Beavers in the ‘burbs?
Many people think of beavers as wilderness animals. They do live in wilderness areas, but also seem comfortably at home in northern Virginia.
Two places in the Mount Vernon-Lee area where you might see beavers are Huntley Meadows Park and the Dyke Marsh Wildlife Preserve.
Recently, beavers have been very visible in Huntley Meadows Park, said Park Manager Kevin Munroe. “This may be best time to see them because they’ve decided to build at the beginning of the boardwalk. They are very cooperative at the moment,” he chuckled.
Huntley Meadows Park
In 1977, beavers built a dam across Barnyard Run in the park which created a swamp or non-tidal wetland and flooded the forest. Huntley has at least three lodges, probably more, and three or four major dams, said Munroe. There are 12 to 24 smaller check dams as well, beaver dams that check or stop flowing water.
Beavers create deep water habitat to escape from their predators, Munroe explained recently. In 1993, the beavers stopped maintaining the dam in the central or main wetland and moved to the lower part of the park, but they have never left Huntley Meadows for more than six months. The last survey of beavers in the early 1990s found around 20 to 25 beavers in the park.
Singing their praises, Munroe remarked: “Beavers have more effect on their habitat than almost any other animal outside of humans. Beavers have a very positive effect on watersheds because they create wetlands that provide wildlife habitat, consolidate silt and allow for deep pools during both winter and summer. They reduce erosion by slowing down the water.”
Beavers live in the Dyke Marsh Wildlife Preserve, a freshwater, tidal wetland, but no one knows how many are there. Freshly-chewed trees are evidence of beaver activity.
The large cottonwood on the island opposite the boat mooring has been girdled by beavers. The National Park Service has put chicken wire around this “iconic” tree to protect it from being destroyed, but typically, NPS lets nature take its course.
Beavers have also built a dam and lodge in Dyke Marsh west of the Mount Vernon Parkway, easily viewed from River Towers.
“The lodge is right where it's been for a few years and it looks like the beavers are rebuilding their dam again,” said River Towers resident Mary Jo Detweiler. “There are numerous mallards swimming in it and quacking happily."
Along the shoreline near the Belle Haven Marina mooring area is a strip of beach known by many Dyke Marsh fans as Dead Beaver Beach, a mysterious appellation, presumably named for a deceased beaver found there once.
Beavers (Castor canadensis) are North America’s largest rodents, dark brown mammals with long incisors, short legs, webbed feet and a long, flat, scaly tail. Their front claws are adapted for digging and grasping tree limbs. They are three to four feet long, weigh between 30 to 75 pounds and live six to 11 years. Beavers have one litter a year between April and June and average three to five young.
“The fundamental unit of population is a colony of four to eight related individuals with a home range size of eight acres,” according the Virginia Department of Game and Inland Fisheries (DGIF) website.
Usually active at night and known as “nature’s engineers,” beavers chew down trees to construct dams and lodges in lakes and streams. Beaver dams usually form ponds. They eat primarily herbaceous vegetation, woody and aquatic plants. They store limbs and logs underwater near the lodge for winter.
In Virginia, beavers are found in the northern piedmont, mountains and coastal plain, but between 1911 and 1932, there were no beavers in Virginia because of over-trapping for pelts. In 1932, state game managers “imported” 35 beavers from other states and released them in nine counties. By 1953, the beaver population had recovered enough so that DGIF allowed limited trapping. Today, the state manages them as a game species.
Beavers create new habitats that help other plants and animals. Their dams can slow moving water and allow other wildlife and plants to colonize. Beaver ponds can attract waterfowl, amphibians, reptiles and aquatic insects. The dams can also allow more sediment to collect and cause flooding of roads and other property. Beavers kill trees and the higher water levels they create can kill trees.
Beavers are nomadic, explained Munroe. They can move into an area, raise the water level, then eat almost everything around and flood themselves “out of house and home.” Then they move to another area and repeat the cycle.
“Beavers pose little threat to humans, their property or pets,” according to Fairfax County’s website. The website also has a September report of a woman attacked by a beaver that tested positive for rabies and advises caution when people see any animal acting strangely.
For more information, visit http://www.dgif.virginia.gov/wildlife/information/?s=050069 and http://www.fairfaxcounty.gov/living/animals/wildlife/species/beavers.