May
May is a glorious month. It is the first month of summer, although the locals love to recall the year when it snowed on Mother’s Day and to predict the same for the current year. Despite the ever-present hazard of yet another wintry blast, this is the time when the trees come into leaf, and the forbs and grasses shoot up so fast that one can almost see them grow. Butterflies, bees, and other insects are on the wing, many sampling the nectar of early summer flowers. Everywhere, birds are singing at full volume, and many species are already fully engaged with the complexities of building nests and incubating eggs; by the end of the month, some are busy feeding their young.
The four essays for this month celebrate the lives of various vertebrate animals. I start with two regular arrivals to our backyard in early May: the chipping sparrow and the white-throated sparrow (“Hurrah for LBJs”). Both are unremarkable to look at—they are exemplars of what birders call “little brown jobs”—but their biology is very special. Then I take the opportunity to celebrate a mammal that is with us throughout the year but we rarely see: a porcupine, spotted in the local forest during the second week of May (“It’s a Porcupine”). Onward to “Snakes”—creatures that spend the winter hidden away, usually in burrows below the frost line, and return to an active life aboveground in the spring. Finally, I circle back to birds. As I have already mentioned, the focus of most birds’ lives in May is on their nests and offspring. As for any home, the maintenance and upkeep of a nest can be a complicated business (“Feather Your Nest”).
Hurrah for LBJs
No, I don’t mean hurrah for Lyndon B. Johnson, the thirty-sixth president of the United States. I mean hurrah for little brown jobs, the birder’s term for those look-alike, drab bird species that include sparrows, buntings, some warblers and finches, and more. Please don’t stop reading here. I promise you that LBJs can be interesting.
We have LBJs all year round. They skulk in the bushes, sit high in the trees, and putter around in long grass, always leading to our fragments of conversation about the streakiness of the breast, the presence or absence of a wing bar, the shape of the bill, and the length of the tail. But at this time of year, the diversity of LBJs skyrockets. We are right in the middle of the spring migration. All those LBJs are on long journeys from their overwintering sites in the south (Florida, the Caribbean, and so on) to their breeding sites—perhaps here, perhaps in southern Canada, perhaps in the high Arctic. Species that would never live in our backyard (because it's the wrong latitude or habitat or because of the cat next door) drop down from the skies to rest and refuel for a few hours or even a day or two. Then they are gone.
With all this birdy excitement, the house is converted into a luxury bird hide, binoculars and bird book at the ready on the dining room table. My daily thirty-minute run up and down the drive (more like an ambling trot) and our daily tour of the backyard to admire the violets and red maple flowers may be postponed or even canceled because an LBJ is enjoying the backyard pitstop.
One of the many fun aspects of the spring migration is that the species vary from year to year. There’s so much chance in which species happen to find our yard. In all this uncertainty, two species are regulars: the chippies and the whitethroats. Both are sparrows, meaning New World sparrows (family Passerellidae), which are not closely related to the Old World sparrows, such as the house sparrow. There are forty-two species of Passerellidae in the US, and all are LBJs.
Let’s start with the chippy—or, more formally, the chipping sparrow (Spizella passerina). Over the last ten days, we have welcomed little flocks of migrating chippies to our backyard. About the same size as the European tree sparrow (which is smaller than the house sparrow) but more slender and with a longer tail, the chippy sports a beautiful rusty brown crown and perfect gray breast. Yes, we are in the LBJ world of brown and gray. The chippies call out chip, chip, chip, with no shift in pitch or intensity, as they forage on our unmown lawn, congregate in our maple tree, and then fly off.
We don’t know where our here-today-gone-tomorrow chippies have come from. Officially, they overwinter in Florida and the Caribbean, as well as in California and Mexico, but some individuals haven’t traveled that far because they hang around much farther north for part of or all the winter, varying from year to year. Their destination is similarly unknowable. Perhaps they will fly a few miles to a local breeding site, or perhaps they are gearing up for a long journey to Nova Scotia or the edge of Hudson Bay.
