Archive for June 20th, 2006
sarep.ucdavis.edu
Article written for Sustainable Agriculture
Chuck Ingels
Farmers and ranchers are looking closely at the benefits barn owls offer as an alternative method of controlling vertebrate pests (see Sustainable Agriculture Vol. 5. No. 1). The diet of the barn owl (Tyto alba) is relatively easy to ascertain, and several dozen studies have been conducted throughout the U.S. to determine the prey species consumed (Clark and Bunck, 1991). Barn owls swallow their prey whole and later regurgitate one to two inch pellets containing undigested bones, teeth, and fur. The owls usually produce one to two pellets per day, often dropping one at their nesting site and one at a distant roosting site (Evans and Emlen, 1947). Skulls found in these pellets can be keyed out to determine the identity of the prey species.
Over 95 percent of the diet usually consists of small mammals (mostly rodents), however in some studies substantial bird remains have been found. According to Colvin (1986), each adult barn owl may consume about one or two rodents per night; a nesting pair and their young can eat over 1,000 rodents per year. Dietary studies from California and other states show that a barn owl consumes an average 50 to 60 grams of prey per day (0.11-0.13 pounds per day, 40-48 pounds per year). The actual species consumed depends on the species abundance and availability in the area.
Overview
Table 1 shows the results of several barn owl prey studies conducted in California. In many studies, meadow voles and/or pocket gophers were consumed most often, while pocket, white-footed, and house mice were also important. One notable species missing in nearly all these studies is the California ground squirrel (Spermophilus beecheyi). This species ventures above ground only during the day, while the barn owl hunts almost strictly at night.
Study Findings
Berkeley 1926-27. Because each of these studies took place in Berkeley and because the results of each were very similar, the percentages of each species were averaged and combined into one column. In one study (Foster, 1926), pellets were collected on one sampling date from under a nest in Wildcat Canyon, just northeast of Berkeley. In another study (Foster, 1927), pellets were collected over a period of one and a half years from a nest located in a cave in Wildcat Canyon. Prey counts were separated by the dry season vs. the wet season. More shrews, Jerusalem crickets, and white-footed and pocket mice were taken during the dry season than the wet season, while the opposite was true for pocket gophers. In a third study (Hall, 1927), accumulated pellets were collected on one sampling date from a location in Berkeley.
San Francisco Bay region (Smith and Hopkins, 1937). In this study, 12 boxes were installed in trees and barns in these counties: Marin (4), Contra Costa (2), Alameda (3), and San Mateo (3). A total of 141 pellets were collected over three years. California meadow voles were found most frequently except in Marin County, where pocket gophers predominated.
Central California (Hawbecker, 1945). Pellets were collected over a wide area during the nesting seasons of several years. Three types of habitat were included in this study, ranging from a well-forested, humid region to one that is treeless and shrubless. The specific regions and important prey findings are as follows:
1. Santa Cruz and western Monterey counties (coastal Transition Zone): pocket gophers-33%, meadow voles-17%, and birds-16%.
2. Eastern Monterey and western San Benito counties (Upper Sonoran zone): pocket gophers-52%, pocket mice-17%.
3. Western Merced and Fresno counties (Lower Sonoran Zone): pocket mice-66%.
Based on rodent trapping in several of the study areas, the barn owl was found to serve as a good sampler of the small mammals of a given area. However, the author noted that the selection of species appeared to be based partially upon numbers and ease of capture.
Davis (Evans and Emlen, 1947). An average of one pellet per day was found beneath a palm tree over a one year period. The palm tree served as a daytime roost to one barn owl. Based on nighttime observations, the owl was determined to have a hunting range of about 165 acres. About 140 acres were in open fields planted largely to grain and alfalfa and 25 were in wooded areas along Putah Creek. Animals typically associated with wooded or brushy cover, including house mice, deer mice (Peromyscus), harvest mice, and roof rats, comprised 57 percent of the total food items. Open field habitats, more than six times as extensive on the owl’s range, contributed the remaining 43 percent of the items, which included pocket gophers and meadow voles. During the fall, the numbers of house and deer mice taken declined, while pocket gopher numbers steadily increased from winter through fall.
