The American Oystercatcher (Haematopus palliatus) is listed as a Species of High Concern in the United States Shorebird Conservation Plan due to a small population size and threats during its annual cycle. Previous studies of the American Oystercatcher have focused on Atlantic Coast populations; however, little is known about the reproductive success of the western Gulf Coast population. The objective of this study was to determine nest and brood survival of American Oystercatchers in Texas. A total of 337 nests and 121 broods were monitored on the Texas Gulf Coast during 2011–2013. The top model for nest survival in Program MARK included a linear decline in survival across the nesting season and as nests aged. Survival also declined as island size and foraging habitat near the nest site increased. The probability of a nest surviving from mean initiation date to hatching was 0.384 (95% CI = 0.317, 0.451). The top model for brood survival included a linear decline in survival across the season and an increase in survival as broods aged. Brood survival also varied among years and coastal region. The probability of a brood surviving from mean hatch date to 35 days after hatch ranged from 0.397 (95% CI = 0.204, 0.578) in 2013 to 0.887 (95% CI = 0.673, 0.964) in 2011 across all regions. Known causes of nest and brood loss included beach overwash, depredation, and starvation. This study provides the first estimates of nest and brood survival of the American Oystercatcher along the western Gulf Coast. The additional insight into patterns of nest and brood survival in this species will be useful for future conservation planning efforts that target breeding American Oystercatchers.
Vol. 37 • No. 4
Vol. 37 • No. 4