Lifestyle of swallows

I often imagine that it would be great to have wings, and to be able to earn my living working as the swallows do. I’d even be willing to live on a diet of insects if I could spend my workday sailing back and forth through the sky, maneuvering effortlessly to capture those bugs – my paychecks – on the wing.

Swallows even seem to have fun on their trips to the water cooler. Never bothering to stop flying, they swoop down to the water, drop their lower beaks a bit, and skim a mouth full off the surface.

Bathing before, or during, a day’s work only requires the swallow to make a similar low pass, dropping just a bit, and either splashing their undersides without losing a wing beat, or actually dunking for a moment before flying off, refreshingly soaked.

Then, at break time, they just find a telephone wire somewhere to sit and gab with their co-workers. I have often heard these loafing swallows gossiping about those still out working, squabbling about the size of their space on the wire, and verbally competing over the size of the flying beetle they crunched out of the sky that morning – or, with the males, the size of the one that got away.

There are other advantages to their lifestyle as well. Can you imagine having the kids hatched, raised, grown, and out on their own in just five weeks?

It’s true that a week is a much larger proportion of a swallow’s life than it is ours. Assume that a person lives to 75 and a swallow to five years – the oldest recorded was about 13, but that’s rare. That would mean that a week to us is about the same as three and a half months to a swallow. Stay with me now.

For the swallows there are two “human weeks” of incubation, which is seven “swallow months.” Then there are three human-weeks – 10 swallow-months – of tending young in the nest, with the constant demands and endless chatter of the young. I’ve listened outside swallow nests, and that part of their life seems a lot like mine. I have two teens and their demands and senseless chatter goes on forever!

All day is spent supplying those demands, and it’s never enough. And I’m sure that it’s the same for the swallows. But, again, swallows are done after five human weeks, the equivalent of one and a half swallow years. And these days, our kids never do actually leave the nest, it seems. Or if they do, they return as soon as they see how tough life is out of the nest, catching their own bugs.

So, swallows spend their five human weeks out of every human-year – 17 swallow months out of every five swallow years – raising young. A five-year-old bird may have had five broods, which would have required about seven and a half swallow years raising young. That still leaves more than 67 swallow years without kids!

Plus, they take a long vacation to Mexico or to Central or South America each winter. They are gone about 30 human weeks out of the year, or the equivalent of almost nine swallow years. I’d have a whole nest full of teenagers for a year and a half if I could then have nine years in the tropics to recuperate!

And what a trip migration must be – if you survive it. That’s one of the really tough things about being a swallow. When you are only five inches long and you have thousands of miles to go under your own power, life can be hazardous. Still, what a trip if you make it, and what a life between trips.

In North Idaho we have six variations on this basic lifestyle theme, and swallows are everywhere. As I look out my window now I can see half a dozen or so violet-green swallows swooping through my neighborhood. There’s hardly a place that you won’t find them in Kootenai County.

Near any water you may confuse violet-greens with tree swallows. Tree swallows are a slightly larger, yet more simply colored, variation on the basic swallow model as represented in the violet-greens.

As a quick aside, have you wondered how the swallow got its name? It has nothing to do with swallowing. “Swallow” is what we have left in English after various translations down through the years of an old European name meaning “forked stick,” and referring to the forked tail of swallows. Oddly, only a very few species have a truly forked tail. There is only one in North America.

Our fork-tailed swallow is the barn swallow which, as does our cliff swallow, builds a unique mud nest, usually attached to some man-made structure. Barn swallows are known for attaching these nests to barns, and cliff swallows often attach to, well, cliffs. Cliff swallows also like bridges and could, for the sake of consistency, be named “bridge swallows.”

Our other pair of swallows includes the northern rough-winged swallow and the bank swallow. According to the field guides, both of these species are brown swallows that are, along with juvenile tree swallows, “particularly difficult to separate.”

One of the first things that you will notice anytime you go out to observe swallows is that they fly very fast and very erratically. That translates for the birder as difficult to keep in the binoculars and impossible to focus on.

So, in North Idaho, barn and cliff swallows are pretty easy to identify. And, while violet-green and tree swallows can be challenging, they are separable even on the wing once you get their differences in white facial and rump patterns down. The northern rough-winged and bank swallows remain, however, as major frustrations in bird identification.

