Dicing with danger…
Garden birds have to constantly make judgements about risk if they want a free meal
Ididn’t see the sparrowhawk, but the birds around my bird feeders did. In a moment, the sparrows, blue tits and the rest disappeared, whizzing in every direction. The hawk had come and it was every bird for itself.
Sparrowhawks are ambush specialists, but on this occasion the element of surprise failed. Soon after the predator had moved on, its potential victims were back at the feeders as though nothing had happened.
Sparrowhawks usually get the lion’s share of the blame for declining songbird populations, with generous portions also going to magpies and grey squirrels.
Garden birds have to be constantly making judgements about risk and reward. A robin visiting a bird table knows a cat could pass by, but a free meal is a sure thing.
For most songbirds like robins, blackbirds and the like, the sparrowhawk is just one of the predators they have to worry about. Other birds of prey can pose a threat, too. Then there are also the predators that raid nests to get eggs and nestlings. They’re mostly other birds (magpie, great spotted woodpecker, carrion crow and jay), but mammals will dip into a bird nest as well.
So, all those potential predators must make for fewer prey, mustn’t they? The answer is no because the relationship between the two is more complicated. If predators were to eat their prey to extinction, they’d soon go the same way.
Ornithologists have looked at bird census records from nearly 40 years to see what was going on. They found that there was no ‘statistically significant’ connection between an increase in the number of predators and declining prey populations. In fact, the number of predators has gone up as prey numbers have risen. The strength of songbird populations is about things such as the way land is farmed, how woods are cared for and the quality of the water in rivers and streams. Healthy habitats are most important, both for sparrows and sparrowhawks.