Monday, 20 September 2010

The Goat's Day Out

A fine, sunny, warm day and it really brought out the insects, there were butterflies and dragonflies and even quite a few damselflies. Rather more remarkably there were also goat moth caterpillars. Michelle found one during the morning, it seemed injured around the head, probably attacked by a predator, but why such a large and juicy food item would have been left was unclear. As it was not very active it did make an easy picture though.
They really are very large, probably 80mm (or three inches plus) long, these are full grown and wandering about looking for a place to make their cocoon. They feed on wood in the trunks of live trees and take several years to grow. They leave the tree and make a cocoon in which they spend the winter, only pupating in the late spring of the following year. During the afternoon Michelle found another caterpillar, this one dead and missing the head, then she found a very lively one marching over the ground. I went to have a look at this and found another predated one. So, all in all, four that we found all around the same group of willows. The curious thing about the predated ones was that none had been eaten despite looking like a good meal, it made me wonder if they are unpalatable in some way. I looked up this possibility but there seems to be no mention of it anywhere, so the mystery of why they should have been attacked but not eaten remains.

It was not a great day for birds, in that there were no new migrants about. The great white egret spent the afternoon on Iblsey Water along with 3 little egrets, 4 Egyptian geese and a common sandpiper. There was also a hobby hunting dragonflies and a peregrine perched on the long shingle spit.

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