The chippy thrives in edge habitats, where woodland meets open lands. Before the Europeans, these habitats would have been rather few and far between, and, in all probability, the chippy was not a common bird. The haphazard clearing of the forests for small-scale farming by individual families and small communities was a bonanza for the chippy, and these birds are still very abundant in today’s world of fragmented habitats, including many places (but not our backyard) in the Ithaca area.
The whitethroat, by which I mean the white-throated sparrow (Zonotricha albicolis), has also been much in evidence this spring. These birds are much chunkier than the chippies—and they’re bigger, too. They hop around on the driveway, scratching about at the edge of the forsythia and spirea in search of insects and seeds. The big deal about whitethroats is their shiny white throat, bounded by a thin black line. That’s rather bold for an LBJ, although it isn’t a distinguishing feature. Some of the other forty-one New World sparrow species also sport white under the chin. Unlike the chippy, the white-throated sparrow is resident in a narrow sliver of latitude that includes parts of New York State: farther north a summer visitor, farther south a winter visitor. The birds that enjoy our backyard at this time of year are the migrants. Generally, the resident whitethroats stay in the forest through the year, and we rarely see them in town.
Whitethroats are very special for two reasons. The first is their song. It is astonishingly melodious for a sparrow, sounding like Oh-sweet-Canada-Canada, or so people say. Even if sweet-Canada is a bit of a stretch, the whitethroat song is in a different class from the metallic chips of the chippy. The migrants passing through have been regaling us over the last week or so.
The other special thing about whitethroats is that they come in two head colors. Bear with me . . . this LBJ story is really good. There’s the white-striped and the tan-striped versions, meaning they sport a bright white stripe or a dull brown tan stripe running horizontally from just above the eye to the back of the head. Every year, we see the migrating white-striped white-throated sparrow in our backyard, but this year, for the first time, we have hosted a tan-striped, too. Drumrolls by lovers of LBJs!!
The white-striped is not more common than the tan-striped. In fact, they exist at almost a perfect 1:1 ratio for reasons that will soon be apparent. It’s just that the white-striped sparrow is much bolder—more willing to show its face someplace that has a cat next door. Until the 1960s, it was believed that the tan-striped birds were juveniles, but then some LBJ fans got to work. Turns out: not at all! A white-throated sparrow is born with a head that is either white-striped or tan-striped, and there is no ducking that biological fate. All the females, whether they are white- or tan-striped adore tan-striped males, which are gentle, caring fathers that look after the babies. But white-striped females are much more assertive, and they get all the tan-striped guys, leaving the tan-striped females with the leftovers—meaning the aggressive, white-striped males. The males of the whitethroat world see it all differently. They all love the exciting, white-striped females, but, as I’ve already written, these females have eyes only for the tan-striped males. Therefore, the white-striped males make do with the boring, home-loving tan-striped females. Where studied, 95 percent of all pairs are between birds of different head stripes. Good thing, too! White–white pairings argue so much that they neglect the babies, and tan–tan pairings are so laid back that they are chased off their territory before the young are raised. Some people like to describe this setup as “the four sexes of the white-throated sparrow.”
The chippy and whitethroat are just the start. Our bird list for the backyard and recent walks is bulging with LBJ sparrows, including the song sparrow, swamp sparrow, and white-crowned sparrow, as well as LBJ warblers, flycatchers, and finches.
If one is prepared to pay attention, this is the time of year to enjoy the LBJs in all their understated diversity.
It’s a Porcupine
We had been chatting vaguely about visiting a preserve that is said to harbor a thriving population of porcupines. The chat was vague because the site is about an hour’s drive from home, mostly on tedious, busy roads. There’s also a low chance of seeing a porcupine at the otherwise unremarkable and rather small preserve. Instead, we were continuing with our weekly springtime visits to the local Robert H. Treman State Park. The scenery and waterfalls at Treman are spectacular, the walk is a good four miles and aerobic in places, and the spring flowers are glorious. Over the weeks, we have enjoyed the ever-changing displays of hepaticas, blue cohosh, lilies, Dutchman’s-breeches, bloodroot, early saxifrage, trailing arbutus, spring beauty, and so on.
