Natura Croatica Issue number: Natura Croatica, Vol. 20 No.1

Neka obilježja gniježđenja bijele pastirice (Motacilla alba) u sjeverozapadnoj Hrvatskoj

Authors: Zdravko Dolenec

Authors and affiliation

  • Zdravko Dolenec Department of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10 000 Zagreb, Croatia

Abstract

In this study, some key aspects of the breeding performance of the pied wagtail are reported for the first time in northwestern Croatian. Only first clutches are included. The average egg length was 20.04 mm, breadth = 14.96 mm, volume = 2276.41 mm³ and egg shape index = 1.34. Egg dimensions and shape index did not vary significantly among the years in the study period (2006 to 2008). Egg size differences of the pied wagtail in different clutch size classes were also not significant. Egg length and egg breadth had the significant positive correlation. Average full clutch size for three years combined was 5.29, ranged from four to six eggs and modal clutch size was five (63.1 %). There was no significant difference in clutch size across the three years. We did not find any evidence for negative or positive relationships between clutch size and egg size in the researched bird species.

Keywords

pied wagtail, egg dimensions, clutch size, northwestern Croatia