Why Monitoring Yelkouans in the Bosphorus is so Important?

It’s that time of the year again! February is coming, so the peak period for yelkouan shearwater passage in the Bosphorus… It’s our third year in covering the first week of February with coastal counts. We are counting yelkouan shearwaters everyday for the sake of catching the highest numbers passing the strait in a single day. But why monitoring yelkouans in the Bosphorus is such an important issue? To answer, let’s take a look at which point we are now in terms of understanding this species in the Mediterranean Basin.

Yelkouan Shearwaters in the Bosphorus © Serhat Tigrel

Yelkouan Shearwaters in the Bosphorus © Serhat Tigrel

Until few years ago we knew that yelkouan shearwaters were breeding in some countries around the Mediterranean and breeding success was very low due to invasive predators such as rats and cats. So the seabird scientist around the Mediterranean decided to take conservation actions to save the species. So far so good. They invested a lot in understanding their breeding behaviours and securing the breeding pairs and chicks at colonies. But wait… Yelkouans are spending most of their life in open seas (as many other seabirds). They are visiting the land only for breeding. So protecting them on their breeding grounds is somehow not the total conservation action needed, we need to protect them at sea too. Sounds easy? It’s not. A great challenge in seabird conservation is figuring out where breeding pairs are going after the breeding season.

Here comes the importance of the Bosphorus in yelkouans shearwater’s life cycle. It is not 100% certain yet but from few studies in which the birds tracked after the breeding season, we know that central Mediterranean breeders are migrating to the Black Sea to spend their time until the next breeding season. However the proportion of the population using this migration route is not clear. A research done in France showed that large proportion of birds remaining in the central Mediterranean after the breeding season. No matter what proportion of the global population migrates to the Black Sea, we know that those birds using this migration route have to pass the Bosphorus as they don’t fly over the land. If we assume that large proportion of the global population using this migration route then it’s obvious that any potential large threat in the Black Sea or in the Bosphorus might wipe out these populations. If we are to protect yelkouan shearwaters efficiently then we definitely need to know about their movements between the Black Sea and the Mediterranean.

Together with tracking studies using high technology, applying the most basic techniques such as point count surveys to understand the movement of yelkouans and combining these informations are of high importance. For that reason we will be monitoring these enigmatic seabirds with coastal counts during the first week of February where the numbers are peaking in the Bosphorus. Fancy join us?

To volunteer for the 3rd coastal count period please contact us.