The rain drops lodge on the swallows wing
Then fall on the meadow flowers
Cowslips and enemonies all come with spring
Beaded with first showers
– John Clare (of the 19th century English countryside), “Wild Flowers”
Here, rain and first flowers precede the arrival of the swallows, but the basic point is the same in Novato as it is across the northern hemisphere: swallows are birds of spring and summer. Clare’s swallows came north from Africa; ours journey from Central and South America in search of nesting sites and the abundant insect food of a North American summer. In dry California, the latter is found most reliably near water, making ponds and wetlands like Rush Creek, Hamilton, and Las Gallinas the best places to see a variety of swallow species.
Swallows are sometimes confused with swifts, an unrelated group of constant flyers: swifts are even more aerial (they roost at night, but you basically won’t see them perched during the day), have a different shape and flight style (the wings are more crescent-shaped and narrow throughout, rather than the more straight but tapered wings of swallows; flight is more bat-like and fluttery), and are significantly less common here overall (except during the fall pulse of migrating Vaux’s swifts).
We have five main species of swallows in Northeast Marin, all of them fairly unique and easily distinguished, but alike in their life of rapid flight on pointed wings, snatching insects out of the air. Our tour of the local selection starts with the two “white-bellied swallows” (violet-green and tree), continues with the two “rusty-bellied/blue-backed” swallows (barn and cliff), and finishes with the underappreciated, kind of brown swallow (the northern rough-winged).
Violet-green Swallow
The elfin sea-colored swift-mover, my favorite
Identify: White underparts and green back. Compared to our other white-bellied swallow, the tree swallow, you can look for three things to identify the violet-green: 1) back is green rather than blue, 2) from above, white areas almost connect above the tail to form a distinct white rump patch, and 3) the white of the breast and chin extends around the cheeks and eyes, while the tree swallow’s dark metallic helmet covers the eyes.
I might as well start with my favorite swallow: if I can’t win you over to swallow admiration here, then there isn’t much point in my going through the whole catalog. (I go in much more detail in my full essay on the Sky Elf.) But who wouldn’t be won over by a good look at this bird? Violet-greens are a western specialty, so within the broader North American birding world, I think they are sometimes relegated in people’s minds to just a local variation on the tree swallow, their more widespread companion in the genus Tachycineta. I tend, however, to instinctively prefer the local specialty over the widespread generic model, and the case of this particular swallow strongly supports that inclination. Big time birder Pete Dunne summed up the visual relation between the two species by noting that violet-greens are “smaller, slighter, and more angular and elfin-featured” than tree swallows. I particularly like the word “elfin.” Many birds have something of the elfin in them – lightweight and nimble, more alert to the world’s magic than plodding humans – and I know of none more elfin than the violet-green swallow.
The violet-green swallow has a rather lovely-sounding scientific name, Tachycineta thalassina, translating literally to something like “swift-mover resembling the sea,” though it is very debatable whether tree swallow blue might not be closer to the average ocean color. And some might question the inclusion of “violet” in the common name, since the violet patch above the tail is not exactly prominent unless seen from just the right perspective (as in the photo above). That’s the only problem with regional specialty birds – they don’t have long-established common names and so sometimes get labelled with somewhat obscure adjectives that seem more apropos when considering the specimen in the taxonomist’s hand rather than the living bird in the field. So yes, at a casual glance, “sea-resembling” “violet-green” swallows will basically just appear green on the back.
Why else do I like these swallows beside their general elfin demeanor? I think another part of it is our shared habitat preference of fairly open mixed oak woodland. Many of the other swallows are specialists in locations near water, and while violet-greens will certainly forage for insects over nearby ponds along with the others, they are the most likely to be found in the middle of a dry woodland. Personally, I think of myself as a terrestrial creature too.
And habitat choice for summer-only birds is strongly linked to nest site preferences: barn, cliff, and rough-winged swallows all favor human structures such as bridges, overpasses, culverts, and drainage pipes, while violet-greens (along with tree swallows) nest in tree cavities. I find a cavity in a gnarled oak more aesthetically pleasing than the utilitarian bluntness and general human clamor of say, a highway overpass. Now, if you’re fortunate enough to live in appropriate violet-green habitat, this doesn’t mean they will disdain human-built accommodation – they will readily move in to nesting boxes or bird houses, which are made to imitate natural tree cavities.
