Although I prefer to release birds where they were found, taking this bird back to the yard where he had been injured was out of the question. He deserved to live on a cat-free sanctuary, with the pampered titmice that frequent our feeders. I took him out into the yard, where he could see the feeders and the other titmice looping back and forth between the woods and the yard. Then I opened my hands. He rose up, higher and higher, with a slight twist to the left wing. He flew strongly, certainly well enough for a nonmigratory bird that needs only to flit from tree to tree. He flew all the way across the front yard and lit in the forsythia, where he fluffed his feathers, wiped his bill, and fluttered his wings. Three dark-eyed juncos darted over to keep him company. He flew farther, to a thick hedge, where he set to preening his disheveled plumage with that fussy, almost disdainful air of a bird just handled. I moved closer to try to get a photo of him setting things right, and he rose up and flew right over my head, back toward the feeding station. He paused a moment in a little birch tree, then flew straight to the peanut feeder.
If I hadn’t seen it with my own eyes, I’d never have believed it. What a bird. He had the lay of the land all figured out within ten minutes of leaving my hands. People should get on with their lives so handily. When the feeder birds spooked, he rocketed into the woods with three other titmice. To this day, I peer at every titmouse I see, looking for a slight droop of the wing, a knowing glance. He’s out there; I know it, and knowing that gives me a secret smile. Titmice 1, cats 0.
Chimney Swift
High-Maintenance Aerialist
IN A TINY COTTAGE in Connecticut, crowned by an ancient stone chimney, I lived with chimney swifts. A pair nested there each year, and, for about a month and a half each summer, I could hear the muffled roar of the birds’ wings as they tended nestlings that first chittered and then yammered and then inexorably drove me to distraction with the harsh, scraping screech of adolescent chimney swifts being fed. The chimney acted as a sound chamber for the birds’ slightest utterance. I loved the sleepy, continuous twitter of the family at night, even as the occasional ruffle of their wings woke me.
The birds were largely unseen, until a rainy day when I found three naked chicks rolling about in the cold fireplace, perhaps dislodged by the water streaming down the inside of the open chimney. I took them in, warmed them, and fed them, but I knew I was out of my league with these blind, naked nestlings. When the weather broke, I made a nest from a pasteboard strawberry box, climbed onto the roof, and lowered it on strings into the chimney, as close to the level of their original nest as I could get it. I tied it securely and went back into the house to listen. A whir of wings as an adult swift entered the chimney, the unmistakable scrabble of its claws on the side of the strawberry box, and the clamor of prodigals being fed. A huge grin spread across my face, one of wonder at the birds’ flexibility in accepting my makeshift nest mixed with extreme relief at being freed from having to raise them myself.
I had no more significant contact with chimney swifts for the next twenty years. They were flying cigars; they were tiny bombers, chittering and swooping on trembling wings high overhead. I’d learned a little bit about them that I hadn’t known; for instance, their incubation period is around twenty days—a very long time, especially for a bird that hatches altricially (blind and helpless). A chicken’s incubation period is only twenty-one days, and chickens hatch covered with down, open-eyed, and ready to scratch and forage for themselves! And I’d always assumed that swifts nested colonially in chimneys, but further research revealed that one pair claims each chimney, despite what major reference books said. As many as forty nonbreeding birds may roost communally in a chimney occupied by a single breeding pair, a phenomenon that’s not well understood and that contributes to the popular supposition that the birds are colonial nesters. For birds that nest literally in our living rooms, chimney swifts are poorly known.
From the strawberry box experience, I had an inkling that swifts were something more than an unknowable avian enigma, but I couldn’t have guessed what was about to pan out on June 23, 2004, when the phone rang. A woman had a box of five tiny pink chimney swifts that had been knocked down when her neighbor’s chimney was cleaned. The neighbor had called a chimney cleaning service when she heard strange noises in her flue. I had to wonder about a chimney sweep who would take an enormous steel brush to a flue occupied by swifts. Certainly a professional sweep knows what chimney swifts are; that they’re the authors of the strange noises his client complains about; that his brushes will destroy their nests, breaking federal law. Perhaps that’s the whole point of the exercise, to clean out that which annoys.
