*Oology is a branch of ornithology studying bird eggs, nests and breeding behaviour. The word is derived from the Greek oion, meaning egg.
21. Tricolored Blackbird
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.
TRICOLORED BLACKBIRD NESTING INFORMATION (From birdsoftheworld.org)
Nests - The male begins singing as early as late February. The male typically arrives at breeding sites before the female, but at some sites both sexes arrive and initiate breeding the same day. Most initial nesting in the San Joaquin Valley and surrounding areas occurs from late March to April; by late April, most birds are associated with breeding colonies. Requirements for breeding colony sites are: (1) accessible freshwater, (2) protected nesting sites (flooded or thorny or spiny vegetation), and (3) suitable foraging area providing adequate arthropod prey within a few kilometers of the nesting colony. Nest construction, exclusively by the female, may be initiated upon arrival at a breeding colony. The Tricolored Blackbird constructs open-cup nests with lower and outer layers of long leaves (e.g., cattail thatch, annual grasses, entire forbs, stems and leaves) woven tightly around supporting stems.
Eggs - Eggs are typically oval, varying from short oval to long oval. Ground color is typically pale blue, but uncommonly pale olive green, with red-brown, purple, or black splotches and scrawls, especially on the large end. Clutches of 3–4 eggs predominate (range 2 to 5).
Incubation - Clutches take 12–14 d.
Fledging - Young are altricial with both sexes feed the nestlings. leaving the nest at 11–14 days of age.
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