Richard and Diane Van Vleck Personal Pages
The Home Habitat

barn swallow at artificial nest cup

The need for colonial sites

In traditional swallow colonies, there is a great deal of social interaction including non-parent "helpers" feeding the young of others and egg tossing by bachelor males. The complex interactions of the swallows nesting in a colony are not only fascinating to observe, but, are, likely, advantageous to the species. The trend toward single pair nestings in the "new suburbia" can, perhaps, be reversed by simply offering multiple nest sites on a porch, gazebo, carport, or under a deck.

In the past two years since posting these personal pages, several hundred people have emailed asking about either how to get rid of barn swallows nesting on the light fixture over their front door or how to attract swallows to their property. The majority of people emailing us about swallows have a single pair nesting on their porch or under their eaves or deck. They often state that they had several pair in their yard in the spring, but only one pair stayed to nest. The frequency of single pair nestings was a surprise to me, since my experience has been with large or smaller colonies, both on our property and elsewhere. Here in the East, old barns are disappearing at an alarming rate and many long term colonies of swallows have been forced to disperse. Coming back from South America in the spring to find the old barn gone and a massive housing development going up must be as disconcerting for the swallows as it is for some of us. This probably accounts for some of the individual pairs nesting over porch lights.

What we can learn from traditional colonies

Since barn swallows are semi-colonial nesters, it would seem that providing several nesting shelves in the proper location would be much more appealing to those pairs searching for a new nest site. After studying the 40 plus nests currently in our resident colony, several factors have become apparent. The entire barn structure is rough cut wood, so the swallows are free to build their nest anywhere, rather than using shelves. In fact, only two of the 40 nests have been built on any sort of substantial projection or shelf. They seem to prefer building on a vertical wall of rough wood, often over a small projection such as a protruding knot or nail.

Every nest in the colony has its rim approximately 1 1/2" from the ceiling. The swallows seem not to mind unusually low or high ceilings, they just prefer to build right up near the ceiling. This may have to do with predator avoidance or protection from driving rain. Mud nests plastered on a wall cannot get wet or they will soon fail. Also, none of the nests in our barn are in a corner, suggesting that they prefer a 180 degree view from their nest. Nesting shelves should probably have open sides, unlike some of the "robin shelves" being offered for barn swallows. This is, of course, just conjecture. But the 1 1/2" ceiling clearance does seem to be important. The two nests in our colony where a ledge was used are built up 2 inches higher than normal to reach the 1 1/2" ceiling clearance. These nests were built on a board that someone had nailed to the underside of two adjacent floor joists many years ago. The two nests were built on the projecting ends of the board. Interestingly, no nest was ever built on the length of the board running between the two joists. Swallows do not like continuous ledges or shelves, probably because rats can easily reach the nest by crawling along such horizontal surfaces. With a long history of nesting in barns where grain is stored, they must certainly have had to adapt to sharing their habitat with rodents. None of the shelves I provided in the colony room have ever been used because they were all boards nailed on the underside of beams that average 8" to 12" thick, thus too far from the ceiling for the swallows' liking. The average base of the swallow nests is 5 1/2" below the ceiling. Nesting shelves provided in my workshop where all the wood is planed and painted were readily accepted when they were placed 5" to 6" below the ceiling, but not when inadvertantly placed substantially lower.

The closest two nests in the barn colony are 20 inches apart, while many nests are located within 24" of another nest. These adjacent nests are usually not used simultaneously. One is often used for the first nesting and the other for the second in a given season. Simultaneous nests are usually greater than 4' apart on the same beam. This does not apply to nests on opposite sides of the beam, where they may be back-to-back.

Oddly, it has been those nests built outside the colony room that have deviated from the norm. A small room at the rear of the colony room and open to the larger room had never been used by swallows until one year two pair built nests there. The nests were simultaneously built very close together, on a continuous ledge, and well below the ceiling. Both pair successfully raised a brood, but the nests have rarely been used since then and never simultaneously. Another nest has been built in this room on the side of a beam and in the preferred manner. Two pair of swallows moved into my workshop one year and also built nests very close together and too far down from the ceiling over electrical outlets. I removed these nests and provided several nesting shelves 15 feet away which were immediately used. Thus, all of the odd nest sites were selected by pairs who left the colony room. While we used to call the workshop swallows "loners", I now think that these and subsequent pairs that nested elsewhere than in the colony room were young first time nesters. They may not have been allowed to nest in the colony room. Even though there seems to be plenty of room left to build new nests, the activity at nest selection time is frantic. There are few real battles, but a great deal of high speed aerobatics and shrill chatter. The severe competition for nest sites may sometimes be too much for young timid swallows. The fact that two pair have twice left the colony together and nested unusually close together in the new location may be simply coincidence, but bears further consideration.

Of course, all of the above guidelines are frequently broken by swallows nesting on porches and other locations where their mud nest will not adhere to planed and painted wood or aluminum or plastic siding. Here they must resort to building on a ledge, door frame, light fixture, or other projection, even if it it 2 feet from the ceiling or on a continuous ledge. While such locations usually offer adequate protection and a successful nesting results, the trick is getting the swallows to choose such a site. This may be why many people have reported that they have had 4 or 6 swallows hanging around their porch in the spring, but only one pair stays and nests while the others move on. Perhaps only one pair was willing to settle for a less than ideal nestsite - usually over a porch light or door frame.

