Rationale: By combining precision satellite-tracking with blood sampling, seabirds can be used to validate marine carbon and nitrogen isoscapes, but it is unclear whether a comparable approach using low-precision light-level geolocators (GLS) and feather sampling can be similarly effective.
Methods: Here we used GLS to identify wintering areas of northern gannets (Morus bassanus) and sampled winter grown feathers (confirmed from image analysis of non-breeding birds) to test for spatial gradients in δ13 C and δ15 N in the NE Atlantic.
Results: By matching winter-grown feathers with the non-breeding location of tracked birds we found latitudinal gradients in δ13 C and δ15 N in neritic waters. Moreover, isotopic patterns were best explained by sea surface temperature. Similar isotope gradients were found in fish muscle sampled at local ports.
Conclusions: Our study reveals the potential of using seabird GLS and feathers to reconstruct large-scale isotopic patterns.
© 2023 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.