Homeowners often assume that a bird nesting in close proximity to their living space constitutes a health hazard, and they justify nest destruction on those grounds. Paul and Georgean Kyle, North America’s leading advocates for chimney swift education and conservation, in a paper called “Environmental Tips for Homeowners and Professional Chimney Sweeps,” state that a single chimney sweep has been known to kill as many as one hundred swifts in a season. A sooty little secret, one I hadn’t thought much about before these small pink orphans came to me. It’s a mistake to assume that everyone respects federal laws that protect native birds when there’s money to be made.
The homeowner, perhaps feeling a bit of remorse for hiring a professional to come eliminate baby birds, called the squirming nestlings to the attention of her neighbor, a self-described “animal person,” the kind of person who finds herself cleaning up after the thoughtless cruelties of others. I meet a lot of “animal people,” most of them women, and I love them for the way they lead with their hearts, how they drop everything to help the helpless. There is a lot to know about caring for birds, and some birds are harder to provide for than others, which leads such kind souls to my door. If there were a scale of difficulty in raising birds, I’d give chimney swifts five stars, an Extreme rating, as I was to find out very soon.
I started out with five naked chicks, writhing in a shoe box lined with tissues. They were very young, perhaps four or five days old; another star on the difficulty scale. Before three days had gone by, I’d lost two; they’d languished and stopped gaping, and force feeding couldn’t bring them back. A third bird died on the fifth day. But the two smallest chicks clung tenaciously to life as I blundered along, trying to do right by them.
So much of what makes chimney swifts hard to care for springs from their bizarre natural history. First, chim neys are very warm places in summertime; sun heats them, and at night, residual heat from the house travels up. I realized I’d need to provide supplemental heat from a lamp, keeping the swifts at a constant eighty degrees, which would aid their digestion and mobility. Second, chimneys are dark and full of soot. Fortuitously, chimney swifts’ eyes are sealed shut until they’re fourteen to eighteen days old, in contrast to those of open-cup-nesting songbirds, whose eyes open before a week has passed.
Perhaps because chimneys constitute visual deprivation chambers, young chimney swifts show no contrasting gape flanges or mouth lining colors. Instead, their parents find them by sound and touch. And, being blind for most of the nestling period, they react only to tactile or auditory stimuli. I nudge the silent nestlings, and they chatter and gape and gobble up what I offer them. I blow on them, and the same thing happens. In their world, an arriving adult announces itself with a whir of wings, and a stream of air rolled over a fluttering tongue simulates the event. They remind me of the naked, blind, pink animals that live in caves, input-limited creatures to whom light and vision mean nothing.
Chimney swifts lead vertical lives; they perch clinging to chimney walls. Even the nestlings’ feet are incredibly strong. It’s almost impossible to disengage one from any surface without peeling each toe off. It’s no wonder—their lives depend on clinging strongly. In a chimney, falling from the nest or one’s perch onto the bricks is a death sentence, and they hang on like they mean to stay. They climb from their tiny nest well before they’re feather
ed and cling, shuffling around on the sheer wall with fluttering wing stubs.
Young chimney swifts never grow down feathers; they proceed from naked skin straight to pinfeathers, like woodpeckers do. This is another hallmark of birds that grow up in warm, protected environs. Well before their feathers break the skin, they spend a great deal of time “preening,” their bills going through precise and stereotyped motions, riffling and nibbling feathers that aren’t yet there. I’m reminded of watching my four-year-old son, Liam, arranging his hair in the mirror. Not yet at the age of self-awareness, he goes through the motions anyway. Not only are the nestlings naked but they lie in the nest with their necks extended over its rim, hanging down like five little Kilroys. When I blow on them or touch them, they chitter madly, waving their heads wildly but never raising them. It’s very difficult to feed a bird that begs with its head hanging down. I realize that, in nature, an adult chimney swift drops into the chimney, then swoops up and clings to the underside of the cantilevered nest, feeding the young from below. I’m forced to hold each chick’s head still, in an upturned position, to be able to get a loaded forceps into its mouth.
