Did you know that Butte County migratory deer herds have been in decline for several decades? Critical deer herd winter range is generally on south and southwest facing slopes from 3000 feet in elevation down to about 500 feet, especially where the land has not been subdivided into smaller parcels with scattered houses and prioritized fire suppression. A regular interval of low-intensity wildfire is needed for fresh deer browse and biological diversity. It is not the resident herds eating ornamental yard bushes that are threatened. It is the herds that migrate up to 100 miles, twice a year, that are threatened by increased human presence.
In a presentation to the Butte County General Plan Citizens Advisory Council on 2/28/08, Fish & Game Biologist Henri Lomeli reported that the migratory deer herds are being decimated by lung worm disease causing 78% mortality among yearling fawns. Then the few that remain are subject to poaching and being run over by the ever-increasing number of motor vehicles found in the mountain forest and foothill chaparral, especially along their ancient migration routes. The ancient migration routes were used by native Americans following the herds. Those trails became wagon roads, eventually were paved, and now are where many highways are found.
The National Forests have recently been closed to off-road, cross-country, motorized travel to try to stem an incredible proliferation of poorly sited user-created routes, with their consequent adverse impacts to forest resources such as wildlife habitat connectivity, clean water, and quiet recreation. Off highway vehicle routes are being evaluated for inclusion into the Forest road system. There is considerable pressure from ATV and motorcycle users to designate more circular routes just for them, which would further increase an already high road density.
In the Bucks Mountain / Mooretown Deer Herd Management Plan it states "From 1.5 to 6+ acres of habitat are destroyed for each mile (12 to 50+ feet wide) of road construction. Although the road mileage of the range is unknown, it is great enough to account for several thousand acres of land. Vehicular disturbance further reduces habitat utilization. Roads significantly compound the poaching problem by causing easy and widespread access to deer. Road kill can cause a considerable loss (see A.7.c above)." Section A.7.c states in part, "For both herds, a road kill exceeding 34% of the reported buck take is estimated."
Dogs allowed to run loose also take a high toll on migratory deer. The Department of Fish & Game allows free-running dog packs to be shot. Stress from loose dogs chasing them is one of the top 3 factors causing increased deer mortality. Shortening the hunting season would have little effect in preserving migratory deer herds because it is not the bucks that need protection. Current hunting restrictions leave plenty of bucks for breeding.
Ideally, some deer migration routes along sloping SW to NE ridges should have no roads so as to better exclude humans with dogs that scare the migratory deer causing the does and fawns to panic and drown in canals and rivers and use up what little fat reserves they have from browsing sparse winter vegetation. A weak fawn is less likely to survive disease. The North American Mule Deer Conservation Plan recommends, "evaluating road densities to ensure that road densities are not adversely impacting mule deer habitat, particularly fawning areas."
As part of the Butte County General Plan update, Galloway Consulting has used Geographic Information System data to map where the best winter habitat is for migratory deer. Preliminary maps from that effort may now be viewed online by browsing to http://www.buttegeneralplan.net/ebinder/2008/2008-02-28/default.asp then opening and scrolling the Butte County Deer Range document.
Unfortunately the foothills are about 90% private property; and deal deer habitat there is also favored as building sites. The existing parcel size restrictions in critical deer winter range are not the best way to protect deer habitat, but about the only tool Fish & Game has aside from acquiring preserves and conservation easements from willing sellers. This is just one of the reasons why subdivision of the large remaining foothill parcels into many, smaller ranchettes must be discouraged. Human population growth should occur within existing urban boundaries or, if allowed on the remaining large lots of 160 acres or more, be clustered so as to preserve large areas of open space.
