5 December 2009

Defending a Territory

“I own that I love the blackbird,” says one nineteenth-century writer: an easy confession to make. But who will speak up for that other black bird, the carrion crow? From time immemorial it has been called villain, associated with midnight and the darkest deeds. It seems to have a penchant for the graveyard and the cypress. It is drawn by the smell of death. One New Year’s Eve, at dusk, I witnessed a pair attacking the eyes of a sickly herring gull, one bird leaping forward to deliver a savage and cowardly blow as the other leapt back. In ten minutes the gull was killed, and at leisure the crows picked out its brains.

Yet the gull was anyway long past hope. Left alone in the soft mud at the centre of a drained reservoir, it would have attracted a worse horror still: rats. Its time had come. The crows gave it a quicker and more merciful end.

Like undertakers, crows are always properly dressed. With them blackness reaches an art. Every outward inch is black, excepting only the small white eyelid. Science suggests that black plumage is more resistant to wear, but there is something else at work in the design of a crow. Blackness is not a true quality; rather, it indicates the absence of light. The crow’s feathers absorb every last photon, except in the most brilliant sunshine, when the mantle gives back a grudging, oily blue sheen.

A pair of crows seen like this on the soft, lush sward of the town park is a sight to be prized. The two birds have been faithful to each other for several years now. In the early spring they usually build on a previous nest, high up in the fork of one of the red oaks. There, safe from small boys and the thousand disturbances below, the female alone incubates the single brood of four or five young. She is fed and protected by her attentive mate, who later supplies the food for her to give to the nestlings. At a later stage he is allowed to feed them too. A month or so after hatching the young ones fly. Until autumn they remain with their parents, learning the business of being a crow, and then are driven off.

A crow cannot breed unless and until it has a territory. In size territories vary from about 35 to 110 acres, defended most vigorously at or near the nest site. The immature birds, once expelled from the family group, have nowhere to call their own. They join a wandering gang made up of other young birds and rootless adults. This non-breeding flock lives on the fringes, continually invading the territories of the breeding pairs.

Birds holding territory dominate those that do not. Males dominate females; to the male of the pair falls most of the work of defence. Single invaders are usually easy to expel, but when there are more, the female must join in as well. If the intruders become persistent the home birds must use their full armoury of threat postures, cawing displays, aerial chases, and the technique of supplanting, or dislodging the intruder from its perch. Disputes rarely come to blows, but it can be weary work for some pairs and their health and breeding success suffer as a result. In winter the non-breeders fly off at dusk to join the communal roost of rooks and crows in the woods, but the home birds must remain behind till darkness is almost complete, and in the morning they must get up fifteen minutes early to hurry back in readiness for the day’s defence, signalled by a rolling peal of krahs from the topmost twig of the highest tree.

There are moments of peace, however, and, at the edge of the territory, our birds tolerate and are tolerated by their territory-holding neighbours. The neighbours are less of a threat than the feckless ruffians of the non-breeding flock. The territories even overlap to some extent in a common region – like that by the asphalt path where a woman is pushing her twins in a double buggy. The crows watch from a distance, with a mixture of suspicion and disdain. They have been digging for invertebrates, and by the rustic shelter a little while ago they found and ate the remains of a cheese and chutney sandwich.

The woman and her nestlings draw nearer. There is no real need, but for appearances’ sake the male crow takes wing. Followed by his mate, he flies low for fifty yards and pitches on a fresh patch of ground, to see what a little more digging will bring.

(Introduction to these pieces; see all)

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