*Oology is a branch of ornithology studying bird eggs, nests and breeding behaviour. The word is derived from the Greek oion, meaning egg.

4. Tree Swallow

This part of the Stanislaus Audubon Website is focused on 44 common Central Valley nesting species with background about their nesting habits. Please check the Great Valley Museum Central Valley Egg Collection starting page for links to all the featured species.

TREE SWALLOW NESTING INFORMATION (From birdsoftheworld.org)

Nests - Males usually arrive and defend nest cavity up to several days prior to female arrival (RRC), but sexes may occasionally arrive simultaneously. It is thought that pairing begins as soon as females arrive on breeding grounds. Early arriving pairs deposit a few pieces of nesting material in cavity shortly after pair formation, but actual nest construction usually begins several weeks later. Nest construction falls almost entirely to females. Most nest material is collected near the water's edge, or on the ground, usually within 30 m of the nesting site, and transported in the beak to the cavity, where it is shaped by the female scratching and pushing with her breast.
Eggs - Translucent, pale rosy pink when laid, becoming pure white at around 4 d of incubation, 4 to 7 eggs in clutch
Incubation - 11 to 20 day range, but incubation periods of 13 to 14 days most common
Fledging - period from hatching to departure from the nest ranges from 15 to 25 d, although most nestlings depart nest at an age of 18 to 22 d

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