Swallows are perpetual motion machines, the original can’t stop/won’t stop birds. Occasionally they will rest briefly on a power line or a tree branch, but mostly, from breakfast until bedtime, it’s go go go. Paired with all that aerial vrooming is the fact that they hardly ever fly in a straight line, or anything remotely resembling a straight line. They are always climbing, dropping, banking, stalling or grinding out a long, bobsled-style curve. The concept of a direct route from A to B does not exist for them. They may be the most physically discursive animals on the planet.
There is, of course, a point to all this motion. Swallows feed on the wing. They are changing paths all the time to snag bugs, generally very small bugs, with their open mouths. It is a bit of a mobius strip of causes and behaviors. They have to fly and swoop around nearly constantly in order to consume enough insects to have enough energy to fly and swoop around nearly constantly in order to consume enough insects to have enough energy to…
It is a feeding strategy that works for them, though, as proven by the number of swallows in the world. (Short answer: a lot.) But all that motion can be a bit confounding for a person trying to figure out exactly what species they are seeing or, worse, a person trying to get a decent photo of them. And the other day, standing on the edge of an out-of-the-way salt pond, I was both of those things.
Initially I thought I was tracking a pair of barn swallows, because 98% of the swallows you see in Florida are barn swallows. They are awesome birds. Small – about 7 inches long and about 1/36th the weight of a coconut – but also sleek and vivacious, with silky blue feathers on their topside that gleam in the sun. But they are one of the most common birds in the world, with a range of about 100 million square miles, and found not only all over North America, but also most of South America, Europe, Asia, Africa, and a small slice of northern Australia. (They tend to spend the summer months in the Northern Hemisphere and the winter months in the Southern Hemisphere.)
It is relatively easy to track a swallow naked-eyed, but you generally don’t get enough detail to figure out what they are. Following them with the narrow field of view that comes with binoculars, it is far more difficult to stay on them. You’ll only get small, limited bits of information at a time, quick flashes that frustrate you until you learn to get Zen about it. You get the shape of their head, then their belly color, then maybe their wing shape, then a glimpse of their tail, and eventually, after a surfeit of such flashes, you can draw a conclusion, make an I.D., put a name to the thing you see ripping around in front of you. But you have to be patient.
Though the path they follow is an unpredictable tangle, it helps that the tangle will often stay contained, with the birds passing through the same bit of airspace over and over – repeatedly working the same cloud of bugs – though at a different angle, speed and attitude each time. So when you get a brief glimpse in your binocular field, then lose them when they do a hard turn near the palm tree, you might be able to find them again when they start to turn around again about 20 yards beyond that crooked stick midway down the edge of the salt pond.
Following these two birds, I picked up a little orangey-red warmth in their face, but after a few dozen glimpses in my binoculars, there weren’t any streamer-like extensions on their tail, and their wings weren’t in much of a slung-back deltoid shape, and when they fanned their tails, there were no rows of white dots near the trailing edge that looked like strings of pearls. Also, both birds had these ruddy, contrasting rump patches. Meaning they were not barn swallows.
With the blue backs and the rusty faces and the rump patches, there are two other options for swallows in these parts, both very similar looking – cave swallows or cliff swallows. The difference between the two can be a pretty hard distinction, one I am periodically capable of, then less and less capable of as time passes. It depends on how recently I’ve had to differentiate them. It doesn’t help that they are both named after geographical features that begin with the letter C.
Cave swallows tend to live only in southern Texas and northern Mexico, except for a few small colonies of them that live under bridges in Homestead. Cliff swallows are far more common, but breed in every state in the continental U.S. except for Florida. But both species are known to roam, and either could migrate through the Keys.
Some cliff swallows have bright white patches on their foreheads, which is a good field mark. Though some cave swallows have sort of ecru patches on their foreheads. Cave swallows have darker rump patches than cliff swallows. And cave swallows tend to look like they have a dark cap, as opposed to cliff swallows, which tend to look more like they have a dark hood.
It’s a muddy path, but with enough persistence it will eventually get you there. And after watching these swallows perform a few hundred circuits, and catching what fleeting impressions I could, I came to the conclusion that I was seeing cave swallows.
To be sure, I lifted my camera with its 400mm lens and started trying to catch photos of them. With twice the magnification, and however many times the barrel length, and the autofocus hunting and seeking in a bright blue sky during those brief instances when a bird was actually in frame, it was several magnitudes more difficult. And after several hundred frames, most of which were empty of birds of any sort, I managed to come up with a solid dozen where the birds were in frame and kind of in focus and exposed correctly.
Even though this whole column may seem like a long walk to rationalize why the accompanying photos are of such poor quality, I’m happy to report that I was, in fact, seeing cave swallows. At least I’m pretty sure I was.
