Friday 11th July 2014

Imperial butterflies

Last Friday, 4th July, I set off southwards from home in Amersfoort, and stopped to fill up with petrol at a motorway service station near Breda, shortly before crossing the border into Belgium. I then parked up to eat my sandwich in a McDonalds carpark…and added butterfly number 67 to my 2014 list! A small, darkish butterfly with a contrastingly silvery-grey underside was actively scooting around a row of oak trees – a Purple Hairstreak, Neozephyrus (Quercusia) quercus. This must be one of Europe’s most overlooked and under-recorded species, occurring in virtually every reasonably extensive patch of oaks, yet hardly ever coming down to feed on flowers, so seldom observed.

The weekend was an illustration of how narrow the window of opportunity to see particular species of butterfly can be. The first weekend in July is traditionally my Emperor-watching weekend, and I had set my heart on seeing both the Purple Emperor, Apatura iris, and the Lesser Purple Emperor, Apatura ilia, both of which occur in reasonable numbers in the large forests in northern France and southern Belgium that I frequently visit.

Despite my high hopes, Saturday dawned grey and gloomy, and later turned into a complete wash-out, with torrential showers and hardly a gleam of sunshine.

Sunday was slightly better, and I headed to my usual Emperor track, where several Silver-washed Fritillaries, Argynnis paphia, were flying, some males even chasing females in their extraordinary courtship flight, where the male flies around the female, up over her, then down in front of her, passing beneath her before rising again behind her.

A few tired-looking Lesser Marbled Fritillaries, Brenthis ino, were also in evidence, as were numerous Ringlets, Aphantopus hyperanthus, and a few Wood Whites, Leptidea sinapis/reali.

Finally, a powerfully flying, dark butterfly shot past me, with a slight yellowish tinge. It glided around with occasional flaps, which could even be heard as a swishing sound, and finally landed on the damp sandy gravel beside the track – a male Lesser Purple Emperor of the form f. clytie, which has yellowish markings on the upperside.

The male Lesser Purple Emperor f. clytie has a yellowish suffusion and markings

The weather was still only marginally suitable for butterflies, but I did go on to see perhaps five Lesser Purple Emperors in total, including two of the other form, f. ilia, which has white markings rather than yellow.

Male Lesser Purple Emperors of the form f. ilia have white markings rather than yellow

Pleased as I was to see these splendid butterflies, the question remained as to where their larger cousins were, and in fact the sun disappeared before I was able to locate one that day. However, the Monday morning saw me scouring the same track, which I know from many previous years is a reliable site for Purple Emperors. My first observation was of a far smaller butterfly, but one which shares the dark background with white markings in the same places, the European Map, Araschnia levana.

The Map butterfly shares the same basic pattern with the Purple Emperor

The Map is an extraordinary butterfly, having two totally different seasonal forms, the Spring generation being orangey-brown, and indeed early lepidopterists classed the two forms as different species, not realising that they were in fact the same butterfly.

The Spring form of the Map looks quite different to the Summer form

Once, and only once, I had the incredible luck to find both forms feeding on a flower-head at the same time, but sadly by the time I had prepared my camera, one had flown off. Wildlife photography can be indescribably frustrating!

Other than several White Admirals, Limenitis camilla, there seemed to be even less on the wing than the previous afternoon, and I had already turned back to return to the car, when finally a male Purple Emperor, Apatura iris, swooped down from a nearby tree and landed on the track, allowing me to observe it sucking up the mineral-soaked moisture with its probing yellow proboscis.

Luckily I saw the Purple Emperor just before leaving

Yesterday, Thursday 10th July, I added one further species to my list, the Grayling, Hipparchia semele. I found two individuals nectaring on Yarrow flowers by a roadside parking area in the Veluwe area of the central Netherlands, where the species is quite numerous. I did not attempt to photograph the butterflies as they were directly next to a parked car containing a sleeping occupant. Sometimes even eccentric butterfly-photographers have to restrain themselves!

This brought my 2014 list up to 69 species

Tomorrow I leave the Netherlands, perhaps forever, after 14 years. I shall be out of internet contact for some time, so further posts will follow once I am back in circulation.

nextpost

Monday 30th June 2014

The Cranberries

Following my ultimately successful search for the elusive Poplar Admiral, Limenitis populi, last weekend, I managed to squeeze in a brief visit to the coastal dunes that run along the Dutch coast. Here I was pleased to find several Niobe Fritillaries, Argynnis niobe. This species now appears to have disappeared from the inland Veluwe region of the Netherlands, but numbers in the dunes seem to be stable. They require areas of low, spreading bramble plants, among which they are relatively easy to find – but NOT to photograph, as they speed off immediately they are approached.

