Holly Blue in October!

[Andrew Wood]

I'm interested in the discussion on Holly Blues (Celastrina argiolus) as
around me in Hertfordshire this year their numbers have been very low and
lower in the second than the first brood (on a transect,  well provided
with holly and ivy, which I walk   4 and 0  (cf 1996 when numbers were24
and 62.   Last year in Hertfordshire was an excellent year and indeed I saw
an individual on 19 October 1996, suggesting a third brood.  Yet they were
common in Cornwall when I was there in July.

I am intrigued by the geographical difference that seems to exist in the
populations of what I have always thought of as an evenly distributed but
cyclical species. Can anyone comment on this, or have I just been unlucky?

Andrew

Andrew Wood
Bengeo
Herts
UK