Using GPS tracking and stable multi-isotopes for estimating habitat use and winter range in Palearctic ospreys

Flavio Monti,Gaël Guillou,Antoni Muñoz Navarro,Olivier Duriez,Jean-Marie Dominici,Ilham Bentaleb,Andrea Sforzi,Aloїs Robert,Rafel Triay Bagur

doi:10.1007/s00442-021-04855-5

Abstract

We used both satellite tracking and carbon, nitrogen and sulphur stable isotopic analysis (SIA) to infer wintering ecology and habitat use of the Corsican osprey Pandion haliaetus population. A control sample of feathers from 75 individuals was collected within the osprey’s northern hemisphere breeding range, to assess the SIA variability across habitat types. An experimental set of SIA on feathers of 18 Corsican adults was examined to infer wintering ground locations and habitat types used during the non-breeding period. We calibrated the SIA using GPS/GSM tracks of 12 Mediterranean adults’ movements as wintering site references. We found 50% of individuals were resident and the other half migrated. Ospreys spent the winter at temperate latitudes and showed a high plasticity in habitat selection spread over the Mediterranean basin (marine bays, coastal lagoons/marshland, inland freshwater sites). Complementary to GPS tracking, SIA is, at a broad geographical scale, a reliable method to determine whether ospreys overwinter in a habitat different from that of their breeding area. This study proved that the integration of SIA and GPS/GSM tracking techniques was effective at overcoming the intrinsic limits of each method and achieving greater information for basic ecological studies of migratory birds in aquatic environments.

Highlights

Animal population dynamics are dependent on a series of factors, which occur during different periods of the annual cycle (Newton 2003)
Results were concordant with the ecology of osprey breeding populations
These trends allow the comparison of isotopic ratios in Corsican adult ospreys feathers with those of Corsican chicks fed in a marine habitat in the Mediterranean

Summary

Introduction

Animal population dynamics are dependent on a series of factors, which occur during different periods of the annual cycle (Newton 2003). To assess the isotopic method we used the GPS tracking data of ospreys’ movements as a reference for migratory routes and wintering sites’ location and habitat, allowing calibration of the isotopic composition with wintering locations We expect these isotopic ratio values in osprey feathers to be potential proxies (a) to investigate latitudinal variation (Kelly et al 2002; Farmer et al 2004) and locate ospreys’ wintering grounds at a broad geographical scale; and (b) to link aquatic habitat types to different foraging areas in winter (Hobson 1999; Romanek et al 2000)

Materials and methods

Discussion

Compliance with ethical standards