Spring migration of Blackpoll Warblers across North America

Abstract

The awe-inspiring seasonal migrations of birds between breeding and wintering grounds has long attracted the interest of casual naturalists and professional ornithologists alike. Although new technologies improve our ability to follow individual migrants throughout their annual cycle, the scale and detail provided by banding records remain incredibly valuable. The focus of avian migration studies is often the most physiologically challenging migratory feats that sometimes leaves certain species or seasons relatively understudied. The Blackpoll Warbler (Setophaga striata) is well-known for its transoceanic migratory flight during fall migration, the season in which it is best studied, yet the details of its spring migration are not well known, at least not at a continental scale. Here we use spring migration banding data on over 15,000 Blackpoll Warblers from 28 banding sites across North America to describe the details of the spring migration patterns in this species. Our data, which spans almost 60 years, indicates that Blackpoll Warblers are migrating earlier at a rate of 0.5 days per decade. We also demonstrate an expected protandrous migratory pattern and an unexpected sex-dependent difference in migration speed with females migrating more quickly than males. Our analyses of longitudinal timing patterns reveal that passage through sites west of 85° occurs prior to passage at sites east of 85° and that this difference increases throughout the migratory period, indicating that birds using western sites are migrating faster. Additionally, we provide evidence vis-à-vis analyses of wing length that birds from eastern and western breeding locations mix at lower-latitude migratory sites but their migratory paths diverge as birds proceed north. These results indicate that birds migrating to western breeding sites differ in their migration speed and route thus compensating for the longer migratory distances traveled by western populations of Blackpoll Warblers compared to those breeding in eastern North America. Migration printanière de la Paruline rayée en Amérique du NordRÉSUMÉ. Les migrations saisonnières combien admirables des oiseaux entre leurs aires de nidification et d'hivernage ont depuis longtemps attiré l'attention des naturalistes occasionnels tout comme des ornithologues professionnels. Même si de nouvelles technologies ont permis d'améliorer notre capacité à suivre individuellement les oiseaux migrateurs tout au long de leur cycle annuel, l'échelle et les détails fournis par les retours de bagues ont toujours une très grande valeur. Les études sur les migrations aviaires portent souvent sur l'incroyable défi physiologique qu'elles représentent, ce qui entraine parfois un relatif sous-examen de certaines espèces ou saisons. La Paruline rayée (Setophaga striata) est bien connue pour sa migration transocéanique durant l'automne, saison à laquelle elle est le plus étudiée, mais les détails de sa migration printanière sont peu connus, du moins à l'échelle continentale. Nous avons utilisé les données de baguag...

Six decades of North American bird banding records reveal plasticity in migration phenology

“…Data on both spring and fall migratory seasons are available across large geographical and temporal scales, spanning more than 40° of latitude, 50° of longitude, and in some locations, nearly 60 years of observations. While a number of studies have documented advancement of spring migration in avian species (Covino, Morris, et al, 2020; Marra et al, 2005; Møller et al, 2008; Sparks et al, 2005; Van Buskirk et al, 2009), there are fewer examinations and more mixed patterns of how changing climates may impact fall migration phenology (but see Haest et al, 2019; Jenni & Kéry, 2003; La Sorte et al, 2015; Miles et al, 2017). Advancements of spring timing are relatively consistent and easily understood in the context of the fitness consequences, with birds arriving earlier to their breeding grounds showing greater reproductive success (Cooper et al, 2015; McKellar et al, 2013; Morrison et al, 2019).…”

Adult male birds advance spring migratory phenology faster than females and juveniles across North America

“…Age and sex, in particular, could affect both general migratory phenology, as well as phenological trends. In spring, males are expected to arrive earlier than females (protandry) to compete for territories and secure more mating opportunities (Canal et al, 2012; Coppack et al, 2006; Kokko et al, 2006; Morbey & Ydenberg, 2001; Rubolini et al, 2004; Saino et al, 2010), and protandry has been widely documented in Europe (Spina et al, 1994; Tøttrup & Thorup, 2008), Asia (Nam et al, 2011; Wobker et al, 2021), and North America (Covino, Horton, et al, 2020; Covino, Morris, et al, 2020; Francis & Cooke, 1986; McKinnon et al, 2016; Morris & Glasgow, 2001; Swanson et al, 1999). Although there has been no wide‐scale appraisal of sex‐specific phenology during fall migration (Stegman et al, 2017), single‐species studies have documented protogyny (females depart first; Mills, 2005), protandry (McKinnon et al, 2016), and no discernable sex‐specific differences (Covino, Horton, et al, 2020; Mills, 2005; Morris & Glasgow, 2001).…”

Migratory connectivity then and now: a northward shift in breeding origins of a long-distance migratory bird wintering in the tropics

“…However, we excluded Alaska because evidence from 16 tracked birds suggests that blackpoll warblers wintering in our study area are eastern in origin [31], and because birds from Alaska have longer wings on average (mean ± s.d. = 75 ± 2.1 mm [47,48]) than those at our study site (mean ± s.d. = 71 ± 2.1 mm; electronic supplementary material, figure S2).…”