American Alligator Nesting Ecology in Impounded Marsh Habitat, Louisiana.

The goal was to monitor a large number of female alligators over a 3-year period to obtain information on alligator nesting ecology. This dissertation, although designed to estimate annual nesting rates, provides additional meaningful information on methods of capture, tag retention rates, nest spacing patterns, segregation of size classes, nest site fidelity, the relationship between attendance and nest success, the effects of fire ants on alligator nest success, the relationship between hatchling alligators and their mother, and hatchling dispersal. Passive integrated transponder (PIT), monel web, and cranial mounted reflector tags were evaluated for marking and identifying alligators. Use of harmonic radar for relocating marked alligators was tested. A total of 368 adult and 2,674 hatchling alligators were captured and individually marked between May, 1997 and October, 1999. Methods describe innovative techniques for capturing adult alligators from dens and with baited fines. A total of 378 nests were located. Nest locations were clustered and clusters were not stationary among years. Females of the largest size class nested together away from the marsh edge. Approximately 66% of nests found without eggs were not paired with nests with eggs. The percent of alligators nesting annually ranged from an estimated 6.34% to 15.60%. Average nest site reuse was 3.7%. There were no cases of reuse at a previous nest site by the same female. Fire ants negatively affect alligator nest success by possibly killing hatchlings in the nest, and deterring the opening of nests by the maternal alligator. Attendance by the female alligator did not have an effect on nest success until it was time for the nest to be opened. A field experiment also demonstrated that ants reduce alligator nest success, and that adult activity prior to hatch was unaffected by fire ant presence. Hatchlings alligators that successfully escaped the nest started moving and mixing with other pods within days after hatch. Newly released hatchlings moved distances up to 1,000 m from the natal nest site. Hatchlings appeared to move both as individuals and groups. Some hatchlings may disperse immediately after hatch and require no parental care