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Deer Program Update

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The DEEP Wildlife Division’s Deer Program has been busy working on several projects over the past few years.

Deer Population Study

An intensive, multi-year research project, which began in fall 2011, will determine fawn production, adult and juvenile survival rates, causes of mortality, and habitat use in northwest Connecticut. Deer Program staff conducted spotlight surveys in Sharon, Salisbury, Cornwall, and Canaan an hour after sunset from the back of a pickup truck on specified routes to determine fawn to doe ratios. Staff observed 0.36 fawns per doe, which was slightly lower than the number reported by hunters during the hunting season (0.40-0.53 fawns per doe).


Biological data have been collected during peak hunting days at check stations since 1975. However, hunters are no longer required to bring deer to a check station. Harvests should be reported via the online reporting system or by telephone.

The following winter (January-April, 2012), 26 adult female deer (15 in Sharon, 9 in Salisbury, and 2 in Cornwall) were captured and equipped with radio-collars, ear tags, and a temperature sensitive vaginal implant transmitter (VIT). Radio-collars were used to locate the adult females several times a week, using a hand-held receiver and antenna, to determine survival and movements. During the first six months of the study, adult survival was 92%. One deer was struck by a motor vehicle within a few days and one died in July of unknown causes.

During the 2012 fawning period (May 23-June 27), 22 fawns were captured and equipped with a radio-collar. Many does gave birth late at night and moved their fawns before morning, making it difficult to locate them. Most does (67%) gave birth to single fawns, 27% gave birth to twins, and one doe gave birth to triplets. Fawns were born as close as 17 yards (avg. = 113 yards) from a road and 26 yards (avg. = 124 yards) from a house. Average birth rate was 1.4 fawns per doe. Average weight of fawns at birth was 7.5 pounds and 68% of fawns were male. A total of 10 fawns died within 90 days of birth. Sources of mortality included natural causes (40%), predation (20%), agricultural practices (20%), and unconfirmed causes (20%). The fawn survival rate through their first summer was 50% (0.67 fawns per doe). It can be expected that a few more fawns will be lost to some source of mortality by the end of their first year. Analysis on deer movements and landscape use of does and fawns will be evaluated in the future, and there are plans to capture additional deer in the winter of 2012-2013.

Chronic Wasting Disease Surveillance


The 4-poster device is a feeding station designed to control ticks on white-tailed deer. As deer feed on bait at the station, treated rollers brush against their neck, head, and ears, applying a tick-killing chemical.

After nine years of chronic wasting disease (CWD) surveillance in Connecticut, funding provided by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service was eliminated from the federal budget. CWD is a degenerative neurological disease that affects cervids, such as deer, elk, and moose. Since Connecticut began CWD surveillance in 2003, nearly 5,000 deer have tested negative. Of greatest concern to Connecticut’s deer population has been the status of CWD in neighboring New York. CWD was first documented in 2005 in seven deer in New York. Over 32,000 deer have been tested in New York, with no additional cases documented. The outlook for the deer population in New York looks good and some previous restrictions related to CWD concerns may be lifted.

Unfortunately, each year CWD is being documented in new states, with the most recent case occurring in a captive cervid facility in Pennsylvania in October 2012. Many of the states where CWD has been documented have large numbers of captive cervid facilities. The movement of captive cervids is believed to be the primary means affecting the spread of CWD from state to state. Concerns with these actions have prompted tighter restrictions on the captive cervid industry and restrictions on the transportation into Connecticut of deer harvested in states where CWD has been documented. Few captive cervid facilities exist in Connecticut, and those that do primarily consist of a few animals. Although a large source of funding for CWD monitoring has been lost, the Deer Program will continue to test deer displaying symptoms associated with CWD, such as emaciation, abnormal behavior, and loss of bodily functions.

Deer Tick Control Study


A total of 22 fawns were captured and equipped with radio collars to determine survival rates, movements, and use of the landscape.

Wildlife Division biologists, along with staff from the Connecticut Agricultural Experiment Station, have been assisting the community of Mason’s Island, in Mystic, in assessing the use of 4-poster devices to reduce tick populations in the small isolated community. Division staff has been collecting ticks at Mason’s Island where the devices are being used and at a control site (Black Point) where no 4-poster devices exist. Over a five-year period (2008-2012), ticks were collected in June at 37 sites at Mason Island and 39 sites at Black Point. At Mason Island, tick density and infection rates declined over a four-year period, although cases of Lyme disease remained similar (infection rates and cases of Lyme disease are not yet available for 2012). In addition to using the 4-poster devices at Mason Island, 61-68% of residents have been using a commercial tickacide application on their properties. A tickacide was also used on open space lands. At Black Point, the control site, tick density essentially remained the same over the five-year period. It appears that the 4-poster devices, in conjunction with commercial tickacide application, have reduced tick density and the percentage of ticks carrying the Lyme disease spirochete. However, the rate of human cases of Lyme disease in the Mason Island community has shown little change.

Biological Data Collection and Analysis

Biological data have been collected by Wildlife Division staff during peak days of the hunting season at select check stations since 1975. Data collected includes sex, age, dressed body weight, number of antler points, and beam diameter of yearling bucks. These data are used to assess the health of Connecticut’s deer herd. An analysis of data shows a healthy deer population with little change in the herd’s health over the last 18 years.

Beginning in 2011, in an effort to explore alternate means of collecting biological data, several questions were added to the online and telephone harvest reporting system that provided greater sample sizes and confidence levels, as well as a variety of data. Sex, age, and antler points can still be determined through this method, along with hunter observation rates. Observation rates are used to determine fawn:doe ratios, buck:doe ratios, and deer observed per hour.

With the advancement and convenience of the online and telephone reporting system, Deer Program staff is able to collect similar and additional data in a more efficient and practical manner, negating the need to continue collecting biological data at deer check stations. Based on responses from hunters on the 2010 hunter survey, most hunters (69%) were in favor of closing check stations if alternative methods were used to collect data on harvested deer. Moving forward, trend information generated from the new system should provide better insight into management of Connecticut’s deer population. Hunters will be allowed to report harvested deer during the entire hunting season, including the first four days of the shotgun-rifle season, via the online and telephone reporting systems, and will not be required to bring their deer to a check station. Check stations will remain open for obtaining replacement tags for deer management zones 11 and 12.

Regulations in red are new this year.

Purple text indicates an important note.

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