Madera County foothills (Fitch, 1947). This study was conducted in the blue oak-Digger pine belt of the Upper Sonoran Zone of Madera County. The region is comprised of rolling foothills broken by numerous ravines, and includes substantial grassland. Barn owl pellets were collected over four years at four sites. Computed on a prey weight basis, the pocket gopher accounted for 71 percent of the diet of the barn owls. Pellets were also collected from day roosts of great horned owls, which were far more numerous than barn owls in this area. The diet of the great horned owls consisted largely of Jerusalem crickets, woodrats, cottontails, kangaroo rats, and pocket gophers. On a weight basis, 56 percent of the diet was cottontails. For comparison, the diet of red-tailed hawks was also presented from a related study. On a weight basis, 50 percent of the diet of the hawks consisted of ground squirrels.
Coastal Los Angeles County (Cunningham, 1960). Pellets were collected once from the base of a date palm tree. Because of the abundance of wood rats and the low percentage of pocket gophers and meadow mice, the author concluded that the barn owls foraged largely in the chaparral-covered Santa Monica Mountains about two miles north of the collection site. Two samples of great homed owl pellets were also taken; their diet consisted mostly of pocket gophers, house mice, meadow mice, and wood rats.
Placer County (Clark and Wise, 1974). Pellets were collected at eight sites along the eastern edge of the Sacramento Valley, mostly from barns just northwest of Lincoln. On a weight basis, over half of the diet of the barn owl consisted of pocket gophers, while white-footed mice accounted for only about seven percent.
Siskiyou County (Rudolph, 1978). This study examined the coexistence and diets of barn owls and great horned owls at Tule Lake National Wildlife Refuge. The owls roosted on rock cliffs with a hunting range that included natural vegetation and agricultural fields. Pellets were collected at weekly intervals from the roosting sites. The diet of the great horned owls was very similar to that of the barn owls. Barn owls were found to hunt primarily on the wing, while great horned owls hunted primarily from telephone poles.
References
Clark, D.R. and C.M. Bunck. 1991. Trends in North American small mammals found in common barn owl dietary studies. Canadian Journal of Zoology 69:3093-3102.
Clark, J.P. and W.A. Wise. 1974. Analysis of barn owl pellets from Placer County, CA. The Murrelet 55(l):S-7.
Colvin, B.A. 1986. Barn owls: Their secrets and habits. Illinois Audubon, No. 216, Spring 1986.
Cunningham, J.D. 1960. Food habits of the horned and barn owls. The Condor 62:222.
Evans, F.C. and Emlen, J.T., Jr. 1947. Ecological notes on the prey selected by a barn owl. The Condor 49:3-9.
Fitch, H.S. 194 7. Predation by owls in the Sierran foothills of California. The Condor 49:137-151.
Foster, G.L. 1927. A note on the dietary habits of the barn owl. The Condor 29:246.
Hall, E.R. 1927. The barn owl in its relation to the rodent population at Berkeley, CA. The Condor 29:274-275.
Hawbecker, A.C. 1945. Food habits of the barn owl. The Condor 47:161-166.
Jameson, E.W., Jr. and H.J. Peeters. 1988. California Mammals. University of California Press, Berkeley, CA.
Rudolph, S.G. 1978. Predation ecology of coexisting great horned and barn owls. The Wilson Bulletin 90(l):134-37.
Smith, C.E and C.L. Hopkins. 1937. Notes on the barn owls of the San Francisco Bay region. The Condor 39:189-191.
For more information write to: Chuck Ingels, UC SAREP, University of California, Davis, CA 95616.
(CI-PEST.137) Contributed by Chuck lngels
June 20th, 2006
.theava.com
by Rob Lee
Whether the Giants are winning games in big fistfuls, or can’t produce as much offense as a foul-mouthed grandmother, there’s always a good reason to go to their ballpark. I’m not talking about the starlings foraging in the outfield grass, or the hordes of Western gulls that begin gathering faithfully during the seventh-inning stretch (although the best seats for my proposed entertainment are in the upper deck, with the gulls).