It was mid-May, and we were about a third of the way along the Treman walk. We were chatting about toothworts, the white-flowered crucifers that don’t exactly make it to the premier league of showy flowers. We were busy concluding that they were a mix of the broad-leaved and cut-leaved, but not the slender, toothwort. Over this stretch of the walk, the gorge drops steeply from the path down to the creek at the bottom—so steeply that we looked straight into the top canopy of trees on the creek side of the path. Our toothwort conversation was halted midsentence by a dark brown, bushy structure on one of the top side branches of a hemlock tree. This strange thing was mostly round, but it was haloed in pale brown spikes and had an almost black extension pointing at about 45 degrees downward in our direction.
A quick check with the binoculars confirmed that we were observing a porcupine that was facing away from us, across to the far side of the gorge. The porcupine was perfectly still and balanced, apparently secure even though the branch was very slender and moving in the breeze. It was in the same spot when, later, we were retracing our steps back to trailhead. It hadn’t moved at all. To the human eye, this was a decidedly precarious place to snooze the day away, but clearly the porcupine saw the world differently.
A good place to start describing the porcupine is its spiky halo of quills, distributed all over the back and sides of its body. The underside and head are quill-free, with just soft brown fur. Porcupine quills are modified hairs and adorned with many tiny barbs that point backward. If we had disturbed our porcupine, it would have raised each of its 30,000 quills by contracting special quill muscles in its skin. The mechanism is comparable to goose bumps in humans. The standard advice for anyone facing a porcupine with quill goose bumps is to back off fast. If you, your dog, or the local coyote is stupid enough to make contact, the quills are shed into the attacker’s flesh, stuck firm with the tiny barbs. If the porcupine gets seriously upset, it flicks out its tail, driving its battery of tail quills, each covered in grease, deep into the flesh of your hand, your dog’s nose, or the coyote’s tongue. The winces and wriggles of the distraught enemy drive the well-greased quills ever deeper into the body, sometimes lacerating vital organs.
Altogether, the porcupine can lead a slow, easy life because it is rarely bothered by predators—and because it is a strict vegetarian. These solitary animals like to eat tree buds in spring, summer leaves, acorns and beech masts in the autumn, and small twigs and soft tissue under tree bark in the winter. For a porcupine, there’s always plenty of food that doesn’t run away.
Porcupines do have one problem, though; they are strapped for sodium. Most plant food has almost no sodium, but, as for all animals including humans, a porcupine’s cells run on sodium. (The biochemists in our midst will say, “Ah, the all-important Na+/K+-ATPase.”) This is the reason why porcupines occasionally take a swim in search of the sodium-rich rhizomes of the yellow waterlily, an abundant native pond plant in our region. For better or worse, humans have introduced other sources of sodium that are easier to access. For example, porcupines favor vegetation beside roads that are heavily salted in the winter, which leads to porcupine road fatalities. They also like to chew on sodium-rich synthetic rubber and structures made of plywood, which contains sodium-rich glue. The occasional reports of car tires completely chewed out and outhouses severely damaged in a single night are not exaggerations.
Let’s hope that our porcupine on the gently rocking hemlock branch was dreaming of waterlily rhizomes and not car tires. If it was a female, it may have been thinking of motherhood. Porcupines mate in the fall, and the gestation period is a full seven months. The single offspring is born in May, emerging head first and fully furred but still enclosed in the amniotic sac because its quills would otherwise hurt the mother. Mom then eats the sac, and, within the hour, the baby’s quills are hard and strong, ensuring that it is well protected from the start.
I will finish with a brief note of explanation. I am writing about one species, Erethizon dorsatum, of New World porcupines. This group originated in South America, and the ancestors of this one species invaded North America when the two continents collided more than two million years ago, an event known as the Great American Interchange. New World porcupines are different beasts from their Old World counterparts, which are bigger, don’t like climbing trees, and live in Africa and parts of Asia. The Old World crested porcupine is also found in Italy, descendants of the species introduced by the Romans more than 2,000 years ago.
I find it rather amazing that two different groups of rodents hit on the same brilliant idea of quills independently, even though they lead their lives rather differently in other ways.