To look at the pictures in the field guides, the two species appear plenty distinctive. The dark breastband just below the bank swallows crisp, white throat is strikingly different from the drab face, throat and chest of the rough-winged. Also, the bank’s tail is obviously notched while the rough-winged’s is not. But, can you really see all that in a hurtling, gyrating little-brown-body?

If you read the descriptions, you’ll see that the rough-winged is relatively large (51/2 inches), and the bank is the smallest of the swallows (51/4 inches); that the bank is relatively small-headed, and the rough-winged is stocky; the rough-winged has relatively smooth, flowing flight, while the bank flies in a quick, flickering way. The key word here is “relative.” Can you really get the two to sit and then fly side-by-side so that you can make your comparisons?

Another aside – I just can’t get enough about how birds are named. From whence came “rough-winged?” It’s because there are only two species of swallows in which the outermost wing feathers of adult males have odd little hooks or serrations. No one has figured out why.

The other species? The “southern” rough-winged swallow, of course. How can they give such horrible, plain names to such incredible little birds? And besides, only the males, as adults, have rough wings.

So, how do you tell the two apart? Actually, the best way to have a clue as to species is by observing behavior. First, bank swallows are highly gregarious and rough-winged swallows are solitary. Thus if you see a large flock of brown swallows foraging low over the water, they are probably banks. If you see one or two brown swallows foraging low over the water, it, or they, is/are probably rough-winged.

The same goes for sitting on a wire. Lots of brown swallows equals banks. One or two brown swallows equals rough-winged. However, in late summer when the juvenile tree swallows are out, or just prior to migration when species tend to mix in large flocks, you are on your own.

The most interesting aspect of these two swallows, to me at least, is how and where they build their nests. Except for colonial versus solitary, they are quite similar. It’s hard to believe, but both species dig long burrows at the end of which they build a nest chamber. Between the two, bank swallows tend to be the more industrious but rough-winged swallows are more ingenious.

Bank swallows are industrious in that they dig new burrows each year, while rough-winged swallows will often simply modify used burrows. These modified homes may be from previous years, from other swallows, from kingfishers or even from ground squirrels.

Rough-winged swallows are ingenious in their use of these old burrows, as well as in their ability to adapt to artificial burrows such as drain pipes or crevices in old buildings. Also, their solitary existence has less tendency to attract predators or spread disease than does the colonial habits of bank swallows.

For either species, however, what an undertaking, so to speak, the digging of these burrows must be. The typical burrow will be several inches in diameter, with a flat floor and an arched ceiling. They average several feet in length, but may be more than five or six feet long in both species.

And how do they dig these tunnels? The soft dirt or sand is excavated one mouth full at a time, then kicked backward out the entrance. In this tedious way, a pair may burrow three or four inches a day.

OK, one more analogy. Let’s say that a typical human step is about two feet long, and a swallow step is about a quarter of an inch long – swallows have very short legs. Roughly speaking, then, a single human foot in length would be the equivalent of 100 swallow feet in length.

A pair of swallows tunneling four inches in a day would be the same as my wife and I digging about 33 feet in a day. And we would have to do that using only our mouths and our feet. We wouldn’t be able to use our hands because, as a swallow, we wouldn’t have any.

Just think of it, a swallow’s five-foot tunnel would be 500 feet long for us. Even a typical three-foot tunnel would be a hundred yards long.

So, a swallow pair digging a three-foot tunnel at four inches per day would require nine human days, or 135 swallow days, each year. That’s four and a half months in swallow time. Can you imagine the squabbling by the end of that project?

It’s no wonder that swallows don’t mate for life. At the end of that honeymoon, it’s a wonder that they mate at all.

I still think that it would be great to work as the swallows do, to parent as the swallows do and to migrate as the swallows do. I could easily see adapting to a bug-only diet. I’d even consent to being called by meaningless names such as “rough-winged” and “swallow.”

Digging burrows with only my mouth and feet, however, is where I’d draw the line. A nest box or tree cavity would be great. A mud nest on someone’s building or under a well-traveled bridge wouldn’t even be too bad. But don’t ask me to carry the groceries down a dark tunnel, 300 swallow feet long, 100 times a day, to ungrateful teenagers. That I can’t imagine.