The length and breadth of 334 eggs (82 clutches) of Branta canadensis interior were measured and 125 eggs (30 clutches) were weighed. Published and unpublished data for eggs of Branta canadensis maxima, hutchinsi, moffitti, and minima were also used and comparisons made with published data on 31 other species from seven ordersMeasurements of full clutches rather than of one egg per clutch proved advantageous. The means for length (L) and breadth (B) were 83.87 ± 0.366 mm and 56.60 ± 0.126 mm; those for the indices of volume (LB2), shape (100B/L), and density (100W/LB2), 268.98 ± 1.897 cm3, 67.34 ± 0.248, and 55.21 ± 0.190; that for weight (W), an estimated 1.5 days after the commencement of incubation, 150.02 ± 1.718. The clutch variances were significant and accounted for about half the total variance. The lightest egg weighed 68% of the heaviest and the coefficients of variation varied from 2.48 (breadth) to 7.17 (weight). The last eggs were significantly lighter and smaller than earlier eggs, owing to their lesser breadth. Correlations between egg size and clutch size were not constant. Correlations between length and breadth were generally positive, those between volume and shape generally negative. The mean true density of the eggs was estimated to be 1.085, the mean true volume 137.74 cm3, the mean fresh weight 150.95 g, and the mean of the factor k for the correction of the ellipsoidal volume, 0.9780. All differences between the five races for length, breadth, and volume were significant. Joint non-overlaps varied from 64 to 100%.
Breeding and Non-Breeding Range of Canada, Branta canadensis, and Cackling Geese, Branta hutchinsii, in the Eastern Canadian Arctic