Morphology of Hatchling Hooded Crows and Its Relation to Egg Volume

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Abstract
The relationshp between egg volume and the size of hatchlng Hooded Crows Corvus corone cornix, was studied in 1982 and 1984, and in the Trondheim area. Central Norway. A high positive correlation was found between egg volume and the magnitude of all the morphological characters studied (total body mass, net body mass, tarsus length, wing length, bill tip length, and claw length), and between egg voume and the yolk sac mass of the hatchling. There was a tendency for a relative increase in yolk sac mass with increasing egg volume. There was also a positive correlation between the magnitudes of the different morphological characters of the hatchlings. When making a principal component analysis of the morphological, yolk sac, and egg volume data, four groups were separated. The middle toe and claw length had high scores on one component, the yolk sac on a second component, the tarsus length on a third component, and the other morphological characters and egg volume had moderate to high scores on all three components. At hatching, the bill tip was the most developed feature, compared to the same character for nestlings 24 days old, followed by the lengths of the tarsus, middle toe, claw, wing, and total body mass. The order of development of the different morphological characters during the embryonic stage was adapted to the hatchling''s needs during the hatching process.