Rocky Mountain elk survey, Shasta County, California. Final Report FG-8529

FLUCK, WT; SMITH-FLUECK, JM

1989-01-01

1992-12-31

asesoria cientifica-tecnica, recomendaciones

Recursos naturales renovables-Otros

Introduced Rocky Mountain elk (Cervus elaphus nelsoni) were studied in Shasta County between August 1989 and June 1990. The California Department of Fish and Game (DFG) requested that the following parameters of an unstudied subpopulation of elk be evaluated: a) the total number of elk, b) the sex and age composition, c) the seasonal distribution, d) the seasonal habitat utilization, and e) reproductive aspects (the rutting and calving seasons, and reproductive success).    The study of these parameters is inherently difficult depending on habitat structure, animal behavior, and available techniques. Enumerating sex and age ratios, but especially the total number of animals in elk populations is the most difficult task of population assessment. Several methods are available, but the difficulties lie in applying these techniques to specific situations and assessing the reliability of estimates thus obtained. All methods have 2 basic assumptions which must be considered:  1) mortality and recruitment (including movement in and out of the population) during the period of data collection are negligible or, if not, are corrected for in the estimate, and 2) all members of the population have an equal (or known) probability of being counted.    Due to the habitat structure in the study area and the behavior of elk we suggested that a study without the use of radio telemetry would result in unpredictable success. Fortunately, our proposal to use radio telemetry to study this elk herd was accepted by DFG, and at the end of February 1990, 2 adult females were captured and marked with radio transmitters by DFG personnel. As a consequence, observations between August and November 1989 at the beginning of the study period were not based on radio marked animals.    Between August 23, 1989 and February 20, 1990, 74 man-days were spent in the field and 7 elk were observed directly. On February 20 and 21 1990, 2 elk cows were fitted with radio transmitters, and during subsequent 88 man-days, 260 elk were observed directly. The elk hunting season began on September 9 and lasted through September 24, 1989.    The contract with DFG allotted for 108 man-days for this project, and due to additional support from the Mzuri Foundation and Rocky Mountain Elk Foundation, it was possible to use telemetry and extend the monitoring period of the radio-collared elk by another 14 man-days. However, due to extra time spent with capture methods and the subsequent peculiar behavior of the radio-marked elk after their release, we decided to return during May and June and we donated another 40 man-days in order to extend the observation period and produce more meaningful data.