Are you feeling fall in the air? Sun setting earlier, not as hot at midday, with yellowing leaves blowing down in a sudden beeeze, thistledown drifting across a dry countryside? You likely have your own set of signs that summer is winding down, but I expect most Dawn Chorusters share one: the departure of their swallows.
We all see many summer migrants, but there’s something especially iconic about the swallows. Their busy darting and swooping, skimming and flitting, chirring and twittering is enlivening (even exhausting!) to watch all summer. They fill the days, almost like a brightness in the background…. we get used to it, until one day notice it’s quieter. For me that was a few days ago. So this week I’m showcasing these special summer visitors, before they have all departed for their homes down south.
Swallows are aerial insectivores, a lifestyle that requires quick maneuverable flight. Their supercharged activity is possible due to long thin wings and a streamlined body shape which uses energy very efficiently: “Metabolism during flight in hirundines (swallows) and swifts...is 49.3%–72.6% lower than other birds of similar size. (www.sciencedirect.com/...)”.
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Their eyes are unique for a songbird, actually more like the vision of raptors, physically and functionally, an example of evolutionary convergence (www.journals.uchicago.edu/...) in two very different bird groups who both chase prey on the wing. But their beaks are adapted to catching and holding awkward-shaped insects: short, wide and strong. They’ll catch whatever’s out there, although they prefer single big insects over swarms of tiny ones given the opportunity. One study of swallow diet across North America found they eat 40% flies (crane flies, horseflies, robber flies etc), 16% beetles, 15% true bugs and leafhoppers, 13% bees, wasps, and ants, 4% dragonflies and damselflies, 2% butterflies and moths, and 1% grasshoppers and crickets. (birdsna.org/...).
But a reliance on insects means they can only be up here in northern latitudes in summer. Swallows must depart in good time before the insects die off with the coming of cooler fall weather. Between their arrival in late spring and now, they must nest and raise families. It’s a very busy season.
In my part of the Pacific Northwest, I see mostly four kinds of swallows. The general information about them below comes from Cornell’s Birds of North America site (birdsna.org/...).
Violet-green swallows (Tachycineta thalassina)
These return earliest in spring, typically by the end of March, and I see more of them around my house than other swallows. While they feed over ponds and fields like the rest of the swallows, they nest in the woods, and my house is surrounded by trees. V-Gs are secondary cavity nesters, meaning they typically nest in natural holes or previously occupied woodpecker nests in coniferous trees. Their gleaming deep green back contrasts with a bright white underside, displaying shifting light and dark as they swoop around after bugs. I haven’t seen any V-Gs since the first week of August. They winter in Central America.
Northern Rough-winged swallows (Stelgidopteryx serripennis)
The name for these swallows comes from the serrated edge feathers on their wings but that’s impossible to see from a distance. I know them as the swallows who nest in burrows dug into the clay banks along two nearby beaches. I’ve been watching them return to nest in the same holes year after year, this year first appearing the second week of May. By mid June there were at least three active nests in this clay bank nearest my house. Roughwingeds are not as colorful as other swallows but I love watching them come and go across the water and down the beach. I last saw the last RoughWingeds coming and going to their burrow a few days ago. These swallows also winter in Central America.
Barn swallows (Hirundo rustica)
The most widespread species of swallows in the world, Barn swallows are in some places known as just Swallows. Barn swallows are such successful birds they routinely hatch out two nestfuls of chicks each summer (other swallows only nest again if their first is lost). They have time for it, arriving in April, and leaving here last, sometimes into September. They forage low to the ground, the most productive zone for insects, edging out other swallows. But perhaps the feature that really explains their success is how closely associated they are with human development. Barn swallows forage in pastures and fields, and nest in human structures, building mud cups against the walls. They also like having power lines and roof ridges to perch on. In my neighborhood hundreds of Barn swallows nest every year in an abandoned fish processing building across from my favorite beach. Surrounding it are 20 acres of fields, wetlands and small ponds — nirvana for swallows. They’ll even hop around on the beach, going after sand fleas and picking up bits of shells for their gizzards. Most of Barn Swallows have disappeared in the past week but I’m still seeing a few. They have a long flight home to South America.
These three kinds of swallows are reliable visitors every summer. The fourth is more intermittent, with a locally strange story...
