H. Franklin Percival

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...

Chlorinated hydrocarbon insecticides have been the subject of considerable controversy. DDT, the most controversial insecticide, and other chlorinated hydrocarbons have been used extensively until recently when their uses were altered by state and federal legislative and judicial actions. The use of these materials has declined but the problem of environmental pollution still exists because of the persistence and ubiquity of these "hard" pesticides. Insecticides have been implicated as being the causative factor in the decline of some predatory bird populations. The concern herein is not...