The impact of anthropogenically-caused salinization on wildlife is a conservation issue of global concern. Increasing salinization of inland wetlands is especially problematic for breeding and migrating birds. In the arid American west, inland wetlands are centers of avian biodiversity, providing habitat for millions of birds. We experimentally examined the effects of different salinity levels on the growth, health and behavior of American Avocets (Recurvirostra americana) chicks. Birds raised in highly saline conditions exhibited significant changes in behavior, including increased activity and decreased feeding and preening. High salinity resulted in significant weight loss of 4.4 g by day 3. Blood measures of chick health indicated that hypersaline-raised chicks suffered from dehydration (e.g., osmolality of chicks reared in brackish water was 305, compared with 381 among chicks reared in hypersaline water). Results of this study, and similar studies on ducks, geese and egrets, indicate that waterbirds in general suffer adverse effects when living in highly saline environments, without access to freshwater. We recommend that water managers ensure the maintenance of freshwater inflows to wetlands throughout the breeding season.