EARLY NESTING BY THE AMERICAN GOLDFINCH, CARDUELIS-TRISTIS, AND SUBSEQUENT PARASITISM BY THE BROWN-HEADED COWBIRD, MOLOTHRUS-ATER, IN ONTARIO

An American Goldfinch, Carduelis tristis, nest was found on 27 May 199 1 at Guelph, Ontario. The nest was lined with pappus from the Bull Thi stle, Cirsium vulgare, probably obtained from last year's seed heads t hat survived over the winter, as well as a variety of other plant down s. Early completion of the prealternate moult of the female may have b een a factor in stimulating early nesting and egg laying. Although the nest was parasitized by a Brown-headed Cowbird, Molothrus ater, the c owbird chick failed to survive. This was probably a result of the high ly granivorous diet normally fed to American Goldfinch nestlings.