Pestgon FactSheet
“ If they fly they die…if they crawl they fall”

CLIFF SWALLOW (Petrochelidon pyrrhonota)

Description:
The cliff swallow is a bird about 5 to 6 inches in length and when not on the nest, is constantly on the fly for insects. They are also recognized by their long pointed wings as they dart about the sky with great speed and maneuverability. Up close they are pale, orange-brown rump, white forehead, dark rust-colored throat, and steel blue crown back and wings. Normally, swallows are not seen on the ground except when collecting mud for their gourd-shaped nests.

Biology:
Cliff Swallows are made famous by the romantic song, “When the Swallows Return to Capistrano”. This happens in the spring. Cliff Swallows feed on insects and spend a large part of time in the air catching flies, gnats, beetles, and mosquitoes. These swallows build mud nests attached to eves and overhangs of buildings and other structures, a habit that sometimes puts them into conflict with building owners and commercial property managers. This is particularly true when the Cliff Swallow decides to build a colony of mud nests, sometimes dozens of mud nests. The nests are cemented with mud to underside of an overhang of buildings, bridges, or other vertical surfaces. Once they start, their habit is to form a dense cluster or colony of gourd-shaped, mud nests.

Economic Impact:
A colony of Cliff Swallows nesting on a commercial building can become a big nuisance adding to the cost of maintenance and sanitation, due to their messy droppings. Pestgon, Inc. has seen where mud nests and droppings have stained the stucco and other surfaces of beautiful commercial buildings, defacing the professional appearance of a building. Cliff swallows are colonial so the number of nesting birds will increase significantly from year to year. Their copious droppings present a potential health hazard. Swallow nests contain mites and insects and swallow bugs (bed bugs) that can enter buildings. The decaying mud nests eventually fall to the ground and can cause harm, particularly if the nests are above a door or walkway. So while there may be something romantic about the swallows returning to Capistrano, when they have attached themselves to your commercial building, they are not just a nuisance but, an economic liability.

Management Methods:
Managing problems with swallows should be started as soon as they appear and are identified. Pestgon, Inc. finds that they are best managed by nest removal and exclusion techniques. Their mud can be washed off or removed prior to nesting, so it is imperative to act quickly upon their arrival. Netting can provide an effective physical barrier between the birds and the nest site. Under the Migratory Bird Treaty Act of 1918, Cliff Swallows are protected by state and federal regulations, as migratory insectivorous birds. During nesting a permit authorizing nest removal can only be issued by the, U.S. Fish and Wildlife Service, and only if it can be justified by strong, compelling reasons such as health or hazard. If eggs or young are in the nest when a permit is requested, the application will probably be denied.

Additional Links:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7482.html