Purple Martins (Progne subis)
Martins are the largest North American swallow. Up until 60-70 years ago they were abundant in Washington, but their population crashed when starlings and House sparrows moved in. Those birds steal Martin nesting sites, destroying eggs and chicks. In the past couple of decades birders and birding organizations have set up special martin nesting boxes in over-water sites like pilings and docks which the martins have taken to enthusiastically. The 30 nest boxes at the Anacortes ferry dock put up by the local Audubon society have been fully occupied the past 15 years. Their numbers are even increasing in my county although I never saw a Purple Martin in my area until a few years ago. The circumstances were unusual! I think you’ll agree.
Two years ago while kayaking around in my local bay I saw a pair of Martins coming and going from a derelict sailboat. On closer inspection I realized they had nested in the hollow metal boom! Perfect size for them and a few hundred yards from shore so no starlings, House sparrows, raccoons, or other predators could attack the nest. I watched them crossing the water — high up as they do, a characteristic of martins — with dragonflies and other insects captured at a wetland pond. My delight turned to horror one day when I arrived at the bay to find the sailboat being towed away. It had dragged anchor and run into another boat, whose owner reported it. I knew the nestlings hadn’t fledged yet and could only imagine the distress of the parents watching their nest disappearing out to sea. The boat reappeared a few weeks later but there was no sign of Martins by then on shore or on the boat.
Last summer the boom nest went empty.
Nor did I expect much this year — why would birds attempt to nest at a disastrous site? Typical life span for Martins is 5-7 years. They’d remember.
But on a kayak excursion this summer, on July 12, I saw a pair of Martins at the boom!
I didn’t actually see them carrying insects but they did crawl into and out of the boom opening. A promising sighting right? Well, not so fast. See, the sailboat was in use this time, some guy was living on it. Or maybe not.
Some backstory: I’m not sure who owns this boat, have heard rumors an earlier owner had “died of drink” and that the boat inherited by family uninterested in sailing. It’s been anchored out there for decades, moldering away, bottom fouled, permagrime on all surfaces, sails cracking and moldy. Too bad, it was once a pretty thing.
On June 30, I saw a mention on FB of a member of the purported owners coming up to live on the boat, his mother’s attempt to get him away from his drug scene. On July 1 there he was, hauling supplies out to the sailboat. The kid spent two nights on the boat, then tied up his skiff to the No Trespassing sign on the beach, and I haven’t seen him since. So you can imagine my concern when I saw the Martins in the boom a week or so later...what if the kid came back and disturbed them?
I thought the situation couldn’t get more dire but it did. The absentee property owners whose No Trespassing sign was used as a tie-up returned for a visit a couple of weeks after that and were not at all pleased to find the derelict skiff partially embedded in the sand by then cluttering up their beach. Evidently they reported the sailboat to the county as derelict. I’d been watching the boat daily through my zoom lens, monitoring the Martin activity, and in early August saw a notice newly ziptied on deck. The next day, August 13, we went out in the kayaks to take a closer look. I discovered three things:
1) the green sleeping bag blown to the end of the boom on a windy day had NOT covered up the opening to the nest (whew),
2) the notice informs the owner that if the boat isn’t moved by Sept 6, the county will take possession and sell it,
and,
3) the pair of Martins were in full swing feeding and caring for nestlings.
Now what?! Sources say Martins fledge 30 days after hatching. If the owners never come back, the birds will be home free, for this year anyway. How do I know? Martins eat nestling fecal sacs for the first week, and I saw mom Martin hauling away a fecal sac, meaning they’re at least into week two.
At the very most, the nestlings had three more weeks from then, fledging approx by Sept 3. I’ve continued to watch the boat and as of a few days ago there’s been no sign of Martins out there. Nor am I hearing their distinctive warbling chortle, deeper than the typical swallow call. Could the activity in mid July have been incubation, so that nesting wrapped up by late August?
The Purple Martin family appears to have departed south, heading for South America. Will I see them next summer, and if so, where can they nest?? The sailboat will be gone. I’ve been thinking about asking around of the local dock owners whether they’d be open to my putting up a nest box. Likely a hard sell, but maybe I can get something going. It would be wonderful to make this bay a welcoming summer home for Purple Martins.
As you can tell, the swallows in my neighborhood are a summer drama, exciting and enlivening. Their aerial acrobatics and flashes of color and pretty warbling brighten up the season. It closes down so quickly! Only a few Barn swallows remain, and not for long. The migration of the swallows is a farewell to summer.
What swallows do you see in summer? Have they departed yet?
Time for your birdy observations of the week.