A kárókatona fészekalj és tojásméret vizsgálata a Kis-Balatonon és a Nagyberekben

Study on some breeding parameters of the Great Cormorant (Phalacrocorax carbo sinensis) was carried out in 2005 on Kis-Balaton and in 2009 in the Nagyberek Fehérvíz Nature Conservation Area. Mean (±SE) of clutch size was 3.51±0.15 (N=41) on Kis-Balaton and 3.27±0.19 (N=11) on Nagyberek while ranges of clutch size were 1–6 and 3–5, respectively, that didn’t show significant differences (F= 0.38, p= 0.68) compared with earlier Hungarian data. Mean of egg sizes (length±SE x width±SE), shape index and egg volume were 62.0±0.2 x 39.1±0.1 mm, 1.59±0.01 and 48.38±0.34 cm3 on Kis-Balaton (N=137), while their values were respectively 61.6±0.5 x 38.2±0.2 mm, 1.61±0.02 and 45.94±0.69 cm3 on Nagyberek (N=29). Egg weight was measured only on Kis-Balaton (53.0±0.4 g, N=135). Comparing the results of the two areas, significant differences were found on egg width (t=3.15, p=0.002) and volume (t=3.02, p=0.003), while no statistical differences were found when comparing the other egg parameters measured.