Posted: Monday 5th June 2017 by Twheatear

Birds benefiting from one another...

Usually, garden birdwatching is about the behaviour of common species, rather than the arrival of rare ones. But sometimes you get both.

This afternoon a loud, ringing call, clearly audible through double-glazing, announced the arrival of a green woodpecker. Not a particularly rare bird but - unlike its great-spotted cousins, which live close by - it only visits us a couple of times a year. And it's always a spectacular addition. The attraction is the ant nests in the lawn and, sure enough, soon this bird was down on the ground pushing its beak into the rain-softened earth. Invisible underground, its tongue would have been stretching a further 10cm, sweeping up tasty ants and larvae.

This obviously upset the ants, which spread out on the lawn to defend the colony. At this point two blackbirds - an adult and a juvenile - settled down on the grass near the woodpecker. As the ants swarmed over them, the blackbirds "preened" them off their feathers. Even more remarkably, they clearly understood the cause of the ants' behaviour, because when the woodpecker moved up the lawn to another nest, the blackbirds followed and settled down at the same distance as before.

"Anting" is a common enough technique used by green woodpeckers: sometimes rather than digging into a nest they'll simply sit on it with feathers splayed and wait for the defending ants. In a bird that eats ants anyway, this seems likely to be an easy way to get a meal. But I've never seen blackbirds doing it. There seem to be a number of possible explanations: maybe the birds use the formic acid that angry ants spray around as an insecticide, or maybe ants are more palatable food once they have wasted the acid.
 

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