Swallows will soon feast on mosquitoes
It’s spring in Tahoe. As grasses begin to emerge where there were once layers of snow and ice, so do the mosquitoes carrying diseases such as the West Nile virus.
Luckily, along come swallows to take care of the problem.
Swallows – tiny, pointy-winged birds – return to San Juan Capistrano Mission in Southern California almost always on March 19 each year. Although they have a slightly later arrival here at Lake Tahoe, it is just about as predictable, according to Cheryl Millham, executive director and one of the founders of Lake Tahoe Wildlife Care Center in South Lake Tahoe.
“They migrate here in the spring,” said Millham, who has worked at the center for 26 years. “If we don’t have any more bad weather, I’ll probably start seeing swallows in three or four weeks.
“They always start gathering in huge flocks around the end of August and into September and then one day they’re gone.”
Swallows return to Brazil, Paraguay and Argentina for winter, researchers at Cornell University in New York have discovered.
Millham receives calls from residents along the South Shore every spring asking what they can do about the swallows and their nests, which are commonly mistaken for wasps’ nests.
Three types of the birds visit the Lake Tahoe Basin each year, including barn swallows, tree swallows and cliff swallows. Swallows make their nests of mud and need water within close proximity.
While barn and tree swallows make their nests of mud and twigs, it’s the cliff swallows that build their nests entirely of mud, which are usually formed in clusters of 20 or 30 under bridges or eaves of buildings.
Two years ago at Tahoe Keys, residents had complained about swallows’ nests, but once they learned the benefits they decided to put up with the mess, which Millham pointed out is biodegradable and washable.
“Usually, when people learn how good for the environment (swallows) are, then they’re fine with having them stay,” said Millham.
There are at least two reasons for not destroying swallows’ nests, especially during breeding season, according to Millham.
Knocking or spraying them down is illegal. The U.S. Department of Fish and Game states in a report, “In the United States, all swallows are classified under the Migratory Swallow Treaty Act of 1918 as migratory insectivorous birds and are protected.”
In fact, permits are required by Fish and Game just to remove swallow nests.
“During nesting, permits authorizing nest removal are issued only if strong compelling reasons exist,” according to Fish and Game.
“I have known people who have been charged up to $1,000, plus jail time,” said Millham. “When they’re all done, when their babies are gone, they can knock down the nest.”
Swallows, which are capable of consuming up to 1,000 mosquitoes per day during nesting season, can have a health and safety benefit as well, said Millham.
“People should leave them alone because of the West Nile virus,” she said.
The U.S. Center for Disease Control Web site states that the virus, spread by mosquitoes, affects the central nervous system, especially in people over age 50. So far this year, it has been detected in Los Angeles and Orange counties.
Although the disease has been known to lead to death, less than 1 percent of people who are bitten by mosquitoes develop any symptoms of the disease and relatively few mosquitoes actually carry it, according to the Web site.
Information provided by the El Dorado County Health Department said the virus was first detected in New York in 1999, and since has been found in 44 states. A total of 715 illness and 14 deaths were reported in 2003, and 4,000 illnesses and 277 deaths in 2002.
While California has had only two cases reported in humans, four types of mosquitoes that carry the virus live in the Tahoe area, according to the health department.
The public can help prevent the disease from spreading by reporting any crows, ravens, magpies, jays, sparrows and finches that have been dead for 48 hours or less, by calling 877-WNV-BIRD. For more information, check the El Dorado County Web site at co.el-dorado.ca.us.
Once nesting season is over, Millham suggests, in order to prevent future nests, screening can be attached under the eaves. Also, bookshelf brackets can be placed over a window with a board set on top, to keep droppings from hitting the window.
However, for mosquito control in areas near water, nesting structures can be built fairly simply from a post and two pieces of wood. For more information, call the Wildlife Care Center at (530) 577-CARE.
In 2002 Millham and center volunteers cared for 125 swallows and in 2003 they had 66, mostly fledglings which have to be fed every 15 minutes. The center will have volunteer training classes on May 22 and 23.
Millham stressed the importance of swallows in the Tahoe area.
“At the lake here, all people should welcome all the insect-eating animals. The biggest mosquito eaters we have are the swallows and the bats. We need to encourage them, not discourage them,” she said.