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Cliff Swallows - They are birds you learn to either love or hate
Cliff Swallow identification and ecology They are best identified by their dark heads and white foreheads, dark rusty necks and throats, dark wings and back, light breast, and dark tail with a light rusty rump patch. Another interesting characteristic of the Cliff Swallow is they build gourd-shaped mud nests on cliffs and other substrates, and nest in colonies ranging from dozens to several hundred individual nests. Cliff Swallows originally nested on cliffs or escarpments, but in recent times have also adapted to building their nests under bridges and culverts and all types of buildings, ranging from houses and cabins to barns and office buildings. Often they select tall structures, particularly with overhangs, that give the nest area shade from the sun. This is an important point, since these nests can get overheated, causing death of the young through heat prostration, ectoparasite loading or deterioration of the mud substrate. Cliff Swallows are classified as neotropical migrants - in other words, during the boreal winter they migrate to the New World tropics, namely a vast area in South America stretching from Brazil to Argentina. Because they are migrant birds, they are protected by law under the Migratory Bird Treaty Act of 1918. Special provisions under the law carefully outline the legal definition of the word "take" to include harass, molest, injure, kill, destroy, or capture individual birds, nests or eggs. Most Cliff Swallows arrive in Montana in early May and leave by mid-September, with birds at higher elevations arriving later and leaving earlier than low-elevation colonies. One of the keys to their existence is an overabundant food source solely in the form of aerial insect life. In addition, timing of the nesting season is also based on the monsoon season, when there is a source of mud puddles and wet mud critical for nest construction. When the circular entrance or tunnel of the nest is completed, it is usually a sign the birds have laid their eggs and are getting down to serious nesting.
Conflict between Cliff Swallows and people People also get annoyed by the swallows persistence to nest. The best rule of thumb to eliminate Cliff Swallow/human conflicts is through prevention. Prevention in this case means changing the design of the building or incorporating materials that won't allow mud nests to adhere to the sides of buildings. Metal siding at the juncture of the soffit and the wall can prevent swallows from nesting. Do not use goo-gunk type substances on the walls - they actually get on the feathers of the bird and prevent it from ever flying again. Plexiglass also works in some cases to discourage swallows to nest, because it provides a slick surface. Commercial plastic owls work for about a week, but soon lose their effectiveness when the birds learn the owl is fake and then start defecating on the decoy. Hanging ribbons, chimes, and commercial bird netting are other alternatives. Commercial bird netting is available that can be applied to building surfaces, thus discouraging swallow use. The best approach is to use the netting as a last resort and use it sparingly, because if netting is over-applied swallows can and will nest on it, in which case the program turns into total failure. For best results - and again, as a last resort - apply three foot-long sheets of netting approximately six inches off the wall, and let it blow freely in the wind. Another important consideration is to always allow the birds a "sacrifice area" where you will allow them to nest. This can mean the same building or other buildings on the property where they will not bother anyone. If this does not happen, eventually the entire program will backfire and the swallows can overtake an area. Some people wash down Cliff Swallow nests with a garden hose to discourage them from nesting. Although this may seem like the best solution, it can actually lead to disaster. First of all, it is labor intensive, and be prepared to wash down nests for at least a month or so. Secondly, if the nests fall to the ground, you have increased your chances of the swallow bug entering your buildings. Therefore my rule of thumb is this: If the nest tunnel is completed, do not knock down the nests - for the swallow bugs are housed in the mud, and knocking down the nests only complicates the issue. Leave the nests alone and let the young fledge. Then in the fall take down the nests, using a dust pan to remove them, scoop the mud nest material into a plastic bag, and tie a a knot on the bag to seal it.
Cliff Swallow benefits But also you need to be realistic. Remember, as the West Nile Virus comes on the scene in Montana, these swallows offer benefits to humans, such as consuming large quantities of insects like mosquitoes. If you have ever seen what West Nile Virus has done to humans and understand what a debilitating disease it can be, I think you will realize the importance of having Cliff Swallows around. The key here is not to get rid of the swallows but to encourage them to build their circular mud nests in areas where they can be tolerated. Now that the reader has a better understanding of Cliff Swallow identification, ecology, and prevention, the next Big Sky Birding topic will be Rock Pigeons, formerly called Rock Doves. Rock Pigeon identification, ecology and prevention will be the theme of the November issue of Montana Best Times. Enjoy! And the Best of Big Sky Birding to you!
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