December 30, 2006
Deer Research and Data Use
The 2005-06 deer season marked a change in how the Deer Project
collects yearly deer age and related biological data. With the
introduction of telephone and Internet check-in, check stations were
no longer available to gather needed biological data from deer.
Instead, DNR Wildlife and Heritage staff, along with volunteers,
examined 3,836 deer that were brought to butchers shops across the
state during the first part of the 2-week firearms season.
Like the deer brought to check stations in previous years, deer
examined at the butcher shops were sexed, aged, and antler
measurements were recorded for bucks. Deer were also checked for
evidence of illness or disease.
The yearly sample of harvested deer provides valuable that is used
to estimate deer population numbers and to detect any changes in
deer herd reproductive potential. It is also used to monitor the
overall health of deer and the effects of changes to seasons and bag
limits made to better manage deer populations.
Staff and volunteers determine the age of each deer by the wear and
replacement of its teeth. As young deer get older their milk teeth
are replaced with permanent teeth. As adult deer age, their
permanent teeth begin to wear down. This enables biologists to
reliably categorize deer as fawns (less than 1 year old), yearlings
(approximately 1.5 years old) or adults (2 years and older). The
proportions of deer in each age class and their gender are then used
in reconstruction models to develop and follow trends in the state's
The antler beam circumference measurements of yearling male deer
that are brought to butcher shops are used as indicators of the
reproductive potential and health of the deer herd. Yearling males
in good habitat with moderate deer numbers will weigh more and have
larger antler beam diameters. Abundant food and modest competition
translates into more energy available for antler and body growth.
This is most evident in the yearling age class. Trends in these
measurements can indicate deer herd over-population and habitat
degradation. Overall, Maryland's long-term data for these indicators
show healthy, productive deer populations across the state.
Deer that are checked on opening day are also examined for evidence
of hemorrhagic disease; a viral disease spread by biting midges.
Hemorrhagic disease, or "Blue-tongue", commonly appears in late
summer and early fall. Deer that have survived hemorrhagic disease
and are harvested will exhibit hooves with sloughing or peeling
tissue. These deer are still suitable for human consumption.
Hemorrhagic disease occurs yearly in Maryland, although it varies in
intensity. The results of this statewide examination are reported to
the Southeastern Cooperative Wildlife Disease Study in Athens,
Georgia as part of a nationwide survey. This study is one of the
oldest and most complete nationwide wildlife disease investigations.
Maryland Dept of Natural Resources