Big cat diary, Orkney-style

By Graeme Walker

In Orkney, we tend only to have about 10 species of breeding butterflies, and one of these, the Dark Green Fritillary, hasn’t been seen for some years, likely due to loss of its preferred habitat. Orkney does, however, have lots of moths. The problem there is that I don’t particularly like late nights or early mornings, so rarely see the flying adults unless they’re a daytime species. All that said, the caterpillars of both butterflies and moths are frequently encountered whilst ambling about the footpaths of these isles, so it made sense to prioritise a caterpillar ID book rather than a butterfly/moth one, so I could at least know what would be flying around if I was awake. Well, it made sense in my head. The enthusiastic mothy folk in Orkney often post photographs on the local online insect group, including amazing images of some really spectacular hawk-moths. These are all large and distinctively marked or coloured, the sort of insect which could make your day!

When looking for a particular species of caterpillar, it is important to know which food plant it prefers (hey, we all have favourite dining establishments), as this increases the chances of success. Theoretically, at least.

So, I have spent years staring at willows in Orkney, all in vain, in the hope of a big cat. I guess what I really needed was some expert help. Someone who was better at finding caterpillars than I. Serendipitously, a smart male Blackbird frequents our garden, and the other day, we noticed him emerge from the willows with a big, juicy caterpillar. And I do mean big, and very green, the sort of green which would make a caterpillar almost indistinguishable from a willow leaf.

The following day, we spotted the Blackbird again, popping out of the willows onto the lawn and devouring a big green caterpillar. Armed with the knowledge that they’re in there, somewhere, we decided to try once more and gave the willows a proper thick coat of looking at. Is that one? No, it’s a leaf. Gah! How about that one? Nope, leaf. Grrr! Oh, hang on, what’s that?!

A mixture of Willow species
An actual caterpillar!
Big and green…
and presumably quite tasty if you’re a Blackbird

Joy unconfined! A big green caterpillar! Referring to the afore-mentioned ID guide, we figured out that this was the larva of a Poplar Hawk-moth, which unsurprisingly feeds on poplars, but also aspens and willows. This was what the Blackbird was gorging upon and we were now feasting our eyes on one.

Another one today!

Fortuitously, several years ago, I did see an adult Poplar Hawk-moth at Hoxa whilst looking for dragonflies. This was presumably a recently-emerged individual which had climbed up onto the vegetation from its pupa in the ground.

An adult Poplar Hawk-moth

Could we now hope to see these impressive insects in our garden? Not if the Blackbird has anything to do with it, we won’t.

Categories: Science

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