The recent Arctic weather might convince us we are still locked in winter, but our birds are not fooled. They sense the lengthening days and have spotted the first shoots and are already preparing for the frenzied activity of the coming breeding season. . .
Take magpies, always one of our most visible species, which are already showing subtle changes in behaviour. In winter they congregate in last year’s family groups (or ‘Parliaments’), but by now most have broken down into pairs more interested in nest sites and defending territories than food. Any small group today is probably a pair being shadowed by single males looking for an illicit coupling (they may form lifelong bonds, but tests show 7% of chicks are ‘illegitimate’ – about the same as in humans).
Magpies are highly intelligent and quick to exploit any new niche. This opportunism means that while most of the year they may live on invertebrates, berries and road kills, during the breeding season they readily help themselves to other birds’ eggs and chicks. The sight and sound of the anguished victims trying to fight them off over the coming months naturally upsets many bird-lovers and some link the pillage with declining songbird numbers. Indeed, Sporting Shooter magazine has just offered a £500 reward to the person who kills most magpies. In fact their real impact is questionable.
Most small birds have between two and four breeding attempts each season. The majority are always destined to fail through bad weather, inadequate food or predation (in roughly that order – and cats are a bigger threat than magpies in most gardens).
Whatever the reason, when disaster strikes, the parents immediately rebuild and lay. They need only to be successful once a season to keep the population stable. That said, some research suggests magpies do have an impact on blackbirds and thrushes (although warblers seem largely unaffected).
Whatever their vices, magpies are undeniably attractive and are probably our most easily identified and conspicuous bird – but even more so now when they are at their most vocal. Much is directed at rivals, but they are often scolding potential predators with their distinctive chattering alarm calls.
One reason is that no foliage means enemies are more easily spotted, but parental urges are more important. Sparrowhawks and cats are always a threat, but tawny owls now attract their particular ire and other songbirds are quick to join in the chorus of outrage. This is because the owls snatch a surprising number of roosting fledgelings. The racket is thus an attempt to drive the owls to find more peaceful surroundings, as far from local nests as possible.
Tawnies are far more common than most people imagine. These silent hunters are our commonest and most formidable owl, easily capable of killing young rabbits. Like magpies, they are naturally birds of woodland margins. Modern gardens, with their mix of trees, shrubs and grass, mimic this habitat. As a result, most towns have resident owls, although often these go unnoticed.
Now is the time to detect their presence, however, because they are also particularly vocal as they set up territories and attract mates. Theirs is the classic owl hoot and if you listen carefully through the background noise of the city, you may well detect one in any tree-lined area (I’ve heard them in the heart of London).