Sandwich terns with colour rings at Pomorie Lake

Sandwich terns with colour rings at Pomorie Lake

During the past month the migration of Sandwich terns (Sterna sandvicensis) from the Black Sea is continuing to be intensive. At Pomorie Lake the numbers of feeding and roosting terns have been varying significantly – from 30 to 300. Several Sandwich terns marked with colour rings have been observed. Birds were hatched in the Pomorie Lake colony in the period 2010-2013 when in total more than 250 chicks were ringed during a study of their migration and life duration.

Sandwich tern hatched in 2010 and ringed on 23 June of the same year in the natal colony with a green ring with white code CAD was observed at the traditional resting site on the wooden sticks in front of the Pomorie Lake visitor centre on 23 October this year. Interesting about that bird is that it was observed abroad – in January 2013 it has been on the Mediterranean coast of Spain at Cambrils, Tarragona. In July 2014 it was recorded again at Pomorie Lake and until last week we didn’t know what was its fortune.      

Other three Sandwich terns hatched in 2012 and ringed on 26 June in the natal colony have been also recorded lately at the saline lagoon. First one is marked with orange ring with black code CBJ and was observed on 1 November and in the end of March this year at the same place. Second won carrying orange ring with black CNH was recorded on 3, 26 and 28 October on the wooden sticks at the southern bank of the Pomorie Lake. The bird has not been recorded at the site for almost 3 years – since November 2014. Third bird has orange ring with black code CBP and was observed on 23 October – this being its first sighting after ringing.

We remind you that Pomorie Lake hosts one of the largest colonies in the Southeastern Europe of Sandwich terns – protected species that is flagship for the saline Pomorie lagoon. Thanks to the long -term efforts of Green Balkans volunteers for improving the nesting condtions numbers of breeding pairs jumped from 6 in 1996 to more than 2000 in 2013 and 2015. The colour ringing program was pilot for Bulgaria and thanks to it we learned about the long-distance travels of these elegant birds reaching Israel, Greece, Italy, Spain, Tunisia and Canary Islands.