Tuesday 9th July 2013

Scorching temperatures, but few butterflies

This weekend saw dramatically increased temperatures compared with those of recent weeks, and I was out in my favourite areas in northern France and southern Belgium, full of hopes of finding large numbers of high summer butterflies, but still there were far fewer in evidence than I would have expected. Perhaps they are still to emerge, but it seems that the cold spring has knocked many species back quite severely.

Saturday 6th July saw temperatures of around 30 degrees Centigrade, and a thundery feeling in the air. Such conditions often cause butterflies to be reluctant to fly, and a long walk through my favourite forest produced very little, other than four Silver-washed Fritillaries, Argynnis paphia. These magnificent insects, with their bright gingery uppersides and beautiful sailing flight, are truly the kings of the summer forests.

A male Silver-washed Fritillary, easily recognised by the dark streaks along the veins on the forewing

The following day, Sunday 7th July, I headed eastwards into Belgium in the hope of more sightings. Whilst still in the car, two large purplish butterflies shot past, showing a slight yellowish tinge. These were almost certainly Lesser Purple Emperors, Apatura ilia, but I did not see them well enough to add to my list, and I did not see more. Here again the forest was lacking many of the species I would have expected, although White Admirals, Limenitis camilla, were out in some force, gliding with their splendid flight around the forest glades.

A White Admiral sipping moisture from the ground

Several Black-veined Whites, Aporia crataegi, were also to be seen, but other than more common species such as Large Skipper, Ochlodes venatus, and Lesser Marbled Fritillaries, Brenthis ino, Comma, Polygonia c-album, and Brimstone, Gonepteryx rhamni, little was showing.

One encouraging sign was that much work is being done in order to make the forests in southern Belgium more butterfly-friendly, with clearings being created, allowing the sun to reach the forest floor and wild flowers to flourish. We can only hope that these efforts will bear fruit in more favourable years to come.

A sign indicating a newly cleared area, in this case for Marsh Fritillaries, among other species

In the afternoon, I moved on to examine the chalky grassland areas nearby, but here again there was remarkably little flying, other than one Brown Argus, Aricia agestis. However, just as I was driving away, the gliding flight of a large, dark butterfly caught my attention, and I jumped out of the car. Finally, I had found at least one example of one of my target species, the Purple Emperor, Apatura iris. Unlike many butterflies, Purple Emperors never visit flowers, preferring instead mud, dung, decaying animals and other unsavoury items. This individual, a freshly emerged male, with his glistening purple sheen changing colour as it caught the sun, was highly cooperative, settling and probing the mud with his bright yellow proboscis as I photographed and filmed him for several minutes. I normally see many of both species of Purple Emperor in this area, and hopefully this was the first of many more that will emerge in the coming days.

A freshly emerged male Purple Emperor, showing how the purple sheen often appears on only one side, depending on the angle of the light

A video of this male Purple Emperor can be viewed below.

On my way back to the Netherlands on Monday 8th July, I stopped at a reserve on the Belgian/Dutch border, where I had some hopes of finding Alcon Blues, Maculinea alcon, but none were to be seen. However, there were numerous Silver-studded Blue, Plebejus argus, which are a kind of symbol of the Dutch heathlands (indeed in Dutch they are known as Heideblauwtjes, or Heath Blues). It was encouraging to see so many of these little jewels flying over the heather.

A female Silver-studded Blue perched briefly on a grass stem

2013 list total as at 9th July: 61 species

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