I’m speaking of the barn swallow and the white-throated swift, foraging on all those beer-crazed bugs rising off the crowd. While these birds are seemingly quite similar — long, swept-back wings, the aerodynamics of great fliers — the swallow is a song bird and the swift is not; actually more closely related to hummingbirds.
Sitting high in this bird observation platform, formerly known as the Giants’ home, you’ll notice that the two birds have different flying techniques. The swallow cuts a graceful, complicated swath through the air, constantly maneuvering to pick off one insect after another, while the swift is just that; flashing under the stadium lights like a jet, using a few quick, powerful strokes of its wings and then a short glide, eating the tiny insects — “aerial plankton” — in its path.
The white-throated swift may be the fastest bird in North America, once estimated to have fled a swooping falcon at more than 200 mph. It could easily keep pace with, inspect and then pass a soaring Barry Bonds homer. Both of these birds have wings “built for speed,” but the swallow has slender, flexible wing bones suitable for its elegant flight, while the swift has shorter, more massive bones (and long primary feathers), with which it can achieve the stiff, superfast wing beats that give it surpassing speed.
Swallows typically fly lower to the ground, pursuing insects (their hard work providing a very nutritious diet), while swifts fly high, on a line, and much longer distances, hunting for clouds of anthropoids to charge through repeatedly. While the swift’s flight uses less energy, it also yields less nutrition in the types of insects caught. (Swifts typically fly more than 500 miles a day, and, as they are long-lived for small birds — larger swifts may live more than 20 years — well over a million miles in their lifetime.)
Both birds do nearly everything in flight, including drinking, bathing, courting, and, among swifts, copulating. Some swifts, after mounting high in the sky, are even thought to sleep in flight.
Flying is so central to the lives of these birds that the swallow can only walk with difficulty and the swift can’t walk at all. Swallows have tiny, weak legs and feet that only allow perching on such things as wires or thin twigs. Swifts’ legs are virtually nonexistent, but they have tiny, strongly clawed feet, all four toes facing forward, with which they can hang on vertical surfaces, such as cliffs or buildings.
Barn swallows are a really lovely bird, artistically colored in blue, rust and buff with a long swallowtail, while the swift is basic black and white.
Barn swallows raise four to five chicks in their mud-and-grass cup nest, usually affixed under the eaves of a building or beneath a bridge. (These swallows have used human structures for nesting so widely, and for so long, their natural sites are virtually forgotten.) White-throated swifts raise a similar brood in very inaccessible crevices in cliffs, and sometimes buildings. Gathering twigs on the wing from dead trees, they build a cup nest, which they cement in place, and together, with saliva.
The close proximity to people with which these swallows consistently nest makes them one of the easiest nesting birds to observe, while this swift is just the opposite, with relatively little known about its nesting behaviors.
Both birds migrate, but the white-throated swift doesn’t go very far, usually not beyond the Southwest. The barn swallow is a champion long-distance migrator, some birds going 7,000 miles each way. Both of these species are social, usually found in small to large flocks, although the individuals I saw at the ballpark were alone.
I can’t promise the birds will show up when you go to a game, but if they do, it will be a joy to watch their two styles of mastery above the crowd, the two species, in a way, mirroring the combination of relaxation and intensity that characterizes baseball.
June 20th, 2006
Peterborough, N.H.
mledger.com
A Column By Francie Von Mertens
The tide has turned. It turns slowly, and then really gets going. Mid-May brings the biggest surge of birds — a combination of species that nest locally as well as some passing through to nesting grounds farther north.
I’ve kept a birding calendar for 10 years now, and this time of year each day gets an entry. Today’s came late, in the sunset hour.
Overhead, elegant as always in flight, its rust-colored front accentuated by a sunset glow, a backyard favorite made its first appearance of the year. I checked to make sure both barn door and hayloft door were opened wide and welcoming.
Barn Swallows arrive in late April with the same general punctuality as other migrants — sometimes arriving the same day as previous years; sometimes within the week.
The Barn Swallow high overhead had Tree Swallows for company, their fronts showing white and their tales squared rather than swallow-tailed. It took a search with binoculars to finally find a companion Barn, and then, in time, a third among the majority Trees.
