Avian Area Searches on Little Bighorn Battlefield National Monument: 2012 Report

Van Lanen, Nick

The Rocky Mountain Bird Observatory, in conjunction with the US National Park Service, conducted five days of avian area searches covering the full extent of Little Bighorn Battlefield National Monument (LIBI) from 30 May to 3 June, 2012. The goal of the project was to compare data from this survey to previous surveys. A single observer counted the number of individual birds on LIBI while slowly walking transect lines spaced approximately 250m apart. The method of detection and indication of breeding behavior were recorded in addition to the species and number of individuals for each separate observation. In total, 577 individuals of 47 species were detected during the avian area searches. Breeding behavior was confirmed for four species, strong evidence of breeding was observed for eight species, and moderate evidence of breeding was witnessed for an additional eight species. Of the 47 species detected during the 2012 area searches, 10 species had not been previously detected in avian surveys conducted on LIBI by Bock and Bock (2006) in 1985, 1986, and between 2002 and 2006. In contrast, Bock and Bock detected 23 species which were not observed during the 2012 area searches. Some of these species were likely migrating when observed by Bock and Bock and would not be expected to be present during the 2012 survey window. Other species detected by Bock and Bock that were not observed in 2012 are strongly associated with water and are unlikely to regularly occur within the LIBI boundary and/or are unlikely to breed within LIBI at the present time as a result of two fires that reduced sagebrush and shrub cover on both the Reno-Benteen and Custer Battlefields. It is likely that some of the species recorded by Bock and Bock are still present on LIBI but went undetected during the short survey duration in 2012. Results of the 2012 area searches on Little Bighorn Battlefield National Monument were compared to bird detections recorded at point count stations classified as either "grassland" or "riparian" under the Integrated Monitoring of Bird Conservation Regions program within the Montana portion of Bird Conservation Region 17 (BCR 17, Badlands and Prairies). Five of the ten most commonly detected species on LIBI were among the ten most commonly detected species within the Montana portion of BCR17, indicating that the avian community residing within LIBI is fairly representative of that found in the surrounding area. Continued monitoring on LIBI is recommended to assist in informing LIBI managers on the effects of succession, natural disturbance, and the introduction of exotic species on the avian community. Future monitoring efforts which account for incomplete detection of individuals and allow for the production of density and occupancy estimates for species residing within LIBI would likely be more informative to LIBI managers.