Artificial nests for Barn Swallows

Updated 6/2/2001 Finally enough data is in on the usage of artificial nests in our colony to begin making and offering the nests for sale. Due to the swallows' great preference for these nests over shelves and apparently even over natural nests, I have discontinued making the various nesting shelves. As of 5/27/01, the barn swallows in our colony have begun nesting in 9 artificial nests, and 3 natural nests. They have built no new nests, including on the shelves provided. For details, see the link below.

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 4/5/2002 Two unusual events happened in the barn colony during the 2001 season. On August 10, all the young in the four remaining nests were found dead. The temperature had been around 100 F. for several days in what was otherwise a mild but very dry summer. A very heavy mite population was found in all four nests as well as fairly heavy blowfly infestation. I don't think nest temperature was an important factor, since the colony room in the lower level in our bank barn is always the coolest place on our property. It is much cooler than, for example, our upstairs bedroom. It's possible that the heat and long term drought made it harder for the adults to find enough food. We were away for several days when this happened, but the adults were still present when the nest failures were discovered. This was the tail end of the nesting season, with only 4 nests still containing young. The earlier broods were all healthy and fledged with no problem except for the second unusual event.

On June 6, the female fledgling kestrel entered the swallow room and dined on young in 4 nests, making several visits on one afternoon. She never returned on later days and left the area a week later, long before her 4 male siblings. The mysterious disappearance of some or all of the young in four nests was quickly resolved by fast forwarding the day's videotape of one of the nests.

A kestrel attack - still pic of the swallow nest video

This is the first time in 16 years of close association that a kestrel has entered the swallow room or bothered them in any way. The only thing different this year is that the kestrels nested a month earlier than in all previous years. The fledglings usually live on grasshoppers for their first week or so, but this year, large insect prey was harder to find at the time of fledging. While this seems to be a unique event, I decided to move the kestrel box from the barn wall to a much more distant location. A large kestrel tower was erected in mid March in front of the house and the pair have already moved in.

Update 9/29/2004 While these swallow pages are offered to those who want to attract barn swallows to their yards, the preponderance of email over the past 4 years has been from people who want to get rid of swallows. During the nesting season, this site receives around 20 emails per day concerning barn swallows. Mail from the first part of the 2004 season was categorized as to intent. Where intent wasn't clear, the message was excluded from this data.

Over the past four years, a surprising number of people have written that they were afraid of swallows that dive-bombed them when they approached the nest. While they didn't mention how they thought a songbird weighing less than one ounce might harm them, their fear was genuine. I don't know the answer to that problem, other than to suggest they spend more time outdoors and become familiar with the other creatures who share their yard.

While the overwhelming majority of email has been from people wanting to drive off barn swallows because of the droppings under their nests, it may be that this isn't indicative of the attitude of most Americans. Many people, myself included, seldom take time to do a web search unless they are looking for an answer to a problem. It may be that people who like their barn swallows simply have no need to search the web for that term and never come across this site.

The above emails arrived early in the 2004 nesting season. Later in the season, we always receive many emails asking how to care for nestlings that have fallen from the nest (a very common occurrence). Including these messages would greatly alter the like versus hate ratio, but a computer crash caused the loss of all the mid-season messages.

March 20, 2008 update This week I am emptying the swallow room of all the antique machinery and parts for the first time in 20 years. This will allow easy nest checking with a flash light and a mirror on a stick for the first time in several years. This may also be a good year to resume videotaping the swallows. My current interests include the percent of male incubation vs temperature and the degree of nest parasite infestation vs nesting productivity. Both of these topics have already been explored by others, so I don't expect anythng new. But, following the year of the flicker and the year of the polygamous barn owls, this may once again be a year of the barn swallows.

Richard Van Vleck
richard@americanartifacts.com


Order barn swallow nest cups
A new barn swallow shelter
2012 barn swallow nesting
2012 barn swallow prey cam
Using artificial nest cups
2015-2016 barn swallow nesting
Attracting barn swallows
The Barn Swallow
barn swallow basics
Transplanting a barn swallow nest
2001 testing nest cups
barn swallow shelters

2010 - 2014 Northern flicker nestings
2014 house wren gourd use
2014 - A dramatic loss of many types of insects
barn swallow artificial nest cups
2014 barn owl nesting - prey study
A new barn swallow shelter for 2013
2010 barn owl nesting
2010 Update
Entire site index (outdated)
Starling traps
Using blinds in the home habitat
Providing perches for birds
Providing snags for wildlife
The ugly young maple
2001 - 2013 nest cams
Use of tomato cages as hunting perches by insectivorous song birds
Vultures, beetles and the resurrection of life

Species of interest in our yard - photos and articles
barn owl American kestrel purple martin barn swallow Eastern bluebird
tufted titmouse Eastern phoebe yellow shafted flicker tree swallow chimney swift
house wren big brown bat Carolina wren brown thrasher catbird
cedar waxwing Northern mockingbird
Yellow warbler Acadian flycatcher

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