Another peculiarity I discovered about chimney swifts is an absence of fecal sacs, those membranous coatings that constitute avian diapers. In most songbirds, adults feed a chick, then wait for it to produce a neatly contained fecal sac, which is carried some distance from the nest and dropped. Swift droppings are discharged in a loose splatter but with great fanfare. A chick feeling the need to defecate wiggles its rump, backs up, clings tightly to the nest rim, and shoots the liquid droppings as far out into space as it’s able, just the way young raptors do. You might imagine that this makes them a special joy to care for. But this behavior makes perfect sense in a chimney, where there are no predators that might locate the young birds by their droppings. Thanks to their energetically expensive aerial foraging, adult chimney swifts visit the nest rather infrequently. Even if they were agile enough to do so, they would never be able to keep up with removing the young birds’ copious droppings.
I’d always wondered at the construction of chimney swift nests. I have one before me on my desk as I write. How did it hold a brood of five young? It’s tiny—only 3¾ inches across, with a cup only inches deep. It’s underslung, more a twiggy hammock than a nest, glued onto the bricks with the parent birds’ sticky saliva. I’ve watched chimney swifts gather the twigs for their nests, swooping over the tops of giant maples and oaks, snapping dead twigs off in flight with their feet. I remember my jaw dropping as I realized what the birds were up to, fluttering among dead branches protruding from the leafy canopy, right there in my Connecticut yard. They transfer the twig from foot to bill for the trip to the nest. The selected twigs are amazingly consistent, averaging 1¾ inches in length. Shorter, finer twig lengths—most around ½ inch—make up the inside base, and the twigs get longer and stouter—up to 2 inches—as the birds build the cantilevered nest outward, like a wall sconce.
It may take the swifts three to four weeks to finish building a single nest. The eggs are laid when the nest is only half-finished; the birds continue building it until the eggs hatch. A coating of dried saliva gives the nest a lacquerlike polish that allows any stray droppings to simply roll off. Debris, such as bits of feather sheath, simply drops through its open basket weave. Parasites, so common in swallow nests, have not been recorded in chimney swift nests. Holding it in my hand, with the experience of caring for messy chimney swift young under my belt, I suddenly understand that everything about this minuscule nest has to do with keeping the young birds clean, and away from their own accumulated droppings, just until they’re strong enough to climb out of it. For broods of more than four, this happens around Day 14, when their eyes have just opened.
The sticky saliva, still flexible after four years, has the plastic texture of dried mucilage. It’s got to be loaded with protein and collagen, but apparently its chemical composition hasn’t been analyzed. Edible-nest swiftlets of Southeast Asia forgo the twigs and construct the entire nest of saliva. It looks like a cup made of rice noodles. When boiled, the gelatinous saliva is a binder for soups. As are many bizarre animal byproducts, it’s highly valued in Asia for supposed medicinal and aphrodisiacal properties. I root around a little and find a scientific paper authored by Chao-Tan Guo, with nine Japanese coauthors, showing that edible bird’s nest extract strongly inhibits infection with influenza viruses; they consider it a safe and valid natural source for protection against infection. Safe for the imbiber, perhaps, but the men who climb limber, impossibly tall bamboo ladders against cave walls in Malaysia to gather it might argue that point.
Predictably, edible-nest swiftlets are becoming scarce. Bird-nest merchants in Vietnam, Indonesia, and Thailand have started to build houselike structures in order to attract wild swiftlets. The most highly prized nests are white, made entirely of swift spit, free from feathers. Climbers destroy imperfect nests, along with the eggs inside. The theory is that this selection process favors birds that produce feather-free white nests for the trade. When I think about swift saliva, the last thing I think about is preventing flu, or aphrodisiacs. I think about baby swift droppings, about adaptations to life in odd places. It’s a weird world.
