Geographic variation in egg measurements (egg breadth, length, volume and shape index), was studied in Lapwing, based of the published data from Europe and Asia. Egg size was found to vary significantly with geographic location. Mean egg breadth and volume decreased with longitude and increased with latitude, and this relationship explained 42% and 49%, respectively of their variation among study areas. Mean egg length, and to lesser extent egg shape index, showed an U-shaped relationship with longitude, accounting for 29% and 20%, respectively of their variation between localities. The resultant NW- SE dine in egg size was well pronounced in Europe, with largest eggs laid in Great Britain, N Spain and Norway and smallest in SE Europe. Lapwings breeding in Asia laid eggs consistently narrower and less voluminous than European breeders. In E Asia egg length was however almost as long as in NW Europe. The geographic pattern in egg size corresponds with gradient in oceanic characters of the climate. Precipitation and temperature were suggested as possible factors affecting — via the level of food resources available to laying females — geographic variation in Lapwing egg size. Clinal variation in female body size might be another contributing factor.
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