Sparrow

Kim Todd

• Editore: Reaktion Books
• Anno: 2013
• ISBN:
  9781861899774
• Argomento: Biological Sciences
• Categoria: Science General

Innocent. Invader. Lover. Thief. Sparrows are everywhere and wear many guises. Able to live in the Arctic and the desert, from Beijing to San Francisco, the house sparrow is the most ubiquitous wild bird in the world. They are the subject of elegies by Catullus and John Skelton and listed as "pretty things" in Sei Shonagon's Pillow Book —but they're also urban vermin with shocking manners that were so reviled that Mao placed them on the list of Four Pests and ordered the Chinese people to kill them on sight. In Sparrow, award-winning science and natural history writer Kim Todd explores the bird's complex history, biology, and literary tradition. Todd describes the difference between Old World sparrows, like the house sparrow, which can nest in a garage or in an airport, and New World sparrows, which often stake their claim to remote islands or meadows in the high Sierra. In addition, she looks at the nineteenth-century Sparrow War in the United States—a battle over the sparrow's introduction—which set the stage for decades of discussions of invasive species. She examines the ways in which sparrows have taught us about evolution and the shocking recent decline of house sparrows in cities globally—this disappearance of a bird that seemed hardwired for success remains an ornithological mystery. With lush illustrations, ranging from early woodcuts and illuminated manuscripts to contemporary wildlife photography, this is the first book-length exploration of the natural and cultural history of this beloved, reviled, and ubiquitous bird.

1 Little Brown Jobs

It’s hard to generalize about house sparrows. One of the reasons they’re so globally successful is they never met a statement about their biology or physiology they didn’t challenge. They are primed to adapt.

House sparrows appear to have the ability to live everywhere humans have set foot (except the moon and Antarctica – so far). In 1915, a newspaper reported that a house sparrow was living 229 metres (750 feet) underground in a Scottish coal mine. For company, the sparrow had a mouse, a brown rat, a slug, some beetles, flies and a pit flea.¹ Reports continued in the 1950s and ’60s, claiming sparrows in mines in Northumberland and Durham. Natural historian Denis Summers-Smith read these with interest, but it wasn’t until the mid-1970s that he was able to visit the Frickley coal mine in Yorkshire and see for himself.

Three house sparrows – two males and a female – had abandoned the sparrow community in the mine buildings at the surface in order to live 640 metres (2,100 feet) down. The miners fed them, and they persisted, staying near the electric lights and out of the larger maze of stone. Summers-Smith speculated that they came down the ‘skip shaft’, a hole used to haul carts of broken rock in and out of the mine. They built a nest on a roof support and hatched out three young, but the young disappeared. On Summers-Smith’s trip down, he saw just the male and deemed him ‘in excellent condition’.²

This subterranean life is particularly surprising for a creature so swayed by light. House sparrows, like many other birds, are governed by seasonal shifts. Their body and behaviour change depending on the length of light in a day. For example, at the start of spring, the increase in sunshine triggers the crea tion of sperm and the development of eggs. The testicles get 100 times bigger; the ovaries about 50. For the rest of the year, these parts are neatly tucked away.

As the days get longer, males scout for a promising place to build a nest. Though house sparrows got their common name nesting on roofs, they will build anywhere with a suitable crevice: drain spouts, traffic lights, furled sails, the raised plastic curves of S and O shapes on shop fronts. Human structures are not the only ones house sparrows will adopt. They’ve built alongside the nests of osprey, red-tailed hawk and the common pariah kite.³ Apparently a host with a sharp beak and talons doesn’t faze them. One ornithologist found house sparrows raising chicks in the side of a Swainson’s hawk nest in an elm, while a hawk nestling tore apart baby cottontail rabbits a few feet away.⁴

The nests themselves are messy heaps of grass or straw, a few twigs. As with so much about sparrows, nest building codes are flexible. The domed structure often has an entrance on the side, leading to a enclosure lined with hair, wool or feathers (some times yanked from other birds while still attached). The sparrows can incorporate greenery, like wild carrot, maybe to help ward off parasites. Sparrows are not always that popular with competing species, but, when not fighting over a mate, they enjoy each other’s company. Twenty or so nests can be built very close to one another, making a sparrow apartment complex.

With a nest site secured, a male without a mate starts calling ‘chirrup’. If a male shows up, the chirper defends his territory vigorously, even if it is only a few feet on either side of a given lamppost. He flies in, claws extended, beak low, wings canted back, pecking and hopping and fluttering like a miniature marionette. The viciousness of the fights has commonly been remarked upon, as well as the bird’s seeming hair-trigger: ‘Jealousy is certainly the vera causa of the sparrow’s irritability and pugnacity. This feeling is so deeply ingrained into its very being that the slightest cause will evoke it’, wrote Thomas Gentry, a nineteenth-century observer, in The House Sparrow at Home and Abroad.⁵

If a female responds by crouching with her tail up, calling ‘quee’ and drooping her wings, the male drops his wings as well and ‘shivers’ them, inviting her over. When they mate, often the male hops on the female’s back ten times or more. They often do this on the porch, on the sidewalk, in the playground, in the road, in full view, giving them a lecherous reputation.

