Visalia Times-Delta, CA – 14 hours ago
Every year about this time swallows return to the Central Valley. These birds spend winter months in South America, and then as spring draws near they begin a northward migration through Central America and Mexico in order to spend summer months in North America.
The first migrants appear in southern California in late February, arrive like clockwork at the Mission in San Juan Capistrano on March 19 and a few weeks later they’re in the Valley.
Swallows, particularly cliff swallows, often live in close proximity to people. They feed on insects and spend a large part of each day in the air catching flies, beetles, and mosquitoes. Their long, pointed wings give them great speed and maneuverability. The cliff swallow is about 6 inches long and is the only square-tailed swallow in California.
In contrast, the barn swallow is distinguished by its long, deeply forked tail. The cliff swallow is also recognized by its pale, orange-brown rump, white forehead, dark rust-colored throat and steel-blue crown and back.
While enjoyable to watch, cliff swallows nesting in colonies on buildings and other structures can become a nuisance. Their droppings create aesthetic problems, foul machinery and cause potential health hazards by contamination.
Originally these swallows nested on cliffs and walls of canyons. However, structures, such as buildings, bridges, and overpasses, and agricultural activities have increased the number and distribution of suitable nesting sites, so cliff swallow populations have increased. New homes and buildings on the outskirts of town seem to be ready targets.
Cliff swallows arrive at nest colonies in successive waves. A definite homing tendency exists among adults that previously nested at a colony.
These birds are the first to return, followed by adults that bred at other colonies in previous years and by young birds that have not yet bred.
The younger birds may include individuals not born at the selected colony. In addition to their homing tendency, breeding swallows are attracted to old nests, which are durable and often used in successive years. Old nests are usually claimed on the first day of arrival, although probably not by the original makers. Dilapidated nests are quickly occupied and repaired.
Swallows are protected by state and federal regulations under the Migratory Bird Treaty Act of 1918.
As a result, certain activities affecting swallows are subject to legal restrictions. The California Department of Fish and Game, the enforcement agency, considers Feb. 15 to Sept. 1 to be the swallow nesting season.
Completed nests during this breeding season cannot be touched without a permit from the U.S. Fish and Wildlife Service. During nesting, a permit authorizing nest removal will be issued only if it can be justified by strong, compelling reasons.
For example, such justification might include a health or safety hazard posed by a nesting colony situated over an entrance, near a loading area of a warehouse or a food processing facility or at an airport if aircraft and maintenance safety are impaired, but not necessarily a person’s home. Therefore, actions to solve problems with swallows should be started as soon as they are identified and before nests are completed.
Protected birds
Cliff swallows are colonial and numbers of nesting birds increases significantly each year. There are no chemical toxicants registered for cliff swallow control and shooting, trapping or harming swallows is not permitted. Therefore, they are best managed by nest removal and exclusion techniques. Nests under construction may be washed down with water or knocked down with a pole.
During nest building, nest removal will require many days of efforts because cliff swallows persistently rebuild nests for most of the breeding season. My experience is that washing down nests two-to-three-times per day for a week will usually discourage the nesting urge and the use of mylar strips, owls and other deterrent devices can be somewhat effective. The drive to nest is very strong and swallows are very persistent, so deterrents usually are not effective during early nesting.
Once nests have been established, exclusion may be the only recourse. Exclusion refers to any control method that denies physical access to the nest site area. Exclusion represents a relatively permanent, long-term solution to the problem.
In California, a permit is not required for this method, if it is done before the birds arrive, during nest building when there are no eggs or young in the nest or after the birds have left for the winter. If swallows have eggs or young in the nest, exclusion may not be used without a permit.
Netting can provide a physical barrier between the birds and the nest site. The mesh size should be 1/2 to 1-inch. Pull netting taut and prevent it from flapping in the wind. The net should not have any loose pockets or wrinkles that could trap and entangle birds.
Some report that hanging a curtain of netting from the eave will prevent nesting. The curtain should be 3 to 4 inches from the wall and extend down from the eave 18 inches or more.
For more information about these birds visit our website at http://cetulare.ucdavis.edu/ and click on Swallows.
Jim Sullins is a University of California Master Gardener. The Master Gardener column appears Thursdays. To contact the Tulare-Kings Master Gardener Program, phone 685-3309, Ext. 225, e-mail cetulare@ucdavis.edu or write to 4437 S. Laspina, Suite B, Tulare, Ca., 93274.
