Am Bratach No. 248
June 2012
editor@bratach.co.uk



Nature’s call
by Andy Summers

My story this month starts with a big hairy caterpillar. To be precise it was a two-year-old caterpillar of a drinker moth. It was as long and as thick as my little finger, covered in long fine hairs. It was doing what caterpillars do best — munching their way through the mollinia grass and delicious sedges that cover most of the hills around here. If you have ever been walking off the path you cannot miss seeing these hirsute monsters. And if you are like me and have seen them hanging in the vegetation covered in frost in the middle of February you will be amazed how they can survive. I suppose they must have some type of anti-freeze in the blood.

The drinker moths are one of four big caterpillars you might come across in the hills. All of which spend two years as a caterpillar before hatching into large day-flying moths. Along with the drinker, they are the Fox Moth, the Northern Eggar and the Emperor Moth. Being big and hairy they do not have much to fear. Most birds find them too hairy to deal with. The great tits are one of the few small birds that will try. Indeed, I was entertained for ages recently while watching a pair of great tits, each grappling with a large hairy fox moth caterpillar. They repeatedly smashed them against the stem of the spiny gorse bush. At first I thought they were just trying to kill them but after five minutes I realised it was more likely they were trying to prepare the meal sufficiently by getting rid of all those long hairs so they could swallow them. Or maybe they were just trying to shake the toxins out of hairy caterpillars before eating them. Anyhow it took nine minutes and thirty two seconds of caterpillar bashing before they were finally swallowed. Then the great tits had to spend about the same amount of time cleaning themselves and wiping their bills.

One bird that specialises in caterpillars, and the bigger and hairier the better, is the cuckoo. The fact is that cuckoos will fly over 10,000 miles all the way from Senegal or Gambia just to come and feed on caterpillars in the North West Highlands. Whereas the population in England has crashed in the last few years we seem to have a good few with us this year. The first cuckoo that was reported to me this year was on April 22 near Achiltibuie but perhaps you know better!

Anyway my story starts while I was watching the drinker moth. I suppose it was just a coincident that its most feared predator happened to fly past. I trained my binoculars on the fast flying cuckoo. Its distinctive long tail trailed behind as it flew over the reed bed at Clashmore. A host of little meadow pipits and sedge warblers followed in the cuckoos wake, mobbing and harrying the large invader. Deep in their psyche they probably know that cuckoos are bad news and their nest of eggs is not safe when a female cuckoo flies over looking to offload its youngster on some unsuspecting foster parents. As we all know, once hatched, the cuckoo chick ejects the legitimate occupants and then gets fed by its new and unsuspecting foster parents — true masters of deception. It is said the cuckoo’s hawk-like plumage helps them avoid attacks from wee birds whose nests they are trying to invade, but today it was not working.

And then a real raptor arrived and total mayhem broke out. But the raptor was focused not on the meadow pipits but on the cuckoo itself. The tables had turned and suddenly the cuckoo was in deadly peril. A large female peregrine will easily kill and eat a cuckoo. They can fly at 60 miles-an-hour in level flight and stoop at speeds up to an incredible 200 miles an hour. The cuckoo didn’t stand a chance, or so I thought. The cuckoo did the only thing it could and flew straight upwards into the sky, gaining height all the time. Peregrines are not designed to fly upwards but this gave the cuckoo a slight chance. I tracked the cuckoo as it got higher and higher into the sky. Caught in the drama of it all I realised I was not breathing. Despite the clever cuckoo tactics, the peregrine was gaining fast and it looked certain to catch the cuckoo when something happened.

Whether this was a voluntary action I will never know: but next thing I saw was a streak of white eject from the back of the cuckoo. The peregrine was moving so fast it could not make any evasive manoeuvres and got a face full of cuckoo guano. The peregrine banked sharply away and who would blame it and the cuckoo escaped to live another day.

Then everything went back to normal. The caterpillar kept on munching, the peregrine went to the nearest crag to cover its embarrassment and clean itself off and the cuckoo went over the hill in search of more caterpillars and perhaps an unguarded meadow pipit nest. Such is life in the May in the North West Highlands.

Andy is a senior Highland Council countryside ranger, based at Lochinver.

 

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