Geolocators reveal migration routes, stopover sites, and nonbreeding dispersion in a population of Cerulean Warblers

Abstract

Cerulean Warblers (Setophaga cerulea) are among the fastest declining Nearctic-Neotropical migrant wood-warblers (Parulidae) in North America. Despite ongoing conservation efforts, little is known about their non-breeding distribution. In June 2016-2018, we deployed geolocators (n = 30) on adult male Cerulean Warblers in Indiana, USA, to track annual movements of individuals. Recovered geolocators (n = 4) showed that Cerulean Warblers occurred broadly throughout northern South America. Autumn migration lasted 44-71 days (n = 4), whereas spring migration lasted 37-41 days (n = 3). The average migration distance was 5268 km. During autumn migration, Cerulean Warblers made 1-4 stopovers (i.e., ≥2 days; n = 4) and 1-2 stopovers during spring migration (n = 3). When crossing the Gulf of Mexico during autumn migration, two birds stopped over after crossing, but not beforehand. Two others navigated through the Caribbean rather than crossing the Gulf of Mexico. During spring migration, one individual stopped after crossing, one individual stopped before crossing, and one individual stopped before and after crossing the Gulf of Mexico. No birds migrated through the Caribbean Islands during spring migration. These results represent novel information describing annual movements of individual Cerulean Warblers and will inform conservation efforts for this declining species.

No “carry-over” effects of tracking devices on return rate and parameters determining reproductive success in once and repeatedly tagged common swifts (Apus apus) a long-distance migratory bird

“…Using a long-term data set of 66 common swifts tagged once or repeatedly and 56 non-logger birds from the same breeding colony in Germany, we detected no differences between logger and non-logger birds in different traits regarding apparent survival and life-history traits over eight years. The return rate of once tagged and repeatedly tagged logger birds did not differ from the return rate of non-logger birds, and the return rates were similar to return rates of other bird species of similar body weight or even less [17,20,21].…”

“…All this information contributes to a better understanding of life-history strategies in long-distance migratory bird species [9,10]. In recent years, tracking devices are getting smaller and lighter so that even small bird species (less than 100 grams) can be tracked [11][12][13][14], and the number of biologging studies on birds is constantly increasing [15][16][17][18]. So far, many studies investigated ecological carry-over effects in migratory species, i.e.…”

No “carry-over” effects of tracking devices on return rate and parameters determining reproductive success in once and repeatedly tagged common swifts (Apus apus), a long-distance migratory bird

“…Using a long-term data set of 66 common swifts tagged once or repeatedly and 63 non-logger birds from the same breeding colony in Germany, we detected no differences between logger and non-logger birds in different traits regarding apparent survival and life-history traits over eight years. The return rate of once tagged and repeatedly tagged logger birds did not differ from the return rate of non-logger birds, and the return rates were similar to return rates of other bird species of similar body weight or even less [17,20,21]. According to the capture-recapture analysis, apparent survival was similar for logger and non-logger birds and for both sexes.…”

“…All this information contributes to a better understanding of life-history strategies in long-distance migratory bird species [9,10]. In recent years, tracking devices are getting smaller and lighter so that even small bird species (less than 100 g) can be tracked [11][12][13][14], and the number of biologging studies on birds is constantly increasing [15][16][17][18]. So far, many studies investigated ecological carry-over effects in migratory species, i.e.…”

Las aves del departamento de Loreto, Perú

“…Ambas especies son migratorias del hemisferio norte, pero mientras que C. subruficollis es de hábitat acuático o de orilla, S. cerulea es de bosque. Esta última especie es una de las especies de parúlidos con mayor declinación de sus poblaciones reproductivas en Norteamérica y un paseriforme pequeño con uno de los viajes migratorios más largos (Welton et al 2012, Delancey et al 2020 Revista peruana de biología 28(especial): e21915 (Diciembre 2021) Biodiversidad de Loreto, Perú: conocimiento actual de invertebrados y vertebrados…”