Autumn migration and wintering site of a wood warbler Phylloscopus sibilatrix breeding in Denmark identified using geolocation

Abstract

Background: Basic knowledge of detailed spatiotemporal migration patterns is lacking for most migratory bird species. Using the smallest available geolocator, we aim to map autumn migration and wintering areas of north European wood warblers Phylloscopus sibilatrix and compare the spatiotemporal pattern with recoveries of individuals ringed across Europe. Results: A tracked wood warbler migrated south-southeast to sub-Saharan Africa in Sudan and then west-southwest to winter in Côte d'Ivoire. The timing and route fits well within the distribution of ring recoveries although the westward movement after the Sahara crossing is not revealed by the ring recoveries, but only few recoveries south of Sahara exist. Conclusions: The surprising westward movement south of the Sahara supplements the overall pattern revealed by ring recoveries and aids our understanding of the connectivity and site dependence in this generally declining species.

Spatial behavior and habitat use in widely separated breeding and wintering distributions across three species of long‐distance migrant Phylloscopus warblers

“…At least on a broad scale, the wintering areas of tracked birds appear to encompass that occupied by the studied breeding populations as confirmed by both geolocator and ringing data Tøttrup, Pedersen, & Thorup, 2018;Wernham, 2002). At least on a broad scale, the wintering areas of tracked birds appear to encompass that occupied by the studied breeding populations as confirmed by both geolocator and ringing data Tøttrup, Pedersen, & Thorup, 2018;Wernham, 2002).…”

“…We acknowledge that tracking the same individuals in both seasons would have been the most appropriate way to assess the relationship between breeding and wintering behavior and habitat but, given the small size of the species involved, the lack of adequate miniaturization of technology prevents this. At least on a broad scale, the wintering areas of tracked birds appear to encompass that occupied by the studied breeding populations as confirmed by both geolocator and ringing data Tøttrup, Pedersen, & Thorup, 2018;Wernham, 2002).…”

“…Willow warblers were tracked in 2013 and 2015, wood warblers were tracked in 2013 and 2014, and chiffchaffs were tracked in 2015. In winter, willow warblers were tracked at two sites in dry Savannah forest in Northern Ghana (9.09°N, 1.82°W), which is within the known wintering area of Danish breeding birds (Lerche-Jørgensen, Willemoes, Tøttrup, Snell, & Thorup, 2017), while wood warblers were tracked at a site in the Guinea forest-savannah transition zone in Southern Ghana (6.65°N, 0.7°W) in the same region as a Danish breeding bird wintering in Cotê d'Ivoire (Tøttrup, Pedersen, & Thorup, 2018). Chiffchaffs were tracked at a field site dominated by tamarisk Tamarix sp.…”

Autumn migration direction of juvenile willow warblers (Phylloscopus t. trochilus and P. t. acredula) and their hybrids assessed by qPCR SNP genotyping

“…However, the route across the central Mediterranean Sea is nonetheless a major migration route for some other species of songbirds, e.g. wood warblers [31] and sedge warblers [32]. It is possible that these species are better-adapted to this route than hybrid willow warblers, by for example putting on more fat reserves before crossing the Sahara.…”

Autumn migration direction of juvenile willow warblers (Phylloscopus t. trochilus and P. t. acredula) and their hybrids by qPCR SNP genotyping

“…However, this route across the central Mediterranean Sea is the major migration route for some other species of songbirds, e.g. wood warblers [29] and sedge warblers [30]. It is possible that these species are better-adapted to this route than hybrid willow warblers, by for example putting on more fat reserves before crossing the Sahara.…”