Snakes
We had splendid views of two species of snake during a single week in mid-May: the common garter snake and the northern water snake. To be precise, we had splendid views of mating snakes. As every snake knows, the first thing to do after emerging from a hibernating den is to procreate. Snake mating is a gymnastic affair involving intimate intertwining and thrashing about. The frenzy is induced by the female’s perfume (pheromone), which is irresistible to any nearby male. Just one male had found our female water snake, so that was a fairly restrained affair. However, there were two males fighting for access to the female cloaca during our garter snake event. Premium snaky perfume can bring in a dozen or more males. Biologists like to describe the resultant scrum as a mating ball.
Let’s start with the garter snake. It is by far the most common snake around here. When I am running on the driveway or weeding in the backyard in the summer, I regularly see one slither away. The garter snakes particularly like the flower bed by the east fence, a spot that is warmed by the sun most of the day. This species also lives very contentedly in meadows and woodlands, so long as it’s not too dry. In fact, we spotted the mating trio this week in the leaf litter just beside a path in Robert H. Treman State Park. We were careful not to disturb them. That was more for their sakes than ours because garter snakes are not venomous, although a threatened garter snake will squirt out a stinky, greasy musk from glands at the base of the tail. The strenuously attended female garter snake at Treman will, in about ten weeks’ time, give birth to a litter of up to forty baby snakes. That’s the end of her responsibilities. Her babies are independent from birth. They have to work out how to catch insects, worms, and slugs on their own.
Our other snake of the week was the northern water snake, a substantially larger and stouter beast than the garter. I first became aware of the local water snakes about six weeks after I arrived in Ithaca. It was mid-September, and the summer lake-swimmers (humans, not snakes) were starting to return to the indoor swimming pool. Every year, lake swimmers return with stories of derring-do. It can be an encounter with a wayward boat dragging an anchor; becoming entangled in weeds, rising murk, or rip tides; coming face-to-face with a giant pike fish (with eyes as evil as a barracuda’s); or getting bitten by a water snake. In my first year, I really wasn’t sure how much of this to believe, but I decided on the spot that I was exclusively going to be a pool swimmer. So far, I have kept to that decision, but sometimes I wonder if I am missing out.
Yesterday evening, we went for drinks with friends who live by the lake. We were standing on the dock. As everyone chatted about this and that, I watched a magnificent five-foot-long water snake weave its way along the surface of the lake, its head raised like a periscope above the lapping waves. That was our second water snake sighting in the week. Our first sighting was a mating pair at the soggy edge of a water channel in the Binghamton University Nature Preserve. People were walking past, not noticing the writhing passion within six inches of the path. Perhaps that is for the best. The northern water snake can be very aggressive when disturbed. It will hiss, then flatten, then strike . . . and bite. The bite is painful but not life-threatening because the northern water snake has no venom. In any case, our pair of northerns did their thing undisturbed, and up to thirty baby snakes will be due sometime in August. Like the garter snake, the northern water snake gives birth to live young.
Several other snakes are quite common in our area. The milk snake deserves a special mention because it is big—all the better to hug its prey tight, like a boa constrictor. It is called a milk snake because people used to believe that it hangs around barns to suck milk from cows. Of course, it is only after the farmyard mice. The female milk snake lays eggs, usually a dozen or so, in the soil or in rotting wood and then slithers off. Her hatchlings emerge in late summer, and then it’s their turn to slither off and do their independent thing. I should add that laying eggs is very much the standard way for snakes to reproduce. Getting pregnant, as with garter snakes and water snakes, is unusual for snakes.
Feather Your Nest
It is wise, at present, to sit at the far end of our deck table,—in other words, stay close to the house and not under the maple tree. Otherwise, you may find a strand of dead grass floating gently into your tea or a lump of wet moss landing with a thump on your plate. This is a temporary problem. Within a week or so, you may sit wherever you like.
