MOOSE TRANSPLANT TO SOUTHWESTERN ONTARIO

Abstract

During December 1991, January 1992 and January 1993 106 moose (Alces alces shirasi) were captured in north central Colorado, northeast Utah and southwest Wyoming and transplanted to the upper Rio Grande river basin in southwestern Colorado. Moose were captured by stalking them on the ground and administering a 2.7mg carfentanil-40mg xylazine mixture from dart guns (n=9), by darting from a helicopter with 5mg carfentanil per animal (n=26) and by nets fired from helicopters (n=71). Both helicopter techniques involved transporting moose by suspending them from lines under the aircraft and flying them to nearby stock trailers. Overall capture related mortality of moose was about 12%. Necropsies were performed on 9 animals. Aspiration of rumen fluid was a factor in the death of four animals drugged from and transported by helicopter. Mortalities associated with the helicopter/net gun technique appeared related to capture myopathy and, in one case, aspiration pneumonia. Moose from north central Colorado were larger and in better physical condition than the Utah and Wyoming animals. Mortality rates for Utah and Wyoming moose (18.2%) and Colorado moose (4%) appeared closely related to the physical condition of moose at the time of capture. Forty-four moose were fitted with radio collars and periodically located after release. After two years the animals occupied an area of approximately 10,000 km². We recommend the helicopter/net gun technique as the most cost effective and least stressful method of capture. We further recommend that transplants be made at times when stress levels are at a minimum for the animals to be captured. We believe early winter is the optimum time.