Keeping the babies warm seems to help their vitality and appetite, which isn’t at the level I’d like to see. But I worry that the heat lamp is causing them to get dehydrated. I decide to administer pediatric electrolyte with a dropper, and I’m amazed at the upturn in their condition. I follow every feeding of mealworms and crickets with an eyedropper shot of electrolyte. Their appetites pick up. I learn from another rehabilitator that dehydration is the main cause of anorexia in baby birds, and chimney swifts seem to need more water than any other bird. I guess flying insects must be high in water, just as they are low in calcium; I roll the baby swifts’ crickets and mealworms in calcium before feeding them to the birds. I jettison the heat lamp and start sheltering the birds in a beer cooler with a jar of warm water beside them. It keeps them at a steady temperature without dehydrating them, and closing the lid gives them the darkness they seem to crave. Blindly feeling my way through my cave of ignorance, I’m hitting on the strategies I need to keep them alive. I’ve got only two left to learn on. I venture to name them: Sasha and Amelia.
Adult chimney swifts have a distensible throat area—the gular pouch—which they cram with small flying insects, making a nickel-size bolus of protein that is easily carried in the bulging throat. You wouldn’t want a wad of insects hanging out of your bill when you’re ripping along at seventy miles an hour. I notice that the babies have strong tongues that they can use to lick out the corners of their mouths—something I’ve seen no other small bird do. My macaw licks the corners of his mouth and even the outside of his bill, but his tongue structure is utterly different. It’s a bent, fingerlike organ, not the flat ribbon that constitutes most passerine tongues. It occurs to me that the adult swifts might use this strong tongue to divvy up the bolus of food between as many as seven babies. By the sixth day, a parent will disgorge the entire bolus to one nestling.
It’s touch and go feeding the two remaining birds. They alternate, first one refusing food, and then the other. I’m consumed by worry that they’ll die, too. I consult on the telephone with Astrid MacLeod, an experienced bird rehabilitator, who advises me that the pediatric electrolyte I’m using to rehydrate the birds might be robbing them of water because it’s so high in sugar. She explains what’s going on at a cellular level and advises using plain water. I’ve concluded that flying insects must have a much higher water content than mealworms and that parent swifts must have some way of bringing water to their young that I know nothing about. I’ve never seen young birds need so much water; in fact, I’ve raised most birds without any more water than is in their moist formula. If only I’d known about their water requirements, I’d be raising five. It bothers me to think that simple dehydration was killing them.
Next to Astrid I feel like such a pik
er, more of a witch doctor than a scientist. I look around at my house, ankle-deep in the kids’ toys. I haven’t had time to pick them up, to go to the grocery store, to do any of the things I do to keep the house running and livable. I’m mixing sloppy batches of bird formula, grinding kitten chow, adding pinches of calcium and vitamins, washing eyedroppers, feeding the birds every forty minutes from predawn dark to bedtime. It is all-consuming, and it’s depressing to teeter on the brink of failure, to wonder what I’m doing wrong. Yet, I’ve gotten them to the point of feathering out.
By July 2, things have settled down. With copious supplemental water, Sasha and Amelia are begging and chittering for food. I learn to look at their droppings to see if they’re getting enough water, and I notice that drier droppings tend to go with anorexia. I relax and begin to enjoy my role as chimney swift mother, even as I chafe at the enforced confinement of having to drop everything once an hour. The fun part is about to begin, and this odd job I’ve taken on will get much more demanding before it gets easier. I’ll have to provide proper housing for these birds, and it’s not going to be a strawberry box or a parakeet cage. These birds are aerialists, and I’m going to need a big cage. Not only that but I’m going to need something that approximates a chimney for them to roost in when they’re not flying. I’m going to have to add a sixth star to their difficulty rating.
The Bluebird Effect Page 10