They were foraging high. As light faded, I wondered where they would spend the night when two swallows swept lower and lower. For the first time since last Aug. 28, our barn will host Barn Swallows for the night.
Aristotle is quoted as saying, “One swallow does not make a summer.” The day the first Barn Swallows returned to our barn was a glorious summer day, but we all know there’s more cold to come. One glorious, T-shirt day, however, and we forgive the long spells of wet and cold.
Aristotle’s swallow was the same species as our Barn Swallow. In Europe it’s called “Swallow.” As one of the most cosmopolitan species, it’s at home throughout the northern hemisphere.
My birding calendar has a new entry under April 28. In capitals. “HAWKWATCH!”
The fall hawkwatch is a big deal, marked by school field trips, birding groups, hawks-in-flight workshops. The dramatic fall flights draw crowds to certain hawkwatch hotspots. Come spring, hawk migration is more dispersed, and as mortality is high far more hawks depart in fall than return in spring. There’s no such thing as a local spring hawkwatch.
That being said, while working at the local community garden last Sunday with two friends who are ace birders, we were distracted by an Osprey, a kestrel, a Sharp-shinned Hawk, all heading north as blue sky returned.
Two days before, Don and Lillian watched over 80 hawks from their backyard during a two-hour period. Most were Broad-winged Hawks; 16 were Ospreys. That day offered a clear patch of weather surrounded by rain. Don said the hawks read weather well, and often move ahead of a cold, wet front.
Garden chores rushed to completion, we formed a mini-hawkwatch in their backyard as hawks rode wind currents along what they call “Bobcat Hill” and then Crotched Mountain across the river. Don and Lillian’s backyard is a sloping field down to a Contoocook River made wide and slow by the Bennington dam.
Migrating birds favor flyways along north-south rivers, ridgelines and coastlines. Besides navigational assistance, river corridors provide unequaled food resources and ridgelines provide updrafts to ride. The Stokeses’ backyard benefits from both river and ridgeline, but under certain conditions every backyard in the region can have hawks overhead.
Last Sunday’s “HAWKWATCH!” was the first-ever spring hawkwatch entry in my calendar. Next year the entry will remind me it’s time for the second annual spring hawkwatch.
We also watched a multitude of swallows bickering over nestboxes and foraging above the Contoocook for emerging insects. When we found a few Barn Swallows in the group, Lillian pointed to their barn where a broad hayloft door was open. Fixed open.
Besides an open door policy, they nailed small platforms to the loft rafters. As still further inducement and an experiment, they placed two decoy Barn Swallow nests (manmade) in prominent view.
Declining in New Hampshire, Barn Swallows are “a species of conservation concern” in the state. So open your garage and shed doors wide, nail platforms to the rafters, and keep your fingers crossed.
The poet Robert Lowell wrote, “One swallow makes a summer.” He’s right, too. The sight of the first Barn Swallow overhead summons summer thoughts of Barn Swallows swooping low to country fields that shimmer in the summer heat.
Note: Don’t miss the talk on climate change next Wednesday by George Hurtt from UNH. He’ll give the topic a regional and national focus, and make clear what is known with scientific certainty. As added interest to birders, he’ll explain the role of the northern forest in moderating climate change. The topic deserves a full house. Time and place: Wednesday, May 7, 7 p.m. at ConVal High School in Peterborough.
Backyard Birder appears every other week in the Monadnock Ledger.
June 20th, 2006
americanartifacts.com
On many properties, finding a good site to place artificial nest cups is difficult. Barn swallows demand adequate protection of the nest from rain. Modern homes often don’t have adequate overhang of the eaves to provide this protection. Also, placing nest cups under the eaves of a two story house is more than many home owners want to attempt.
The use of shelters specifically designed for barn swallow nesting has become a feasible idea when fitted with artificial nest cups. The presence of nest cups greatly increases the chances of such structures being used by swallows.
A single nest shelter
The most basic structure is a wall mounted single nest shelter. This shelter allows the nest to be placed anywhere on a wall rather than just up under the eaves or on a porch. The roof should be adequate to prevent blowing rain from reaching the nest. I will be trying several single nest shelters this spring, testing both horizontal and vertical spacing on the wall of our barn. The swallows may not be interested in nesting at multiple levels, but it’s worth a try since an entire colony could then be housed on a single wall.
