Butterflies, Moths and Moorhens

We are now in deep Autumn and, although the Met service will declare the first day of December the start of Winter, usually winter does not take effect until after the Winter Solstice. For the first time in many weeks I spotted a butterfly basking in the sun, albeit on an unseasonably warm day. It was a Small Tortoiseshell (Aglais urticae), a species which hibernates:

With any luck this one will also be basking in the sunlight of next spring. I observed it for quite a while and watched as it finally entered an old wooden nest box. Hopefully it will vacate the premises before any spring breeding birds move in and eat it.

While butterflies more properly belong to the warmer months there are moth species which only appear in autumn. One very handsome species which you might see, and which will soon be finished for the year is the Feathered Thorn (Colotois pennaria)  – the male has antennae that resemble feathers:

   In August I was in the Herbert Park in Dublin when I spotted a family of birds which are common in Wicklow, but almost impossible to see here because they are so shy and the ponds and lakes they inhabit are often on private land. These birds are Moorhen (Gallinula chloropus) and, incredibly I saw young chicks and was able to record them over a period of months as they grew to full size – here is the video I made about them and I hope you enjoy it:

Autumn Geese and a natural mystery

Autumn came in very slowly this year, but it turned quite cold quite quickly. However, now at last we are getting rain in proper autumn levels. We had proportionally very little rain all last winter, spring and summer. Finally the geese have started to arrive too. Here are two of the most common species, the Brent Goose (Branta bernicla):

and a flock of Greylag (Anser anser), with two Rooks (Corvus frugilegus) providing a sense of scale:

All of these birds are pictured at the famous Kilcoole Breaches and nature reserve.

There have been two noticeable trends this autumn – firstly there have been far less spiders than you would expect on average, particularly House Spiders. But all species seem to be lower in number than usual. The only spider species at normal levels, or apparently normal levels, has been the Garden Spider (Araneus diadematus), which is also the most obvious autumn spider:

    Conversely, there has been a population explosion of Brown Rats (Rattus norvegicus) which has been attributed to the long hot summer and the summer heatwave of May, June and July which almost led to a severe drought. The increased population of Brown Rats very likely has reduced the number of spiders, as rats and mice will happily eat large spiders. More rats equals less spiders.

However, from my own observations I disagree that the summer heatwave is responsible for the population explosion of rats – back in March, during the heavy snows, there was a massive surge in rat numbers. They were especially attracted to bird feeders. The winter had been very cold even before the snows arrived late, and it seems that this factor drew rats from the countryside towards human settlements in order to find food and warmth. But whatever the exact cause, there were a lot of them around, although numbers at last seem to be returning to normal: