For several weeks now, we have been encountering large flocks of Yelkouan shearwaters (Puffinus yelkouan) daily in the Kvarnerić area. These small seabirds belong to the order Procellariiformes, also known as tubenoses. The size of the flocks we’ve observed ranges from about thirty to more than 500 birds. According to our estimates, up to 1,000 individuals are currently present in the Kvarnerić, which likely represents almost the entire national population, considering that around 300 to 400 breeding pairs are estimated to nest in the central Adriatic.

Although they can effortlessly follow the sea surface and waves in flight for a short time, shearwaters are not the most skillful fliers in their group. Unlike the well-known albatrosses (also tubenoses), which can glide through the air for days on their large wings, shearwaters are best recognized in flight by their rapid wingbeats. When hunting for fish, they dive underwater using their wings like flippers, and they also dive to escape danger when they are unable to take off from the surface. Their diet mainly consists of small pelagic fish.

In Croatia, Yelkouan shearwaters nest on offshore islands and islets of the central Adriatic, particularly around Vis and Lastovo. They build their nests in holes and crevices in the ground, which makes them especially vulnerable to rat predation. Rats, introduced to almost all islands and islets, eat the birds’ eggs and attack chicks. In March, the female lays a single egg, which both parents incubate. After the chicks fledge, the birds leave the colony. Typically, all birds have left the breeding sites by July and begin their search for food. As far as is known, most birds spend the winter in the northern Adriatic. In Croatia, Yelkouan shearwaters are a protected species and are considered vulnerable.