The female Red-winged Blackbird builds a tightly woven cup nest of long
leaves around upright vegetation located in a swamp, marsh, or wet meadow
over or near water. The nest, completed in 3 to 6 days, is a deep cup of
woven long leaves tightly bound to upright vegetation and lined with fine
From 3 to 5 pale blue eggs scrawled with darker markings are incubated by
the female and hatch in 10-12 days. Chicks leave the nest in another 10 days
or so before they can fly, and climb around in the vegetation. If they fall
into the water they can swim, but are vulnerable and sometimes taken by
predators such as bullfrogs, water snakes, or snapping turtles.
The male is polygamous, and will mate with several females in his
territory. Up to two broods can be fledged by a female in a breeding season.
These birds have been the subject of much research, and many insights
into breeding behavior have been gleaned from this species. One finding is
that young females fledge more daughters than sons, but older females fledge
more sons than daughters. Middle aged birds fledge about the same numbers of
females and males.
The reasons for these sex ratio differences in broods are not clear, but
this is undoubtedly related to the polygamous breeding strategy that
requires more females than males in the population. Younger females are more
likely to survive one or more breeding seasons, and would contribute to the
overall population by fledging females in their early breeding efforts.
Older females, on the other hand, would contribute more to the overall
population sex ratios by fledging males.
Conservation Status and Economic Importance
Banding studies show that populations are short distance
migrants that may return to the same colony year after year. Individual
birds can live more than 14 years in the wild.
Populations are doing well, and these birds provide a
service to mankind by consuming vast numbers of insect pests.
Since these birds consume vast numbers of insect pests,
their presence is welcome. Their willingness to breed even in small wetland
habitats argues for protecting even the smallest seales and other wetland
If you should recover a banded Red-winged Blackbird, please
report the band number to the Bird Banding Lab by calling 1-800-327-BAND.
Alderfer, J. Ed. 2006. National Geographic Complete Birds of North
America. National Geographic Society, Washington, DC. 664 Pp.
Baicich, P. J. and C. J. O. Harrison. 1997. A Guide to the Nests, Eggs,
and Nestlings of North American Birds, 2nd Edition. Academic Press, NY. 347
De La Pena, R. and M. Rumboll. 1998. Birds of Southern South America and
Antarctica. Princeton University Press, Princeton, NJ. 304 Pp.
Gill, F. 1995. Ornithology. 2nd Edition. W. H. Freeman & Co., New York,
NY. 766 Pp.
Terres, J. K. 1995. The Audubon Society Encyclopedia of North American
Birds. Wings Books, NY. 1,109 Pp.
Back to Top | Back to Bird
All images are courtesy of CWBO. All image copyrights are owned by CWBO.
Any use of these images must have permission of CWBO.