Bearded Tit (Panurus biarmicus) Science Article 3
abstract
The variation in size and shape of Bearded Tit eggs was investigated in the Wielkopolska Region of western Poland in 1988-1992 and 1997-2000. The mean clutch size was 5.47 (95% CL: 5.25-5.70, n = 99), and differed markedly from year to year. Coefficients of variations for the mean egg characteristics in a clutch ranged from 1.91 (breadth) to 4.90 (volume). No significant correlation between egg length and breadth was found. Repeatability estimates were 0.50, 0.48, 0.50, 0.47 for length, breadth, volume and elongation index, respectively. The results suggest a relatively low heritability of egg dimensions in the population studied
Surmacki A., Stepniewski J., Zduniak P., Acta Ornithol. 38: 123-127