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

11. Bullock's Oriole

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.

BULLOCK'S ORIOLE NESTING INFORMATION (From birdsoftheworld.org)

Nests - In breeding areas, pairs form soon after arriving and migratory individuals are generally seen in small, loose flocks that may include both sexes. Males generally arrive on breeding grounds before females. Nesting begins 1–2 wk after arrival on the breeding grounds. Nests are commonly placed in isolated trees, at edges of woodlands, along wooded watercourses (sometimes hanging over water), in shelterbelts, and in urban parks. Generally only female weaves nest, but male may assist, with one working on inside and other on outside, bringing nesting material. Nest may take up to 15 d to build. Nests are typically pensile , often suspended from a few thin branches.
Eggs - Oval to long oval, ground color typically pale bluish or grayish white, sometimes with purplish tint, splotched and scrolled with a few to many fine, purplish brown lines; markings denser at large end of egg. Clutch size usually 4 to 5 eggs.
Incubation - Only female incubates, but male closely attends nest. 11 - 14 days
Fledging - Young are altricial. Both parents feed young at equal rates. Young leave nest about 2 wk after hatching.

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