Open AccessHäckningsbiologiska studier av smålommar Gavia stellata på Holmöarna, Norra Sverige
Author(s) -
Cecilia Olsson,
Jan Pettersson,
Frank Johansson
Publication year - 2021
Publication title -
ornis svecica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.104
H-Index - 14
eISSN - 2003-2633
pISSN - 1102-6812
DOI - 10.34080/os.v31.22276
Subject(s) - archipelago , fishing , geography , population , fishery , commercial fishing , vegetation (pathology) , ecology , biology , archaeology , demography , medicine , pathology , sociology
The aim of this study was to estimate number of breeding pairs, breeding success, and distance to fishing areas in a population of the Red-throated Loon Gavia stellata on two of the main islands in the Holmöarna Archipelago in the northern part of the Baltic Sea, Sweden. Potential breeding waters were surveyed during seven years, 2010–2015 and 2019. Red-throated Loons appeared in 43 of the 135 lakes of sufficient size on the islands, and the population was estimated to 25–35 pairs, or about 2% of the Swedish population. The mean size of lakes with breeding pairs was 1.6 ha, and these lakes had an average of 82% water surface without vegetation (18% vegetation cover). The mean breeding success was low, 0.30 chicks per pair and year, and at least during one year, chicks were produced in only 20 (47%) of the surveyed lakes. The average distance between the nesting waters and the fishing areas for 17 studied pairs was 1.8 km. We discuss the characteristics of suitable nesting waters as well as the factors contributing to the low reproduction.