USGS Science⌕ Search

Geology topics

Kenneth G. Rice

Publications and source records attributed to Kenneth G. Rice.

23 records · Page 2Linked to original sources
USGS2000

Estimating sighting proportions of American alligator nests during helicopter survey

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 nests (P<0.0001) than did either less experienced or inexperienced observers. Reliable estimates of nest abundance can be derived from aerial counts of alligator nests when corrected by the appropriate sighting proportion.

Proceedings of the Annual Conference of the Southe↗
USGS2000

Determining the size of American alligators using hind-foot track length

Size distribution information is useful for crocodilian management, but can be hard to obtain. Indirect and less costly demographic inferences made from track measurements may be valuable for management decisions. We related hind-foot lengths (HF) with total length (TL) to determine if we could indirectly assess alligator size using track length. Regression showed that HF was an excellent predictor (F1,246= 15722.9, R2=0.98, P<0.01) of TL and track length was an exceptional predictor of HF (F1,14=7520.3, R2= 1.00, P<0.01). The correlation between track length and HF length also was significant (N= 15, r=0.99, P <0.01). Thus, alligator size can be accurately estimated from measures of track length at sites where capture and direct measurement is impractical.

Proceedings of the Annual Conference of the Southe↗