Date of this Version
In 1997, the Nebraska Game and Parks Commission began an anuran calling survey using routes following those of the upland game bird surveys. At each stop the observer recorded start and stop times, air temperature, cloud cover, precipitation events, wind speed (Beaufort scale), species heard calling, and the frequency of calls heard. An index of calling frequency was standardized on a scale of 1 (no call overlap) to 3 (full chorus). The number of sites occurring within a species' range (n) was determined based upon the number of sites per survey route and species distribution in Nebraska. A mean call index was calculated based upon the value reported for each species. Thirty-eight routes were completed, of which 17 were surveyed during each of the three sample periods. Thirteen routes were sampled twice and eight were surveyed only once. Thirty-two, 21, 18, and 14 routes were surveyed during April, May, June, and July, respectively. All anuran species known to occur in Nebraska except Gastrophryne olivacea, the Great Plains Narrow Mouth Toad, were recorded during the survey period. Hyla chrysocelis, Acris crepitans, and Pseudacris triseriata were heard most frequently. Spea bombifrons, Bufo cognatus, and Rana caatesbeiana were heard least frequently « 5% of total sites within known range). Buro americanus was heard at four sites along two routes.