Blane Klemek column for June 21: Swallows are marvelous birds
Although my dad complained once in a while about the bird droppings on the floor of our dairy barn, he never once, as far as I know, knocked down or destroyed any of their nests. I'm pretty sure he enjoyed their antics and company as much as I did. In and out of the barn they'd fly -- building their nests or adding a new layer of fresh mud to an old nest, and, later, feeding their fast-growing nestlings.
At summer's end, typically after the second broods had all fledged, the power lines strung from the yard-light pole to the barn would be lined with rows and rows of chattering barn swallows. I loved those birds, and I still do, for barn swallows and their relatives are as delightful, acrobatic, and social as they come. Indeed, many species readily accept artificial nest boxes and human-made structures to nest inside, within, on or around.
As soon as springtime warms enough to where insects are fairly abundant, several species of swallows begin showing up throughout Minnesota. In all, six of the nine North American species of swallows migrate to Minnesota to breed and nest. All share similar physical characteristics with one another, but each is unique in its own right.
Topping the popularity list of Minnesota swallows is the largest of the swallow clan, in addition to the only species of swallow not to have "swallow" as part of its name. The purple martin is that condo-loving, social butterfly of the swallow world. Here is a swallow that has come to rely almost exclusively, interestingly enough, on human-made bird houses for nesting.
Like several other swallow relatives, purple martins are cavity nesters; specifically, they evolved to nest inside holes in trees. But perhaps due in part to loss of their preferred nesting habitat (larger trees with suitable tree cavities), these colonial nesting birds somehow adapted to nesting in birdhouses.
Evidently, purple martins east of the Rocky Mountains rely almost entirely on "human-supplied housing," whereas those birds nesting west of the Rockies typically nest in their ancestral ways -- that is, inside tree cavities.
Two other species of swallows occurring in Minnesota each year are referred to as "brown" swallows: the northern rough-winged swallow and the bank swallow. Honestly, I'm not certain if I've ever observed the rough-winged swallow, but I'm quite familiar with bank swallows.
Having spent countless hours canoeing the Crow Wing River, which meanders through Hubbard and Wadena counties, I have regularly seen bank swallows along the sandy, high banks commonly encountered alongside the river.
Both species nest in holes they excavate themselves in sandbanks. Obviously, the sand of choice has to be of the right consistency, otherwise their burrows would collapse. Bank swallows, the more sociable of the two "sandbank swallows", are colonial nesters, whereas northern rough-winged swallows nest singly.
Having observed the former species along the banks of the Crow Wing many times, it's a pleasant experience to watch bank swallows capture insects above the surface of the flowing river. It's mesmerizing to see tens of dozens swoop and dart in their haste for food, they just as quickly return to their sandbank cavities to feed hungry nestlings.
Another common swallow that nests in Minnesota each season, frequently near water and often underneath bridges, inside large culverts, or beneath the eaves of buildings, is the attractive cliff swallow.
Here's a species of swallow that builds perhaps the most unique of the nest-building swallows.
Shaped like gourds, cliff swallow nests are constructed entirely out of mud pellets composed of sand, silt and clay. From 1,000 to 1,400 mud pellets (which also represents that many mouthfuls of mud and trips to the nest!) and a period of one to two weeks is required to complete the construction of each individual nest.
The last two swallows occurring in Minnesota are my favorite swallows. I am forever grateful that, because of their abundance and eagerness to utilize birdhouses, the ubiquitous and cheery tree swallows have helped fill the numerous vacancies that most of my "bluebird" houses generally provide.
Tree swallows are stocky, broad-winged swallows with very white breasts, giving them an almost penguin-like appearance when perched with folded wings. Widespread among all swallows, tree swallows, like purple martins, choose tree cavities and bird houses for nesting and raising offspring.
As swallows go, tree swallows are aggressive, especially the males when defending their nesting territory.
The species' assertiveness is undoubtedly a primary reason why tree swallows are known to out-compete eastern bluebirds for suitable tree cavities and birhouses.
Therefore, in recognition of this trait, it is advisable to erect pairs of bluebird houses at a distance of no more than 10-20 feet apart, or back to back on the same post. Thus, since tree swallows don't allow other tree swallows to nest within 20 feet, the other nearby birdhouse is free for a nesting pair of bluebirds to use.
And lastly, as already mentioned, is the sweet and beautiful barn swallow that I came to know so well as a young boy on the farm. This orange-breasted swallow with the deeply forked tail, is an elegant-looking, easy-flying swallow that to me exemplifies grace on wing.
Constructing its half-cup nest of mud and organic materials under the eaves of buildings or onto rafters or floor joists inside buildings, the tolerant barn swallow seems unaffected by human activity.
Swallows, all of them, birds designed for capturing flying insects while they themselves careen through the air with no apparent effort, are birds to marvel at as we get out and enjoy the great outdoors.
Blane Klemek is the Bemidji area assistant wildlife manager, DNR Division of Fish & Wildlife. He can be reached at firstname.lastname@example.org