BECAUSE I like boating and fishing I spend many summer days around water.
This means time spent watching swallows dipping down to the surface of a river or lake and kissing the water at high speed.
Housemartins and sandmartins do the same thing and occasionally I see swifts doing it.
The obvious conclusion is that they’re drinking on the wing but as I watched them more closely I decided that there must be more to it than that.
Although the swallows usually only tipped the water with their lower beak occasionally they hit it with a good splash and seemed to immerse most of their bodies.
This could just be an error of judgement on the bird’s part but it seemed to be happening fairly frequently.
Another odd thing I noticed is that if I kept watching one individual swallow on some days it would dip into the water several times a minute for several minutes on end. Surely it couldn’t be that thirsty?
You would imagine that one good beak full of water would keep a small bird going for quite a while, even if the day was warm and it was flying fast.
The problem I had was that the whole thing happened so fast I couldn’t really figure out what was going on. Then I had a brainwave and went on the internet.
There I found several series of still photographs and a couple of slow-motion videos that answered most of my questions.
Yes, swallows do drink on the wing but they also bathe in flight, which explained the occasional clumsy looking splashes.
In slow motion you could clearly see them shaking the water through their feathers after they had hit the surface.
And sometimes they’re eating not drinking.
Every trout fisherman knows that during the spring and summer you get periodic hatches of aquatic insects like olives, sedges, and midges and that after they break out of their pupal shuck they rest on the surface film before they fly off.
Dry-fly fishermen imitate these insects and swallows feed on them, which explains why they sometimes dip the surface far more frequently than if they were just quenching their thirst.
Another thing I noticed at a small pond was swallows arriving in groups.
They flew down to drink one at a time while the rest of the group fluttered around above them.
This looked like behaviour designed to protect the vulnerable bird that was drinking by confusing any bird of prey that might want to attack.
The problem with this neat deduction is that there aren’t any Irish birds of prey that kill swallows.
They’re too fast and manoeuvrable to make them a worthwhile target. But there is a small, agile falcon called the hobby that specialises in them.
The hobby is migratory and, although it’s a rare visitor to Ireland, it intercepts the swallows on their journeys to and from this country.
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