27348_male_Hautes-Alpes_15Jul11

30804_male_Hautes-Alpes_7Jul12

41598_male_Hautes-Alpes_15Jul16

41599_male_Hautes-Alpes_15Jul16

41617_male_Hautes-Alpes_15Jul16

41608_male_Hautes-Alpes_15Jul16

27329_male_Hautes-Alpes_15Jul11

A very small and very rare Pyrgus with very few locations in France, limited to the départements of Hautes-Alpes and Alpes-de-Haute-Provence. Its range extends eastwards through Switzerland and into Austria.

The upperside is characterized by very small and separated white marks on the upf and an almost unmarked uph. However, very small individuals of the Large Grizzled Skipper (P. alveus) and the Olive Skipper (P. serratulae) can occur and both have lightly marked upf. A sight of the underside is probably necessary for confident identification of warrenensis. I have only seen relatively few individuals but was fortunate enough to see both surfaces on at least  two occasions when the underside matched T&L very closely for warrenensis and there were very good reasons why it was not serratulae and almost equally convincing reasons why it was not alveus.

Another feature, it appears, is that the forewing is rather narrow; this seems to be constant.

There are many more examples on Matt Rowling's excellent web site:  www.eurobutterflies.com/species_

pages/warrenensis.htm showing the range of markings.

It flies at very high altitudes, Lafranchis giving the range as 1700-2300, although one location where I have seen it was at 2550m. It tends to emerge rather earlier than other high altitude Pyrgus, so this may explain why 27348 and 41598 looked rather worn on 15 July (albeit in different years).

ref

sex

observations

alt. m

27348

M

a rather worn male, with white markings perhaps slightly larger than average for warrenensis. The underside is 27329.

2550

30804

M

another example, the size being evident in the field.

2550

41598

M

a rather worn but I think unmistakable male warrenensis, its small size being very apparent in the field.

2020

41599

M

a fresh male from the same location and day as 41598, showing the limited and rather characteristic markings of this species which, together with its small size make it not too difficult to identify in the field.

2020

41617

M

another shot of the same individual as 41599.

2020

41608

M

the underside of 41598, which removes any possible doubt that it could be a small alveus or serratulae.

2020

27329

M

the underside, not a great photograph and showing signs of wear but the markings are quite clear enough to confirm warrenensis. This is the underside of 27348.

2550