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Red-winged blackbirds (RWBL) and common grackles (COGR) are the two most abundant blackbird species on the continent; Brewer's blackbirds (BRBL) are a much less common, but closely related species, and along with European starlings (EUST), they are two of the most common groups of birds in North America, with combined populations that reach into the several hundreds of millions and make up a significant portion of the avian population (Yasukawa and Searcy 1995). Although the most common bird on the continent, certain regions have seen declines in RWBL for a number of decades. In Ohio and North Dakota, this has been attributed to certain agricultural practices (Blackwell and Dolbeer 2001). Population sizes of a closely related species, the Rusty blackbird have also been on the decline for some time due largely to habitat loss, while populations of COGR, BRBL, and EUST are either stable or increasing.