On April 28, 2001, we found an unidentified egg in an artificial nest in Highlands County, FL. The artificial nests used in this study contained one Coturnix japonica (quail) egg and one tethered clay sham egg. The unidentified egg was added to the nest between days 12 and 18 of exposure. The quail egg was unmarked, but the sham was covered in small beak markings suggesting that a bird had manipulated it. Molothrus ater (Brown-headed Cowbirds) and M. bonariensis (Shiny Cowbirds) occur in the area, but Brown-headeds are far more common; however, we never observed either species near this particular artificial nest. An mtDNA sequence (300 base pairs of cytochrome b) amplified from this egg was compared to DNA sequences from GenBank, and we found a nearly perfect sequence match with the Brown-headed Cowbird. Parasitism by these birds in unattended and artificial nests is unusual, especially when host activity is not mimicked by researchers. This is the first record of Brown-headed Cowbird parasitism in Highlands County.