BREEDING BIOLOGY OF AN INTERIOR LEAST TERN (STERNA ANTILLARUM ATHALASSOS) COLONY IN CHILDRESS COUNTY OF NORTH TEXAS

摘要

This study documented nest success, nest initiation chronology and nest site selection for interior least terns (Sterna antillarum athalassos) along the Prairie Dog Town Fork of the Red River in Childress County, Texas during 1998. Terns experienced a 65% nest success rate (Mayfield estimate 71%) and clutch sizes ranged from 1 - 3 eggs (x = 2.25) for 20 nests. Seventy percent of all nests were initiated during the first 20 days of June, which coincided with the highest number of adult terns observed on the study site. All nests were found on gravel/sand bars in the river basin; 25% were placed on gravel and 75% were placed on sand. Sixty-five percent of tern nests were located within 15 cm of driftwood and/or rocks, but nests were not more frequently associated with objects than random sites (P > 0.05). Nests were generally > 10 m from vegetative cover and 200 m from surface water. However, habitat variables (i.e., distances to upland, mudflat, water and vegetative cover) did not vary (P > 0.05) between nests and random sites nor between successful and nonsuccessful nests. This colony of interior least terns was last documented in the mid 1980s and evidently has some degree of stability. Conservation efforts should focus on protecting, restoring and enhancing riparian wetland habitats in the High and Rolling Plains of Texas for this endangered species.