to reduced breeding success (Parmesan 2006, Sullivan et al 2015.…”