If I could choose one bird to have nesting in my yard, I would choose these elfin emerald swallows, the daily sight of whom would make me feel ever more fleet-footed and agile until I too was free from tyrannous gravity and could ascend effortlessly into the unbounded sky.
Tree Swallow
The grumpier-looking white-bellied swallow
Identify: White undersides and shiny, metallic blue back. Note that the entire upper part of the head is covered by dark color, unlike violet-green swallows with their whiter faces surrounding their eyes.
The blue backs of trees swallows are less eye-poppingly vibrant than the greens of violet-green swallows. And this blue extends down over their eyes in a tight-fitting helmet, giving them an armored, rather defensive, or even slightly grumpy or malignant expression compared to the impression of wide-eyed wonderment we get from the violet-greens. Such is my unavoidable visual impression, but I readily admit that there is a great deal of unfair prejudice in such judgments and the mental life of the two species is more likely than not quite similar.
Tree swallows, as mentioned above, are widespread across the continent, breeding all the way across the northern states, Canada, and even into Alaska. We’re much closer to the southern end of their breeding range than the northern, making for a pretty early arrival (starting in February, picking up in March) from their winter grounds, mainly in Mexico. In fact, some tree swallows regularly overwinter around here (along with a smattering of violet-greens), and can be seen easily around the always reliable feeding grounds of water treatment ponds such as Las Gallinas or the Novato Sanitary ponds on the far side of Deer Island. They are in general more tied to water than violet-greens, and strongly concentrate their nest sites in tree cavities or nesting boxes near ponds or wetlands.
Barn Swallow
The fork-tailed cosmopolitan
Identify: The basic color pattern of the barn and cliff swallows are similar, with shiny blue backs, light brown undersides, and rusty patches on the throat and forehead. Barn swallows are most distinctive for their deeply forked tail, unique among all of our swallows.
The barn swallow is the most widespread swallow, and indeed one of the most widespread of all birds. Check out this impressive range map.
If I wasn’t so prejudiced in favor of elfin green birds, I would have had to lead with this species as the swallow. Their several thousand mile migration from Argentina to here suggests their prodigious powers of flight and prepares us to accept the fact that this same species has colonized the world, undertaking separate yearly migrations between Africa and Europe, India and Russia, Australia and East Asia (the South Africa to Europe migration clocks in at over 7,000 miles). They’re everywhere, and the peoples of the world have long coexisted alongside of them.
We gave them the name of “barn” swallow in English, but they’ve been nesting on human structures long before our language existed, with records of this species nesting under the eaves of our houses going back at least to classical Rome. These days, nests in natural caves are essentially a thing of the past, with handy eaves and ubiquitous irrigation for a mud supply providing location and materials for their muddy cup nests. As of today, June 30, 2018, a group of young barn swallows are making their first tentative forays from their nest approximately 20 feet from the front door of our store, suspendum tignis as Virgil said (face store, walk left, look up). Speaking of Virgil:
Nigra velut magnas domini cum divitis aedes
pervolat et pennis alta atria lustrat hirundo,
pabula parva legens nidisque loquacibus escas,
et nunc porticibus vacuis, nunc umida circum
stagna sonat: similis medios Iuturna per hostis
fertur equis rapidoque volans obit omnia curru
iamque hic germanum iamque hic ostentat ovantem
nec conferre manum patitur, volat avia longe.
Like a dark swallow that flies through the great house
of some rich lord, winging her way through lofty halls
gathering tiny crumbs and scraps of food for her noisy young,
now twittering in the empty courtyards, now by the damp of the ponds,
so Juturna was drawn by the horses through the midst of the enemy
and, flying in her swift chariot, criss-crossed the whole plain,
now here, now there, she shows her triumphant brother,
not allowing him to engage, always flying away.
Aeneid, XII.473-480
That is some classy swallow poetry, and the swallow referred to is most probably the same barn swallow we have here: a swift, constantly moving, uncatchable bird, evoked in impeccably balanced Latin verse. Now let’s lower the classiness by a few dozen notches with a different dose of barn swallow culture:
Ah, yes, the swallow, touchstone of European culture high and less high. That same bird that Arthur noted flying from Africa flies to us from South America. That same bird is incapable of and little inclined to bring us coconuts. And knowledge of that same bird may very well save your life and lead you to victory in life’s quests as Arthur later discovered when crossing the Bridge of Death.
Servant: How do you know so much about swallows?