The only picture of the flighty Niobe Fritillaries I managed to obtain

On Sunday, the (virtually) annual pilgrimage northwards into the provinces of Drenthe and Friesland took place, with the aim of finding three rare species that are exclusively found in boggy areas, and all of which have undergone a massive decline and contraction in range in recent years. All of them are now only just hanging on the Netherlands. They may indeed become extinct as the climate warms, as they are all three “Boreal” species that thrive in the cooler climates of Scandinavia and northern Russia.

The first to be searched for was the rarest of the three, the Cranberry Fritillary, Boloria aquilonaris. This fast-flying species is restricted to just a few tiny, isolated bogs in the north-east of the country, and I only know one reliable site – and I knew my prospects would be even lower when I saw that a new No Entry sign had been placed next to the spot since my last visit to this minuscule bog, which harbours both the butterfly’s larval foodplant, the Cranberry, Vaccinium oxycoccus, and its favourite nectar source, the Cross-leaved Heath, Erica tetralix.

Luckily it was permitted to enter the adjacent forest track, and I managed to work my way around behind the bog, to a vantage point from which I could scan the area with binoculars. At first I was somewhat doubtful as to whether I would see anything at all, as the sun had disappeared some large clouds and only appeared briefly, and even then not remaining out for long enough to warm the place up.

Finally, after a few false alarms caused by several Large Skippers, Ochlodes venatus, whose gingery colour resembles that of the fritillary, although the size is of course quite different, I managed to locate a single Cranberry Fritillary, which I was able to watch for several minutes as it buried its proboscis into the Cross-leaved Heath flowers. No photograph could be obtained, but luckily I had photographed it well at this site in previous years – including one famous occasion when a Cranberry Fritillary landed on “its” page in my open butterfly book!

A Cranberry Fritillary I photographed here in 2005

In previous years, when it was still possible to plunge about in that bog, I had seen up to five individuals, but at least this one was better than none, and provided confirmation that the species is at least just holding on. I am glad that entry has been banned, as the site is highly sensitive to trampling…and I know from bitter experience that some photographers will stop at nothing to obtain that definitive shot of a butterfly species, while not even giving a thought to the fact that their own actions are hastening its demise.

The next species required only a short drive and a walk, but the weather was looking distinctly threatening by this time, and indeed it started to rain, and a thunder storm was raging not far away.

Despite these adverse circumstances, it was not long before I managed to spot a single female Silver-studded Blue, Plebejus argus, which later dropped down into the heather when I approached to photograph it.

The heavily pregnant Silver-studded Blue

Once the rain had subsided, a few brief gleams of sunshine encouraged me to press on to a juniper-covered slope, from which it was possible to scan the extremely boggy ground below, which was again a favoured haunt of the diminutive and inconspicuous Cranberry plant, which creeps over the sphagnum moss, unnoticed by anyone but the most careful observer. It was not long before a small butterfly drew my attention, and a closer examination revealed it to be my second target species, the Cranberry Blue, Vacciniina (Plebejus) optilete.

The Cranberry Blue was almost as hard to photograph as the Niobe Fritillary!

Like the fritillary, this butterfly is now reduced to a few tiny colonies, perhaps numbering not more than ten individuals, where it just manages to hold on. In total, I managed to spot either two or three, but not more. However, this may have been due to the unfavourable weather conditions rather than lack of butterflies.

Much work is being carried out here, specifically for the butterflies and their associated bog-land specialist species, mainly involving raising the water table, removing encroaching birch and pine trees, and linking the individual bogs to allow the butterflies to move from one site to another. We can only wait to see whether such measures prove to be effective, or whether they came too late to save a butterfly that may anyway be doomed as a Dutch species.

Habitat of the Cranberry Blue

The other wetland site I needed to visit required a drive of perhaps an hour to the north-west, to the impressive Fochteloërveen, an extensive protected area on the border between Drenthe and Friesland. As well now hosting a growing breeding population of Cranes, Grus grus, this wild, open expanse is home to the Netherlands’ last viable population of the Large Heath, Coenonympha tullia, which despite its overall rarity, can be numerous in some years here.

Former peat cuttings can clearly be seen on the Fochteloerveen

Although the clouds were closing in fast, there were still a few Ringlets, Aphantopus hyperanthus, and Large Skippers, Ochlodes venatus, as well as one unexpected addition to my 2014 list, a lone Gatekeeper, Pyronia tithonus. Luckily, just before the weather closed in altogether, I was able to spot one Large Heath dancing over the long, pale brown grass, thereby bringing my 2014 list up to 66 species.

One final bonus, once the butterflies had disappeared with the sun, was a splendid showing of Broad-leaved Marsh Orchid, Dactylorhiza majalis subsp. majalis, which were growing in disturbed ground along the cycle track that crosses the fen.

A fine group of Broad-leaved Marsh Orchids

Butterfly list as of 30th June 2014: 66 species