Commentators as early as Aristotle included cock sparrows among the ‘salacious animals and such as abound in seed’.⁶ In his essay ‘On Longevity and Shortness of Life’, where he proposes that warmth and moisture are necessary to animal existence, he gives all this wanton spending of warm, moist seed as the reason female sparrows live longer than males. Pliny the Elder, the Roman natural historian, echoes Aristotle in his Natural History, published in AD 77–9, reinforcing the ties between lust and death. He calls the randy birds ‘short-lived in the extreme’, adding ‘It is said that the male does not live beyond a year.’⁷

Because sparrows were so lusty, those suffering from impotence were advised to eat them. And they did: sparrow brains, sparrow rumps and the whole roasted bird were taken as aphrodisiacs. In books of occult philosophy written by Henry Cornelius Agrippa, the birds’ obsession with mating takes a gentler turn. According to Agrippa, witches use the blood of sparrows in their love potions. Rings left in the nests of sparrows bring the wearer love.

Historically, many observers thought of Old World sparrows as monogamous with strong pair bonds lasting from season to season. A week or so after mating, the female lays between two and five whitish eggs with black speckles. A pair can raise up to four broods over the course of the summer. Both male and female sit on the eggs. Both bring the nestlings grasshoppers, spiders and caterpillars and shove them in the waiting mouths. They seem model parents.

Oliver Herford (1863–1935), Sparrow Feeding Young with Spoon, drawing.

But when DNA testing became available in the late 1980s, making it possible to learn the precise parentage of chicks in a nest, all sorts of alternate configurations were revealed. In one study of about 60 house sparrow nests, 8 per cent of chicks had a parent that didn’t belong to the nest. One male, a serial monogamist, nested with three different females in succession. Some are bigamists, mating with two females at once. One female built a nest with her son. If incest wasn’t bad enough, she cheated on him: one of the nestlings belonged to a neighbour.⁸

These complex domestic arrangements can lead to behaviour that would have shocked those touting sparrow’s parenting skills. A recent article by José Veiga in Animal Behaviour reads more like a crime novel than a scientific study. Veiga set up nest boxes in the Guadarrama mountains of Spain and noticed that the second largest cause of death of nestlings (after being snatched by predators) was infanticide. Both sexes were guilty, with ample motive and opportunity, and Veiga either observed the killings first hand, or pieced together what had happened when he found beak-shaped puncture marks on the bodies. Some times a male who’d lost his mate would go into a nestbox, peck the chicks to death, throw them out and mate with the female. In other instances a male had two nests, one with a primary partner, whose nestlings he’d feed, and another with a secondary female whom he ignored. The secondary then killed the young of the primary, earning her the help of the male at her nest. Veiga concludes that all this violence reinforces monogamy as a desirable strategy.⁹

In the autumn, flocks of sparrows gather at harvest fields to chase stray grains of wheat or corn. As the days shorten, the testes and ovaries shrink, freeing the birds of extra weight. Most don’t migrate, taking advantage of stored food and sheltered roosting spots to help them through the winter. Through the cold months, they hang out in loose groups, squabbling over seeds, taking dust baths, chirping in a rough chorus, taking refuge in roost sites when it gets too chilly and waiting out the snow until it’s time to think about nesting again. Summers-Smith notes their easy life, even when living at climate extremes.

He wrote in The House Sparrow that, outside the breeding season, ‘House sparrows appear to have plenty of spare time.’¹⁰

When it comes to eating, like nesting, house sparrows are innovative risk-takers. Though they give their young insects during the first few weeks of life, mostly they eat seeds or, if they live in the right neighbourhood, the best scraps they can find. They are not picky. Tests of the stomach contents of birds in Pennsylvania found corn, wheat, oats, millet, sunflower seeds and elm seeds; weeds like wood sorrel, panicgrass, bristlegrass and starwort; plant parts from leaves to anthers; Japanese beetles, gypsy moth caterpillars, insect eggs, spiders, aphids, mites, ticks, flies, tapeworms, ants, lice, fleas and bread. And that’s just the healthy stuff.¹¹

In New Zealand house sparrows learned to trigger the automatic doors at a bus station, giving them access to the buttery remains at the cafe inside. They perched on the sensor and dipped their heads in front of it, or flew right through the green beam of light.¹² When cars replaced horses, observers predicted a steep decline in the sparrows that spent so much time picking oats out of manure. Some vanished, but others learned to scavenge crushed insects from automobile grilles. As humans develop novel foods such as chilli cheese fries and Cool Ranch Doritos, house sparrows are ready to devour the crumbs.

They are also accomplished thieves, exhibiting a doggedness that can look, to the anthropomorphizing eye, like bravery or cor ruption. An 1885 newspaper article in Troy, New York, quoted biologis...