Allan R. Woodward

Hatching success of crocodilian eggs can be influenced by the age of the embryo at time of collection. We conducted an experiment to determine the amount of care necessary during egg collection to optimize embryo survival when alligators eggs at different stages of development were subjected to simulated field conditions of choppy vs. smooth water and cushioned vs. non-cushioned support. We also compared hatching success of rolled vs. non-rolled eggs at different stages of development. We found that transporting eggs in choppy water reduced hatch rates in the absence of cushioning (P <...

Proportions of American alligator (Alligator mississippiensis) nests sighted during aerial survey in Florida were estimated based upon multiple surveys by different observers. We compared sighting proportions across habitats, nesting seasons, and observer experience levels. The mean sighting proportion across all habitats and years was 0.736 (SE=0.024). Survey counts corrected by the mean sighting proportion reliably predicted total nest counts (7?2=0.933). Sighting proportions did not differ by habitat type (P=0.668) or year P=0.328). Experienced observers detected a greater proportion of...

We used mark-resight methods to estimate sighting proportions of American alligators (Alligator mississippiensis) during night-light and aerial helicopter surveys. Alligators ≥122 cm were captured during 5- to 12-day periods on Orange Lake and Lake Woodruff National Wildlife Refuge, Florida, and marked with paint on the dorsal neck area. Replicate helicopter surveys were subsequently flown on each area to record marked and unmarked individuals. Population estimates were calculated and compared with night-light and aerial counts of alligators ≥122 cm. Estimated mean proportion of alligators...

Sixty-eight night surveys of American alligators (Alligator mississippiensis) were conducted from 17 June 1976 to 12 July 1977 on a large cypress-fringed lake in north-central Florida. Multiple regression analyses of the effects of II environmental variables (water temperature, air temperature, wind speed, wave height, cloud cover, water level, moonlight, precipitation, 24-hour precipitation, 24-hour maximum temperature, and 24-hour minimum temperature) on surveys with a white light (n = 44) indicated that counts were positively correlated with water temperature and negatively associated...