Unusual visitors make it to our shores

“THERE’S A hummingbird hawk moth on the patio!” I burst into the house to spread the exciting news.

Actually the rest of the family weren’t that excited, but they duly trouped out to have a look.

For a few minutes they admired the brightly-coloured insect as it hovered in front of the petunias and fuchsias in the hanging baskets.

They said that it did remind them of a smaller version of the hummingbirds we’d seen in Central America a couple of years before. Then the moth buzzed off.

When I lived on the south coast I saw these moths quite often but this was the first one to have visited me in the midlands. They’re a migratory species based in Southern Europe and North Africa, and, most years when they reach the south coast of Ireland they don’t bother going much further, though there are occasional records from as far north as Finland and Iceland.

As hawk moths go, they’re not huge but they’re unusual because they’re on the wing during daylight hours. They hover in front of a flower, uncoiling their long tongue to get at the nectar inside, and while they’re doing this their wings beat so fast you can’t actually see them. This is very similar to the way hummingbirds feed from flowers or from special feeders filled with sugar solution.

There’s something rather wondrous about migratory insects, particularly ones that make it to islands as isolated as Ireland. I have seen red admiral butterflies twenty kilometres out to sea, determinedly fluttering towards the Irish coast, having presumably taken off in France or Spain.

The record for this kind of thing is probably held by quite a small and frail-looking moth called the silver-Y. One was once spotted flying 900 nautical miles south west of the Cape Verde Islands, heading for the coast of South America, which was still 400 miles away.

This is the right time of year to look out for migratory moths and butterflies, particularly if the weather stays warm and calm. A friend of mine has already spotted a clouded yellow, one of our less common migratory butterflies, on the local canal bank.

Red admirals are our commonest migrant butterfly and possibly the brightest and showiest. In their search for the sugars they need to survive, they don’t confine themselves to nectar from flowers. They love windfall fruit, particularly if it’s started to rot, and I’ve seen them feeding on the sweet sap seeping from a damaged birch tree.

Painted ladies are not quite as common, though in some years they congregate in huge numbers on a bit of raised bog near my house. They seem to have a particular liking for the nectar from heather flowers.

Both these species travel here from North Africa and Southern Europe but they do so in two generations, stopping off to breed half way. A large and very spectacular moth, the death’s head hawk moth, is also an occasional visitor from North Africa. It gets its name from a distinctive skull and cross-bones pattern on its head and torso. Because of this a lot of superstition is attached to the species. It also has a bad reputation for robbing bee hives and an old name for it is ‘bee tyger’.

These northward migrations by butterflies and moths pose a bit of a mystery. There is no return migration so there seems to be no evolutionary advantage to them. The usual explanation advanced by lepidopterists is that they are relieving population pressure in their home range and ensuring that they can colonise new places if there’s any environmental or climatic change.

If this is true they have been waiting a few thousand years for the climate change that’s now starting to happen.

* dick.warner@examiner.ie

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