Preliminary results of the Capercaillie Tetrao urogallus recovery program in Bory Dolnośląskie Forest, SW Poland
Auteurs : Merta (D.), Kobielski (Janusz), Krzywinski (A.) et Rzonca (Zenon)
Année de publication : 2013
Publication : Vogelwelt
Volume :
134
Pagination : 65-74
Résumé :
In order to re-establish Capercaillie population in the Bory Dolnośląskie Forest, 78 young Capercaillies (45 cocks and 33 hens) from Polish breeding farms were released between 2009 and 2012 in the Ruszów Forest District. The Capercaillies from Kadzidłowo were reared by a ‘born to be free’ method. They were brought to the place of release together with their mothers. The mother was kept in a permanently closed aviary and remained there until the time of natural dispersion of the young. The adaptation of released birds was carried out in a special area (18 ha) where the Capercaillies were protected from terrestrial predators. More than 60 % of young Capercaillies were fitted with telemetric transmitters. The combined activity range of Capercaillies released in 2009-2011 (n = 33) assessed by the MCP method was 45,360 ha (females: 42,485 ha, males: 16,585 ha), and together with data from observations 91,196 ha. The activity range of Capercaillies from Kadzidłowo amounted to 20,723 ha while for the birds from the Wisła breeding centre it was twice as large (41,834 ha). The average size of activity ranges calculated for 33 birds released during 2009-2011 was 3,918 ha. 85 % of the birds survived the first four weeks after release, including 93 % of cocks, and 75 % of hens, while the survival of Capercaillies bred using the ‘born to be free’ method was 100 %. In the first year after release, the average survival was 165 days (median 107 days). It was longer for birds reared by the ‘born to be free’ method (average 227 days; median 139 days). In both groups, the cocks survived better (average 225 days; median 186 days) then the females (average 91 days; median 74 days). The main cause of death was predation (76 %). The most important predator was the Northern Goshawk (56 %), in particular for the hens (78 %). Martens (Martes spp.) were the most important predators killing Capercaillie cocks (43 %). The key measures include permanent monitoring and reduction of predation pressure in an area of c. 90,000 ha. Additionally, measures improving the quality of habitat and environmental education campaigns were carried out.