Ungulate Ecology Study I-III PR07

PROGRESS REPORT
STATEWIDE WILDLIFE RESEARCH
STATE: Idaho JOB TITLE: Statewide Ungulate Ecology
PROJECT: W-160-R-34
SUBPROJECT: STUDY NAME: Population Performance of
STUDY: I Mule Deer and Elk Populations
JOB: 1
PERIOD COVERED: July 1, 2006 to June 30, 2007
Abstract
POPULATION PERFORMANCE OF MULE DEER AND ELK POPULATIONS
We measured survival and cause-specific mortality of adult female mule deer and elk in Idaho
during 2005-2006 and 2006-2007. Survival of mule deer was similar across both years ranging
from 0.83 in 2005-2006 to 0.86 in 2006-2007. Likewise, cow elk survival was 0.86 in 2005-
2006 and 0.88 in 2006-2007. Predation and hunter harvest were the most common proximate
causes of mortality. Losses to malnutrition we negligible.
Job 1. Survival, Cause-specific Mortality, and Pregnancy Rates of Elk and Mule Deer in
Idaho
Introduction
Mule deer and elk are Idaho’s most important big game animals. Currently, a range of 78,000 to
84,000 hunters participate in Idaho elk hunts and harvest over 16,000 elk, while over 110,000
mule deer hunters harvest 23,000 to 26,000 mule deer. In 2001, deer hunting in Idaho
contributed over $181,000,000 in economic benefits to the state, including nearly 2,000 jobs and
1.3 million dollars in state tax revenues (IAFWA 2002). More than half of all deer hunting in
Idaho is dedicated to mule deer. Elk hunting in Idaho contributes over 150 million dollars to the
state’s economic condition (Cooper and Unsworth 2000).
Mule deer populations in Idaho have followed a trend similar to populations across the western
United States. Mule deer generally achieved high historical densities in the 1950s and 1960s
followed by significant declines across the western states. These declines have been the subject
of intense debates within professional circles (Workman and Low 1976) and among the hunting
public. More recently, populations in Idaho and some surrounding states experienced growth
through the 1980s and a subsequent decline in the 1990s (Compton 2004a). There is little
consensus and, even less definitive evidence, on the causes driving these trends.
Elk populations in Idaho grew steadily into the 1960s and subsequently declined until general,
antlerless hunting was discontinued in 1975. Subsequently, populations grew steadily through
the 1980s. Over much of the more arid habitats of southern Idaho, elk populations grew and
expanded into previously unoccupied habitats. In the late 1980s, calf recruitment began
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