Comparative toxicity of seventeen pesticides to the Quelea, house sparrow, and red-winged blackbird.

Ontogeny of hemoglobin in the house sparrow.

SUMMARY A 'switchover' from synthesis of predominantly embryonic hemoglobin to synthesis of predominantly adult hemoglobin occurs during differentiation of the house sparrow. This 'switchover' is demonstrated by a change in electrophoretic pattern generally comparable with that of the chicken, slightly different from those of the duck and man, and, perhaps, dissimilar to that of the red-wing bl...

Decline of the Red-winged Blackbird Population in Ohio Correlated to Changes in Agriculture (1965-1996)

Based on North American Breeding Bird Survey (BBS) data since 1966, Ohio has traditionally hosted 1 of the highest breeding season densities of red-winged blackbirds (Agelnius phoeniceus) of any U.S. state or Canadian province. However, from 1966 through 1996, breeding populations of red-winged blackbirds in Ohio showed a marked decline ( Z % change/yr in birds per route = -3.9), with breeding ...

Territorial Male Red-winged Blackbird Distribution in Wood County, Ohio

Egg yolk layers vary in the concentration of steroid hormones in two avian species.

Maternally derived steroid hormones are known to be present in the yolks of avian eggs; however, the physiological mechanisms involved in their deposition remain largely unexplored. Investigations of steroid production by avian follicles have demonstrated temporal differences in the concentrations of progesterone, 17beta-estradiol, and testosterone during yolk formation. Because yolk is deposit...

Predators on Red-winged Blackbird nests in eastern North Dakota

Predation has consistently been identified as the most common cause of nest failure for Redwinged Blackbirds (Agelaius phoeniceus). During May and June, 2000 and 2001, we used infrared-triggered camera systems to identify potential nest predators on artificially relocated Red-winged Blackbird nests in eastern North Dakota. For some of the species observed, these observations represent the first...