UTILITY OF 10-DAY CENSUSES TO ESTIMATE POPULATION-SIZE OF BLUNT-NOSEDLEOPARD LIZARDS

The blunt-nosed leopard lizard, Gambelia sila, is an endangered specie s that increasingly is losing habitat within its range in the San Joaq uin Valley of California, Determining local population size of this sp ecies sometimes is necessary far its conservation. Measuring populatio n size from short-duration censuses can save time and money compared t o total counts or mark-recapture methods, but the census must be shown to be accurate. From 1990 to 1994, we completed full-season censuses of blunt-nosed leopard lizards that were marked and recaptured on two plots on the Elkhorn Plain, California. We compared estimates of popul ation size from full-season censuses (considered a true estimate of ab undance) to 10-day counts of the adult/yearling cohort (active April-J uly) and hatchling cohort (active July-October). We found that 10-day censuses can be used to accurately index population size of blunt-nose d leopard lizards, at least in foothill habitat.