Forest fragmentation in North America concerns many biologists because of its effects on wildlife populations. One group that has demonstrated particular sensitivity is Neotropical migrant birds. We studied Ovenbirds (Seiurus aurocapillus) in forest fragments in a suburban landscape in eastern Massachusetts to determine effects of cowbird parasitism on Ovenbird reproductive success. Our three large (120–312 ha) and six small (10–59 ha) forests were all smaller than most of those studied by other researchers, and they were surrounded by wooded suburban lots rather than agricultural land. Twenty-nine percent of nests found were parasitized by cowbirds; that frequency is lower than other investigators have reported for small, isolated fragments. The number of Ovenbirds fledged in successful parasitized (x̄ = 2.4) and unparasitized (x̄ = 3.8) nests was similar to other studies. Cowbirds were found to remain in nests for one to two days after their Ovenbird nestmates fledged. Differences in parasitism rate between this and other Ovenbird studies may be related to landscape characteristics. Ovenbirds nesting in small fragments in relatively wooded landscapes, as was the case in this study, have higher reproductive success than do Ovenbirds nesting in similar-sized fragments within an agricultural landscape. Using Ovenbirds as a model for neotropical migrants, we suggest that small fragments in a landscape with relatively wooded connections between forested areas may allow migrants to attain higher reproductive success than similar sized forests surrounded by agricultural land.