Two post free-standing shelter
A simple free-standing multi-nest shelter is a gable roof mounted on 2 posts, much as a wishing well roof, only longer. The shelter should have a ceiling and a 1 ft apron on all four sides. The nests can be mounted on the inside of this apron or back to back on a board running down the center. On the 4 ft wide version, nests can be mounted on both sides and on the center board. The nests should be at least 8 ft. above the ground. An even higher structure with the nests around 12 ft. above the ground may be more appealing to the swallows, especially if humans are a problem in your area (children with long sticks). However, this tall a shelter is more difficult to build and the nests will be less accessible for monitoring and emptying. Where human traffic isn’t heavy, an 8 ft. shelter may be preferred.
2 pole shelter diagram - end view - - - 2 pole shelter diagram - top view - - - 2 pole shelter for maximum privacy
4 post free-standing shelter
Similar shelters wider than 4 ft require 4 corner posts. Nests may be placed on several boards running along and perpendicular to the ceiling. Nests can be placed on both sides of the boards, or if closely spaced, on one side only. An ideal pattern of nest placement has not yet been determined. Careful observation of new shelters fitted with nest cups, noting which cups are used first and which are not used is a useful research project for anyone building such a shelter. If the joists run across the width of the shelter rather than end to end, a single nest placed on each joist would not be in the line of sight of any other nest. This arrangement should be tried, but, several nests in view of another nest should also be tried. Swallows often seem to spread out within a colony room, seeking the maximum space between nests. However, I have frequently observed two pairs of swallows choosing to nest fairly close together, especially when they are nesting at a new site. Like most animals, swallows spend a great deal of time and effort trying to avoid being eaten. A benefit of colonial nesting is that each bird can spend less time watching for predators, relying on other members of the colony to share the watch. Having another pair nesting close by and in line of site may be reassuring to the swallows
4 pole shelter diagram - end view
I set the posts today for an 8×12 shelter which will have 12 nest cups. Hopefully it will be finished before the swallows return.
Lean-to shelter on an existing building
Where a shed or other outbuilding is present, another option is to attach a lean-to on the side of the building, supported at the other end by 2 or more posts. Care must be taken that the roof and supports are strong enough to hold a snow load, including what might slide down the roof of the shed. Unless the roof is in afternoon shade and has a shallow slope, there should be a ceiling above the nests to protect them from overheating and to allow proper nest placement with 2″ clearance above the rim. The resulting attic should be vented at each end. Or, better still, in hot climates, the attic should be insulated. The eaves of many small sheds are too low to allow an 8 ft. lean-to addition. Swallows have accepted nest heights of 6 ft in sheds or other sites where they are seldom disturbed. But, if possible, 8 ft. is a safer minimum height. A somewhat lower entrance is no problem and may actually be preferred. An entrance lower than the nests gives greater protection from the weather as well as from prying eyes of passing predators. The 12 inch apron around the top of the shelters illustrated above allows nests to be placed at the edges of the shelter with total protection from the weather. This maximizes the number of nests that will fit in a given size shelter, however they are arranged.
lean-to shelter diagram - end view
Shelter construction
The above information does not cover the methods of construction of the free standing shelter. The method you choose is immaterial to the swallows and should fit your needs. The shelter must be sturdy enough to withstand wind and snow load and the nest area must be protected from the weather. Very economical shelters can be made from materials at hand, such as left over shingles and 2×4’s from a construction job. On the other hand, an elaborate shelter with decorative trim or a design to match your house may be an interesting addition to your yard. A store bought gazebo would make an ideal, if expensive, swallow shelter. The swallows won’t care which you choose. Their interest lies in weather protection, height of nests, placement of nest in relation to other nests, and protection from predators.
Swallow nest selection in your shelter
As swallows colonize your shelter, records should be kept of which nest cups are used and what relation they have to other nests. This will help establish a minimum distance acceptable for the following conditions.
