Open AccessClutch and egg size variation in the Marsh Harrier Circus aeruginosus in eastern Poland
Author(s) -
Marcin Polak
Publication year - 2010
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.v20.22638
Subject(s) - avian clutch size , biology , marsh , clutch , bird egg , population , zoology , ecology , reproduction , wetland , physics , demography , sociology , thermodynamics
The main aim of this study was to examine how clutch size and season influenced egg size in a population of Marsh Harriers Circus aeruginosus in eastern Poland. The Marsh Harriers nested in small, isolated patches of reed belts surrounding fish ponds. A total of 328 eggs from 70 clutches were measured during four nesting seasons (2005–2008). Average clutch size was 4.69 ± 0.71 eggs and did not vary between years; the modal clutch size was 5 eggs. Mean values of the egg dimensions were: egg length = 48.60 ± 1.78 mm; egg breadth = 38.36 ± 1.13 mm; egg volume = 36.53 ± 2.99 cm3. There was a strong correlation between egg length and egg breadth. The number of eggs in a clutch had no effect on the egg size.