MULE DEER FLIGHT REPORT
HUNTING DISTRICT 312
PILOT: Joe Rahn
OBSERVER: Julie Cunningham
DURATION: 2.5 hours
OBJECTIVE: Count and classify mule deer during the spring green-up in the Bridger Mountain
special permit area.
CONDITIONS: We started at 8:00 am under clear skies and ended at 10:30 am. It was a warm
day with temperatures reaching into the 40s. Air conditions were good and winds were very
light. Rain at low elevation Tuesday left a snowline at high elevation, but generally ground was
open and bare at lower elevation and patchy snow up through the highest elevations and north
aspects. Only the earliest green-up conditions were observed. We deliberately flew on the
earliest edge of green-up (before any green flush observed) in keeping with traditional flight
times from the mule deer studies (1970’s-1990’s) and our excellent counts in 2014 under similar
early-greenup conditions. Many mule deer groups were ideed out on the south-facing slopes, but
many were also in the trees and scattered. The lack of snowpack meant mule deer could
distribute through the mountain rather than congregate, perhaps influencing the quality of survey.
Overall survey quality was fair.
COUNTS: The survey was started just south of Ross Creek and ended at Pass Creek. We flew
only about 1-2 miles out onto the agricultural flats and generally 2-3 miles up the canyons –
further in than some years due to the lack of snow.
We counted 223 total deer, with 157 adults and 64 fawns. Although lower than long-term
average, this is still higher than 2010-2013 lows. We saw 25 groups of deer with an average
group size of 9 (down from average group size of 13 in 2014). The fawn-doe ratio of 41 is
higher than the previous 43-year average of 29, but within range of recent variation. The fawn
ratio follows a high post-season ratio of 54 fawns per 100 adults, suggesting a good winter
survival (but note that April and May are key time periods for mortality according to Pac and
Given the above-average fawn ratio in this year it seems illogical to assume population decrease
from the 2014 count, but rather that the difference is due to survey conditions.
As of 2010, we decreased the number of adult doe licenses available from 250 to 100, and raised
mountain lion quotas by 2 (1 additional male, 1 additional female) as of 2012. Statewide
direction resulted in zero mule deer doe licenses issued in 2014. Although no harvest data is yet
available, we may assume little to no hunting-related female mortality from the prior fall.
Buck licenses (currently 75 issued) continue to meet adaptive management criteria. Hunter
success has varied from 14-30% success (2014 results not yet available), age structure was last
around 4.5-5.5 (though we are no longer collecting these data), and the doe:buck ratios of the
post-season counts have varied from 29-53 bucks per 100 does, with a significant proportion of
4-points in the count. Bucks with 160-190 Boone and Crockett Score have been reported.
OTHER WILDLIFE OBSERVATIONS: We also observed 2 elk (more uncounted elk on the
Running Elk Ranch), one grouse, 1 bull moose, and 2 bald eagles on this flight.
Table 1: Bridger mule deer spring counts from 2001 to present
Figure 1: Long-term count and license information for Bridger mule deer. The count occurs on 1 of 4 westside population-habitat units and does not reflect whole-hunting-district counts.
Figure 2: Track route and locations of wildlife seen during the 3/19/15 mule deer flight in the Bridger
mountain census area.