A. Distance between nests mounted on a common joist.
B. Distance between facing nests on adjacent joists.
C. Distance between nests on opposite sides of a joist. These are not in line of site of each other.
diagram of measurements A, B, and C
Dual use swallow shelters
Since there is no guarantee that swallows will colonize a shelter that you build, the idea of a secondary purpose for this structure is worth considering.
Simultaneous dual use A storage shed, car port, or other structure may be fitted with swallow nest cups if a window or door can always be left open and the droppings from the swallow nests can be tolerated. The droppings will be confined to the area directly below each nest and can easily be collected on a newspaper or plastic flower pot.
Seasonal dual use The swallow colony will use a shelter only during nesting. In Maryland, this is from mid April to early August. This allows the shelter to be used for winter storage of such items as lawn furniture, or maybe a riding mower, if you use one of those things.
Secondary use Until the swallows take up residence in your shelter, a secondary use will take the pain out of having an unused shelter. This use should not interfere with the appeal of the shelter to swallows, or they may never come. Gazebos are an ideal secondary use structure.
Richard Van Vleck
richard@americanartifacts.com
June 20th, 2006
americanartifacts.com
PURPOSE
The use of artificial nests to attract barn swallows to a new site depends on their acceptance of these nests. To test the acceptance of artificial nests by barn swallows, the nests were offered to our colony of swallows, who also had access to old nests and plenty of unused space to build new nests.
METHODS
What had begun this winter as a nesting shelf project to encourage multiple nestings of barn swallows has evolved into something quite different. My goal was to make a small nesting shelf that fit the swallows’ requirements while blending in with the architecture of a house. The idea was that more people would be willing to place multiple swallow shelves on their house if they appeared to be a part of the house. At the same time, I took careful measurements of 40 swallow nests and began making a variety of artificial nests. The nests were made of various materials molded over a wire form secured to a backboard which could easily be screwed to a wall. Even if it turned out that these nests would not be used, they might encourage swallows to build their own nest nearby, sort of acting as a decoy.
A portion of the swallow colony room was modified for the shelf and nest test. A plastic tarp was stapled under the joists, covering both the old nests and the joists upon which the nests were built, effectively making a new lower ceiling. The locations of the old nests were noted so I could avoid placing a shelf or artificial nest directly under an old nest to rule out nest site fidelity as an important factor in the swallows’ selecting a new site. Simulated walls were then constructed of sections of cheap paneling secured to 2×4’s to provide a slick surface similar to modern plastic or painted siding. The partitions extended down 24″ from the ceiling. The other side of the colony room was left unchanged, making available both previously built natural nests and plenty of unused space on the hand hewn beams for building new nests.
When our swallows began to return (a week late this year), several of the turned shelves were mounted on the panels. The swallows immediately began dabbing mud on each shelf. No other nest building activity was noted. Happy that they were apparently claiming the shelves, I mounted several artificial nests between the shelves, but no closer than 4 feet from them or each other. The swallows instantly began adding mud to the nests and ignored the shelves, except to use as convenient perches. I decided to place the artificial nests lower than the 1 1/2″ rim to ceiling distance required, in case the swallows needed to add some mud as part of the nest building ritual. Most of the nests in use have the rims built up. I haven’t measured the exact height of their mud additions yet. I plan to move some of the unused nests up to the 1 1/2″ clearance for the second nesting to see what happens.
RESULTS
On May 19, 2001, 7 artificial nests had eggs and 2 previously built natural nests had eggs. No new nests had been built, either on the beams or on the new shelves. By May 31, 2001, nine artificial nests had eggs or young and 3 natural nests were used. and still there was no new nest construction. Two of the artificial nests in use were mounted in the undisturbed area on the side of the beams. The other seven were mounted under the tarp on the simulated walls. There are still plenty of both unused artificial and old natural nests available. Several more pair are likely to nest soon and, later, the second brood is often reared in a different nest, so much more will be happening this summer.
The overwhelming acceptance and even preference for the artificial nests among the swallows in our barn colony suggests that these nests may play an important role in attracting swallows to new sites. Just as important, those people finding a swallow nest blocking their front door or or otherwise causing a problem may find that placing an artificial nest off to one side of the door or even on a different wall may be the surest way to coax the swallows to move.
