Archive for September 26th, 2006
nps.gov
Swallows of the family Hirundinidae are small, adept aerialists with long, pointed wings and deeply forked tails. Although their bills are short, their mouths are wide for capturing flying insects. Overall, swallows resemble swifts but have stronger, more fluid flight. Highly gregarious, they form large flocks and may be seen perched in long rows along branches or wires. Three species of swallows occur in Yukon-Charley Rivers National Preserve; Violet-green, Tree and Bank Swallows. Violet-green Swallows are named for their beautiful, iridescent plumage. Their genus name, Tachycineta, means “fast-moving” and refers to their rapid flight.Descriptions: Violet-green Swallows are common in montane, coniferous-deciduous woodlands. They were also found above treeline in sedimentary rock formations that provided nesting cavities within Yukon-Charley Rivers National Preserve. As their name implies, these small, 13cm swallows are vibrant emerald and violet above with bright, white underparts. Very short-tailed, their wingtips project well beyond the tips of their tails. Confused only with the Tree Swallow, the Violet-green Swallow may be distinguished by the large, white flank patches extending over the sides of the rump and white cheek patches extending over the eyes. Juveniles are gray-brown above, mottled-white below and lack the white extending above the eyes in the adults.
Vocalizations: The song of the Violet-green Swallow is a creaking “teer, twee, tsip, tsip, tsip.” Their calls are harsher “chilp” or “chil-lip” notes. When alarmed, the call is a clear and descending series of repeated “seer” or “teewp” notes.
Nests: Violet-green Swallows nest in tree-cavities, snags, rock crevices or nest boxes. These swallows nest singly and compete for nest cavities with other species. Nests are woven of grasses and lined with feathers. A clutch consists of 4-6, 19mm, white and unmarked eggs. The female alone incubates the clutch for 13-14 days and young birds fledge in another 16-24 days. Both parents care for the offspring.
Diet: The diet of the Violet-green Swallow is composed of insects. These birds are elegant fliers and dart to catch flying insects in aerial pursuit.
Distribution: At the end of the summer, Violet-green Swallows aggregate in enormous, pre-migratory, communal roosts of up to 100,000 birds! Often, they form mixed flocks with Tree Swallows. They winter in South America and Honduras. In summer, they range throughout central and southern Alaska and Yukon, and southward along the Pacific Coast to Mexico. Within Yukon-Charley Rivers National Preserve, these birds were detected in just two ecological units during the Yukon-Charley Rivers National Preserve Bird Inventory, June 1999 and 2000. Only two Violet-green Swallows were encountered in the forests of the Ogilvie Foothills (OF) and the Tintina Hills (TH) ecological units. Violet-green Swallows are expected to be more numerous in the Preserve, but swallow species in general were not well inventoried using our survey technique.
September 26th, 2006
birdbusters.com
Swallow Identification
Cliff swallows and barn swallows are slender, sleek birds that spend their spring and summers in North America. Swallows are very territorial and will return to the same nesting site over and over. Building eaves and other structures often replace cliffs these days to build their distinctive mud pellet nests (see photo at right). Swallows have brownish red faces and throats with steel blue coats and light colored bellies. Cliff swallows have squared off tails, but barn swallows have long forked tails (see top photo). Young swallows have similar coloring, but lighter.
Damage Caused by Swallows
Swallows are often a nuisance in suburban areas as they build their mud nests that damage and deface the outer walls and eaves of residences and office buildings. Swallow feces often end up on the sides of buildings and the ground below from the colony of birds in residence. Building owners report extra clean up costs and concern over slip and fall liability from swallow dropping buildup, plus an unclean, dirty company image. The bacteria, fungal agents and parasites found in swallow droppings and nests can carry a host of serious diseases, including histoplasmosis, encephalitis, salmonella, meningitis, toxoplasmosis and more.
Swallow Control
These small, nimble birds enjoy special legal protection. Once they have laid their eggs in the nest, you CANNOT disturb them. You must wait until they leave for their winter homes to remove the nests and then exclude them using 3/4 inch bird netting installed along the underside of the eaves at an angle to prevent them from building their nests there the following year. Another option is to install several strands of bird wire under the eaves in a strategic pattern to prevent nest buildout. Installation should be completed by a professional bird consultant. Call our offices for more information.
September 26th, 2006
coveside.com
The Tree Swallow (Trachycineta bicolor) is common in any wooded habitat near lakes, streams or marshes. They nest in holes in dead trees, fence posts, eaves, and nesting boxes. The slender Tree Swallow is wonderful at aerial stunts, swooping and diving to catch flying insects. Their reputation for catching mosquitoes far exceeds reality, as they generally retire about the time of day when mosquitoes are abundant.
Their dark blue-green top and pure white underside distinguishes them. Males and females look quite alike.
They spend spring in all but the southernmost states and migrate to the Gulf coast and Mexico for winter. Migrating flocks may number in the thousands.
Tree Swallows take readily to nesting boxes placed out in the open in rural or suburban areas, and they are quite comfortable around people. Once you have them nesting on your property, you may find their population increasing if you put up more boxes each year, as they tend to return to the same spots each year, especially if insects are abundant. Tree swallows like to line their nests with grass and feathers. If you have access to chicken feathers or others, leave some around the nesting boxes, and the swallows will use them.
Prolonged periods of cold, rainy weather will inhibit the Tree Swallows’ ability to catch insects, and the adults may travel a distance to find some. Unfortunately, this sometimes leaves the young too long without food, and they perish. But this will not keep them from returning to start a new nesting They lay 5 to 6 pure white eggs and generally raise one brood each year, which is cared for by both parents.Â
Tree Swallows feed on bayberries in the winter, allowing them to winter father north than other swallows. They are also among the first to migrate north in the spring.
Tree Swallows like playing with feathers, and can frequently be seen tossing one into the air and catching it, or chasing another swallow with a feather.
Tree Swallows will tolerate fairly close neighbors of their own kind. Nesting boxes may be placed as close as 30 feet apart, or even on the same tree. They should be mounted on posts or trees out in the open, near water. It is even acceptable to place the post in water.
Tree Swallows are good neighbors for Eastern Bluebirds and will even help to defend the less aggressive bluebird against its competitors. They like the same size nesting box, so placing two houses near each other, or even back-to-back on a post, will encourage Tree Swallows to occupy one and bluebirds the other. Otherwise, the more aggressive swallows will often use a bluebird house at the expense of the bluebirds.
September 26th, 2006