thumbnail

Survey of Ungulate Abundance on Santa Rosa Island, Channel Islands National Park, California, March 2009

Open-File Report 2009-1243

By:
, , , and

Links

Abstract

Reliable estimates of elk (Cervus elaphus) and deer (Odocoileus hemionus) abundance on Santa Rosa Island, Channel Islands National Park, California, are required to assess the success of management actions directed at these species. We conducted a double-observer aerial survey of elk on a large portion of Santa Rosa Island on March 19, 2009. All four persons on the helicopter were treated as observers. We used two analytical approaches: (1) with three capture occasions corresponding to three possible observers, pooling the observations from the two rear-seat observers, and (2) with four capture occasions treating each observer separately. Approach 1 resulted in an estimate of 483 elk in the survey zone with a 95-percent confidence interval of 479 to 524 elk. Approach 2 resulted in an estimate of 489 elk in the survey zone with a 95-percent confidence interval of 471 to 535 elk. Approximately 5 percent of the elk groups that were estimated to have been present in the survey area were not seen by any observer. Fog prevented us from collecting double-observer observations for deer as intended on March 20. However, we did count 434 deer during the double-observer counts of elk on March 19. Both the calculated number of elk and the observed number of deer are minimal estimates of numbers of each ungulate species on Santa Rosa Island as weather conditions precluded us from surveying the entire island.

Study Area

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Survey of Ungulate Abundance on Santa Rosa Island, Channel Islands National Park, California, March 2009
Series title:
Open-File Report
Series number:
2009-1243
Edition:
-
Year Published:
2009
Language:
ENGLISH
Publisher:
U.S. Geological Survey
Contributing office(s):
Northern Rocky Mountain Science Center
Description:
vi, 24 p.
Time Range Start:
2009-03-19
Time Range End:
2009-03-19
Online Only (Y/N):
Y