First monitoring of breeding Common terns was performed in Niedus ornithological reserve
23-05-2019
The first detailed monitoring of the breeding terns in Niedus ornithological reserve was performed on May 21, 2019. Previously only preliminary observations were done, including the total abundance on the breeding site and time of return from the wintering grounds. The main aim of the detailed monitoring – to measure the abundance and breeding success of the Common terns’ population, to evaluate the effectiveness of the practical conservation measures, implemented within the project.
Fifteen years ago, more than 100 pairs of the breeding Common terns yearly were counted in Niedus ornithological reserve, however due to the natural succession and overgrow of the islands with wooden high vegetation, the site lost its importance for these birds. These changes resulted in the significant decrease of birds – a few years ago only 10 to 25 pairs of Common terns were breeding on the islands.
In 2017-2019 the LOD implemented practical habitats management works on the islands, when the vegetation was moved for a few times. The favourable conditions of the open habitats were re-established, and it resulted into the obvious increase of the Black-headed gulls and Common terns. During the monitoring, the staff of the LOD and Viesiejai Regional Park Administration discovered 43 nests with 117 eggs of Common terns. Not all terns already laid the eggs, therefore it is expected, that during the second count in June more nests will be found. Seeking to evaluate the results of both visits, every nest was marked with a stick with unique number of the nest.
In addition to Common terns, 400-500 pairs of Black-headed gulls, Northern Lapwing and Western Marsh Harrier were observed.
Photos by Marius Karlonas