The local difficulty on our deck is caused by a pair of robins building a nest in the fork between two branches of the red maple tree. When they started, the male came and went a few times with bits of grass or dirt in his beak, but he soon lost interest, and nest building appears to be the responsibility of the female. The outer wall of the nest is now in place. It is made of dead grass, bits of moss, and small twigs, and it looks a bit unkempt. Nevertheless, it is the inside that matters. The female robin works the nest materials into a smooth bowl by standing inside the nest and pressing firmly with the wrist of her wing. She may also add in some of her own feathers to keep it warm, along with some mud to make it firm, but I can’t see that from below. Before long, the nest will be ready, and she will lay four bright blue eggs, one a day, and then incubate them for thirteen days. All being well, we will soon have a robin family above our deck table.
This pair of robins started family life rather late (see April, “Robins”). Perhaps they had previously tried somewhere else but found that their first choice was too windy or wet, or, more likely, the eggs were discovered by a chipmunk, squirrel, or blue jay. A different pair of robins has already built their nest in a crook of the box elder tree, and they are well on their way to parenthood.
Altogether, building a nest is a time-consuming and demanding business. You might expect that, once constructed, the robins would be house proud and do their due diligence to maintain it. Apparently not. In fact, they will likely move on to a different site and build a new nest for the second brood. This is partly to stay one step ahead of the chipmunk and company, but it is also good hygiene. A bird’s nest is not only a cozy place to raise nestlings but also a warm café for parasites. Many of these parasites are equipped with skin-piercing jaws and feast on slurps of nestling blood. Some, such as louse flies, ticks, and bedbugs, wouldn’t touch any food other than bird blood. Others, such as mites and fleas, are more catholic in their tastes, combining blood with feather dandruff, bird droppings, and the debris that inevitably accumulates when four tiny birds are living close together in a nest. Then there are the other insects and mites that feed on the parasites. In some ways, a bird’s nest is an entire ecosystem.
It is also important for adult birds to practice good personal hygiene. Several times in recent days, I have seen the female robin take a break from building her nest in the maple tree. She flies down to the lawn, where she lowers herself into the ant colony by the washing line and remains completely motionless, her beak open. It looks like pure agony, and it probably is! All those aggressive ants squirting formic acid, which stings like crazy . . . but also kills off the mites, fleas, and ticks.
It is not just the robins that are busy keeping parasites at bay. As I was walking along the road yesterday, I saw a small group of house sparrows taking a dust bath. Their wings were flapping back and forth frantically, amid a cloud of dust that must have been two feet high. The tiny particles of sand and gravel clear their feathers of easily dislodged parasites and remove the dry skin and debris on which many parasites feed. A little distance from the bathing sparrows, there were two cowbirds, a male and a female, innocently sipping from a puddle of water. I wonder whether any of those dusted sparrows will be raising a baby cowbird this year.
Let’s return to our deck. There is another nest close by. In recent years, a pair of starlings has nested in a cavity of our west neighbor’s house, readily visible from our deck. Unlike the robins, which usually start afresh for each brood, starlings nest repeatedly in the same place, often after removing fouled nest material or even building a new nest on top of the old one. One morning this week, I watched five birds slip out of the hole—two sparkling black parents and three brownish offspring. They settled on the gutter and chattered, along with some whistles, then flew down to our damp lawn to hunt for worms. A starling nest is a much messier affair than a robin nest. The adults simply fill the cavity with grass, twigs, feathers, moss, fine bark, sometimes even bits of paper, cloth, and string, and then they mold out a depression in the middle for the eggs. We have also observed the parents flying to the nest with fresh green vegetation. It was impossible to identify the plants, but starlings are reported to favor wild carrot leaves and fleabanes, plants with an excellent reputation for suppressing mites and company. Despite these precautions, scientists who check starlings for parasites find that almost every bird bears ticks, mites, and lice. The lice are an Old World species, meaning that the first US star-lings that were released in New York’s Central Park brought their lice with them. . . . and the lice have hung on tight.
The starling family is decidedly noisy and messy. I strongly suspect that their days in our neighbor’s house are numbered, and they will have to relocate. Perhaps they will leave many of their parasites behind when they set up elsewhere, building a new nest for their next brood.