The Outside Story: For deer herd data, states count on hunters
The measure of a successful hunt depends on whom you ask; hunters are often biased by individual success or failure, whereas biologists take a detached, big-picture view. But this much is true: One of the world's oldest occupations is managed today by one of its newest — information technology. And good, hunter-generated data are essential to sustaining the rich deer hunting tradition in both New Hampshire and Vermont.
According to New Hampshire deer team leader Dan Bergeron, preliminary figures indicate that 11,464 deer were harvested in the state in 2014. That's an 8 percent drop from last year but the ninth largest harvest since record-keeping began in 1922. Roughly 40 percent of the harvest was antlerless deer (does and button bucks). In Vermont, deer team leader Adam Murkowski reported 13,590 deer harvested — a drop from 2013 but in line with the three-year average. Antlerless deer made up 41 percent of the total harvest.
Hunters are vital when it comes to modeling and managing the herd, Murkowski said. The law requires that every deer killed be registered at an official check station. In both states, digital information from the harvest helps generate computer models of the living herd by age class — statewide and within smaller management units. In addition, both states' deer biologists examine about one in 10 deer harvested. For these deer, they collect additional measures of age and condition. Vermont pulls a lower incisor tooth and counts growth rings — like tree rings — for accurate aging. New Hampshire takes measures of tooth wear and replacement — a less accurate, but arguably cheaper and faster means of assessment.
Prior to this year's hunt, Vermont's deer herd was estimated to be 135,000 deer. New Hampshire had a pre-hunt population of about 100,000. However, biologists focus less on the overall number of animals, Bergeron said, and more on population trends within management units. For example, in Vermont, last year's winter was severe in some locales; Murkowski explained that the state managed for a rebound in those areas by reducing the number of antlerless permits.
As deer biologists set their long-term objectives, they consider how many deer the available habitat in any given area can support. The aim is a deer herd in balance. Exceed the land's carrying capacity and both the deer herd and hunter success rates will eventually suffer. Less is often more, Murkowsi said. For example, a smaller, healthier deer herd that is growing fast in the younger age classes usually translates to hunters being able to take more antlered deer. Both Bergeron and Murkowski would rather see small fluctuations in deer numbers rather than big population swings.
As for measures of deer health, antlers hold valuable clues. While both states take multiple measurements of the antler rack at all ages, yearling antler growth has proven to be one of the best indicators of an area's carrying capacity. The primary job of yearling deer, Bergeron explained, is to put on weight to survive winter. Antler growth is a luxury. Poor antler development tells you there may be more deer than the habitat can carry. Biologists might increase antlerless deer permits in those areas of the state.
There are other measures that guide management decisions. Certain male to female ratios are known to increase, decrease, or hold a population steady. Browse surveys, deer yard censuses, road kill tallies of lactating does, and hunter-deer encounter surveys all factor into the math of a well-designed hunt.
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