Arthur: Well, you have to know these things when you’re a king, you know.
We live in a democracy, so such knowledge is indispensable for all citizens. And given the advances in the extent and accessibility of our ornithological knowledge, having a little more swallow education than Arthur would be probably be a reasonable target.
Cliff Swallow
The flat-tailed town-dweller
Identification: Squared off tail, light belly, distinct buff rump patch, and light forehead patch.
Cliff swallows are the most social of our common local species. While many swallows gather in general congregation around favored feeding areas such as insect-rich ponds, the preceding three species (violet-green, tree, and barn swallow) all nest in single, isolated pairs, maintaining an exclusive territory around each nest site. Cliff swallows, in contrast, nest in dense colonies of mud nests, often on the underside of bridges or highway overpasses.
This is different than truly communal nesting, such as seen in acorn woodpeckers, where various unrelated birds will help protect the food stores and raise the young of the breeding birds. Instead, these colonies are more like human villages or cities, composed of more or less monogamous pairs (the “or less” is somewhat accentuated among Cliff Swallows by the close proximity of neighbors, compared to most monogamous birds who maintain territories for the express purpose of preventing what is technically known as extra-pair copulation). This has led Stanford swallow biologist Joan Roughgarden to say that Cliff Swallows “are perhaps our closest cousins” socially, living among others of their kind, but also with a distinct family unit.
Like the barn swallow, cliff swallows have often benefited from our structures that provide them with nest sites. Some of our largest concrete ledges, however, are found above our highways, areas which clearly pose other threats. Interestingly, the number of swallows killed by vehicle collisions has declined over the past several decades, probably due to a combination of behavioral adaptation and physical evolution towards shorter wing length that enhances agility. This doesn’t mean that highways are perfect nesting sites, but it is an interesting example of the short time frame over which meaningful evolution can occur. (Read more about the wing-length study here.)
Northern Rough-winged Swallow
Scraper-wing Saw-feather, also known as The Brown One
Identification: The plainest of our swallows, with a brown back and light underside (this white generally won’t appear as contrastingly, brilliantly bright white as on tree and violet-green swallows). The least abundant of these five species, but not uncommon.
This is the most easily overlooked of our common local swallows, being somewhat less numerous and distinctly less vivid and shiny than their cousins, and having the most obscure name. Audubon discovered them, more or less accidentally, when he collected some specimens of what he thought were the similarly brown bank swallow. Then he looked closer and had a mystifying revelation: there were tiny hooks on the wing feathers. These inexplicable barbs have ever since been the obsession of ornithologists, though invisible to normal observers in the field.
Both their common name as well as both parts of their scientific name Stelgidopteryx serripennis (“scraper-wing saw-feather”) refer to a unique series of curved barbs on the edge of their wing feathers. As my favorite 1920s ornithologist, William Leon Dawson, summed up scientific understanding of this unique feature:
In the first place it has those curious little hooklets on the edge of the wing (especially on the outer edge of the first primary) – nobody knows what they are for.
We haven’t gotten much farther than that in the last 100 years. There is some speculation that it may make some kind of sound involved in courtship, as some other birds do with their wings, but we haven’t heard it. So this triple name continues to stand as a testament to our partial understanding: when I use, it I feel myself in possession of a secret arcane knowledge held only by the chosen ornithological initiates . . . but I still don’t know what they do with their saw-feather scraper-wings.
Anyways, in the old days, rough-wings nested in rodent or kingfisher burrows in steep river banks. Now, they frequently opt for drainage pipes on bridges, concrete culverts, and the like. Fortunately, our summer drain pipes don’t get much water flow. Look for them in lower numbers feeding with other swallows near ponds and wetlands, or watch for them flying into nest holes under our monuments of concrete. For instance, some easily viewed nests can be found by taking the nice new bike path that goes from the end of Grant Ave, behind Whole Foods, towards the hospital and then Vintage Oaks. A hundred yards or so from Grant will take you to the first underpass, where roughies shoot up into openings in the horizontal surface.
Header image: Barn swallow by Katsura Miyamoto.
What? A swallow carrying a coconut?!! Blimey! Well done again, Jack!
Outstanding piece on swallows! Thank you!
Outstanding piece on coconuts, er, swallows! I have lots of barn swallows building nests under my deck off the wetlands, swooping in with insect meals, and very soon my deck railings will be the pitiful sight of large fledged birds begging their exhausted parents to fly around and gather insects.