Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable
Comments: HABITAT LOSS: Primarily threatened by habitat loss due to coastal development, dredging operations, and hydrological alterations (Muehter 1998, Paul 1991, Paul 1996). Nesting areas are being lost to habitat conversion for cattle grazing on some islands and the harvest of mangroves for charcoal. PESTICIDES/POLLUTION: Pesticides have been implicated in a decline of a Texas population during the early 1960s. Eggs collected in the 1970s were 6.3 percent thinner than eggs collected prior to 1943, possibly a result of DDT or PCB contamination. In addition, lead intoxication may have contributed to death of a nestling in Florida (Spalding et al. 1997). HUMAN DISTURBANCE: Nearly extirpated from the United States in the late 1800s and early 1900s by the plume trade. Now, disturbance to foraging and nesting birds from increased human recreational activities in coastal habitats is a serious problem. Illegal subsistence hunting threatens some populations. PREDATION: Bald eagles (Haliaeetus leucocephalus) are known to prey on both juveniles and adults. Black vultures (Coragyps atratus) prey upon the eggs and nestlings, laughing gulls (Larus atricilla) eat the eggs, and fire ants (Solenopsis spp.) eat the young in ground nests (Bent 1926, McMurray 1971). Boat-tailed grackles (CASSIDIX MEXICANUS) will break the eggs, but have not been observed consuming the contents (McMurray 1971). Raccoons (Procyon lotor) are probably the most serious predator of wading bird colonies along the Gulf coast. Potential predators include fish crows (Corvus ossifragus), American crows (C. BRACHYRHYNCHOS), coyotes (Canis latrans), and domestic dogs (Paul 1991, Paul 1996). PARASITES: Known parasites include larval ticks (ORNITHODOROS CAPENSIS) found on nestlings in a ground colony in Texas, and 21 species of ecto- and endoparasites isolated by necropsy and examination of regurgitated food taken from Texas and Florida birds. Birds have also been found with Salmonella and avian pox infections (Conti et al. 1986).