Swiss Ornithological Institute

Our clients come from a wide range of research sectors, and today, we focus on Dr Martins Briedis from the Swiss Ornithological Institute, based at Sempach in Switzerland.

Martins’s research focuses primarily on bird migration, mainly using multi-sensor geolocator tracking, but also some other tools, like stable isotopes.

“We have been working on describing migration patterns of Common Starlings in Latvia since 2020 and through geolocator tracking we managed to find out that some birds leave their breeding sites right after the breeding is finished in mid-June while some other stay around until late autumn (published here: https://nsojournals.onlinelibrary.wiley.com/doi/full/10.1111/jav.03080).

“But the problem with using geolocators for tracking is that you need to recover the devices a year later once the birds have completed their migration journey and return to the breeding sites next spring. Because mortality is high, we only get back about 20% of geolocators that we put out, thus we do not know what most birds are actually doing.

“This is where stable isotopes come in – since the birds moult their feathers in summer, using stable isotopes we try to delineate what proportion of birds are staying in Latvia until late autumn and what proportion is moving away to Germany already in mid-June base on isotopic differences in their feathers. Thus, we are able to get feather samples from birds during the breeding time in May in Latvia and using stable isotopes, see where they have moulted their feathers last summer.

“Our first paper on this has just been accepted for publication in Ibis – “Combining δ2H and δ34S stable isotopes identifies diverse moult strategies in a short-distance migratory bird” [link to https://onlinelibrary.wiley.com/doi/full/10.1111/ibi.70043?campaign=wolearlyview].

“In the second step, which we hope to complete this year, we want to see how this moult-migration strategy has changed over time in the Baltic population of Starlings. Thus, the recent batch of feathers that were analysed for stable isotopes include tens of samples collected from museum specimens in Estonia, Latvia, and Lithuania. Museum specimens include birds as old as 100 years, and we hope that using stable isotopes we will be able to tell what their moult migration strategy has been (either leave in early summer after breeding or stay in the Baltics until late autumn). Therefore, we want to see if the prevalence of these two strategies has changed over the last century along with the changing climate.”

When the samples Martins describes above land at Isolab Scientific, we analyse feather and claw samples using our Sercon Pyro‑Earth and Sercon 20‑22 EA‑IRMS systems to measure hydrogen and sulphur isotopes. After cleaning and homogenising each sample, small amounts are converted to gas and separated with high precision before isotope ratios are measured. Every run includes internationally calibrated standards and in‑house QC to ensure accuracy and traceability. 

The Swiss Ornithological Institute Sempach is a non-profit foundation for ornithology and bird conservation. It monitors native bird fauna, researches their way of life and advocates for species conservation. It takes care of injured and orphaned birds, informs and advises the population and runs a visitor centre in Sempach.

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