The Role of Reproductive Success in Colony-Site Selection and Abandonment in Black Skimmers (Rynchops niger)

I examined colony-site tenacity and reproductive success in 19 colonies of Black Skimmers (Rynchops niger) for 5 yr in New Jersey. Frequent colony-site shifts occurred, and only two sites were occupied in all 5 yr. Although in one year fledging success was nearly zero due to flood tides, in most years tides destroyed less than 25% of the colonies, while predators destroyed up to 50% of the colonies. Skimmers usually abandoned unsuccessful sites and continued to nest in successful sites. Colony abandonment was greater in colonies subjected to predation pressures than in those subjected to flooding. I suggest that this difference related to the high predictability of future low reproductive success when a colony was destroyed by predators (high probability of future loss) as compared to floods (low predictability).