Update 6/16/2001 Eleven artificial nests have now been used. Six have nestlings, 4 have eggs and the young have fledged from one. There are still only three natural nests that have been used (two with nestlings and one where the young have fledged. Still no new nests have been built this year.
Update 6/30/2001 With many second broods begun, 3 new nests are finally being built - one on a provided shelf and two on the side of beams. So far 12 artificial nests and 4 old natural nests have been used. Two of the artificial nests have been reused for 2nd broods. The three new natural nests are almost completed and should have eggs very soon. Usually, a nest is not used for two consecutive broods, which may explain why the 3 new nests are finally being built. However, there are still unused artificial and natural nests available.
It occurred to me that emptying the artificial nests after the young have fledged may lead to more frequent immediate reuse. I’ve never cleaned out a natural nest because they are too fragile and the nesting material is embedded in the mud. However, the artificial nests can be easily emptied of all nesting material, including the mud rim that was added to some of them. I cleaned all the nests today, but many second broods have already begun, so it may be too late to detect a difference in reuse of emptied nests. The one thing that was clear is that the artificial nests are preferred by barn swallows.
Update April 4, 2004 After several years of using artificial nests, it appears that the economy wood nests are as attractive to swallows as the heavier and more expensive plaster nests. Also, I now routinely empty the nest cups after each nesting, in order to reduce the mite population, which tends to build up with each nesting. It’s hard to tell if this has improved the outcome of third nestings, since other factors, especially weather, play as important a role in mid-summer nesting success. However, reuse of the same nest for consecutive broods has increased since initiating this practice.
Richard Van Vleck
richard@americanartifacts.com
June 20th, 2006
nhptv.org
CLASSIFICATION
Phylum: Chordata
 Class: Aves
 Order: Passeriformes
 Family: Hirundinidae
 Genus: Hirundo
Characteristics
The barn swallow is about six inches long and has a dark slate blue head and wings. It has a dark rusty orange throat and forehead and a paler orange chest and underside. It has a deeply forked tail. Males and females are similar, but the female’s tail is a little less forked and her underparts are a little paler.
RANGE
In North America, the barn swallow breeds from Alaska east to Newfoundland, Canada and south to California and east to northern Florida. The barn swallow is a Neotropical migrant. It leaves its breeding range in the fall and travels south to winter in Mexico, Central America and South America. It travels by day, eating as it flies. It can travel as many as 600 miles a day. Barn swallows migrate in large groups. The barn swallow also breeds in northern Europe, northeastern Asia, the Middle East and Northern Africa. European and Asian barn swallows winter in southern Asia and Indonesia and Micronesia.
HABITAT
The barn swallow can be found in farmlands, suburbs, marshes and lakeshores.
DIET
The barn swallow is an insectivore, it eats only insects. Grasshoppers, beetles, moths and other flying insects make up a large part of its diet. The barn swallow zig-zigs through the air in pursuit of its prey. It even gets its water while flying! It will skim over the surface of a body of water and scoop up water in its bill.
LIFE CYCLE
Barn swallows form breeding pairs in the spring when they return to their breeding grounds. The male tries to attract a female by spreading his wings and singing. Barn swallows often mate in the air. Both parents build the nest. Nests are made of mud and lined with grass and feathers. The barn swallow pair will gather mud and roll it into a pellet and then carry it back to the nesting site in their bills. The cup-shaped nest is built in the rafters or eaves of buildings, on bridges, in mine shafts or on other manmade structures. Occasionally, the barn swallow will build a nest under a rock ledge or cliff face, but that is rare. Like their name suggests, barns are one of the favorite location for barn swallows to build their nests and a single barn may be used by five to eight pairs of barn swallows.
The female lays four to six eggs. Both parents help incubate the eggs and care for the young. The eggs take around two weeks to hatch and the chicks will fledge when they are about three weeks old. The parents will continue to feed them for up to a week after they fledge. The female may have two broods a year. The same pair may mate for several years.
BEHAVIOR
The barn swallow uses a variety of vocalizations to communicate. It has an alarm call to warn of predators and a mating call used to attract a mate.
June 20th, 2006