RELATIVE PRECISION AND SOURCES OF BIAS IN PRONGHORN SEX AND AGE COMPOSITION SURVEYS

We compared pronghorn (Antilocapra americana) composition survey estim ates among observers and examined factors that may influence classific ations at 3 sites in Wyoming. We also compared fixed-wing aerial to gr ound survey estimates. Observer disagreement was related to size of pr onghorn group (P < 0.01) during ground surveys. Fixed-wing aerial surv eys yielded significantly lower adult buck ratios than ground surveys in 3 of 6 (P < 0.05) comparisons. Observers' classifications differed in 3 of 12 ground, and 5 of 12 aerial comparisons (P < 0.05) with half the disagreements being fawn ratios. Neither aerial nor ground survey s was consistently more precise. Precision of individual observers was similar at most sites within methods.