We placed predator exclosures around 31 Black Tern (Chlidonias niger) nests in Maine in 2001–2002 to measure growth and survival of chicks. Fifty-four percent of exclosed nests that hatched young were depredated in 2001 and four exclosed nests were abandoned prior to hatch. We modified our exclosure design in 2002 and only one nest (7%) was depredated and no nests were abandoned prior to hatch. Kaplan-Meier estimates of chick survival in the absence of predation were 0.87 to 18 days in 2001 and 0.90 to 15 days in 2002. Mass ratios among first, second, and third-hatched chicks indicated that size hierarchies were present in broods near time of brood completion, but linear growth rates and asymptotic mass were not affected by hatch order in 2- or 3-chick broods. Predation was the primary determinant of chick survival in Black Tern colonies studied and food availability was not limiting chick growth. Predator exclosures did not prevent all depredation, but our exclosure design was effective at protecting and retaining chicks until fledgling age at 70% of nests; the majority of adults readily accepted predator exclosures.