Thursday, July 14, 2011

Savernake Subsides...

Savernake Forest, Wiltshire, has now added its illustrious name to the lengthening list of places experiencing a dire iris season (in terms of adult numbers). The butterfly seems to have emerged in desperately low numbers in most (but not all) districts.

Today I conducted my annual standardised count of males in ten territories along Three Oak Hills Drive in southern Savernake, in near-perfect weather and with the males at peak (Sav is a 'late' site). I struggled to record six males, compared to 14 in 2010 and 17 in 2009. The previous lowest tally from a comparable count was ten (in 2007). Today's count fully backed up impressions gained in previous visits to Sav this season - that males are decidedly scarce there.

The good news is that I witnessed a wonderful egg-laying performance from a huge and pristine Empress in a distant part of the forest, and learnt of another stunning female being seen laying eggs near The Column (a piece of 18th century bollox) and yet another fine lady being photographed down on a grassy ride nearby.

This is proving an exceptional year for Herself coming down to the ride surfaces (usually to grassy rides or the grassy edges of surfaced rides). Perhaps there's a shortage of honey dew (or whatever the females feed on) in the trees?

I'm now giving up trying to work male territories, and will concentrate on the females for the rest of the season. Males become lethargic when they are sole occupants of territories, and most territories are at best holding single males only. Also, one of the main causes of male activity is small flies landing on their basking wings, but there's a paucity of small flies high in the canopy at present (due to pulses of foul weather).

The females need to lay every egg they can this month, to restore numbers for next year. It's vital that they don't get knocked out by a gale, as happened this time last year - and guess what's forecast for this weekend...

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