Wednesday, 28 October 2015

If I were a betting man ...

Long-tailed Blue (Lampides boeticus)




Further to the freshly emerged female, discovered at Beeding Cement Works on Friday, 23rd October, a male joined the party on Sunday, 25th - the female still present - much to the pleasure of the gathered crowd. A short distance away, two females, including a rather nice aberrant specimen (pictured above) showing a boldly marked post-median fascia and a strong reduction in the violet colouration typically found around the tonal black spots, were discovered by Neil Hulme near Lancing Railway Station.

Despite the overcast and windy conditions, Monday, 26th produced a freshly emerged male at Newhaven Tidemills. It was still present on the morning of the 27th until the weather warmed and it was lost to the small group of observers - small butterflies and the wind really not making a good combination!

Tuesday, 27th found me heading back to Brighton Racecourse. Having found 82 boeticus ova at this site back in September, I have been keeping a very close eye on this location - and especially as Neil discovered late October specimens during the 2013 season. Due to the constant easterly breeze - how many times have we complained about the wind this year - I found myself heading towards the leeward side of the allotments and it was here that I bumped into a local birder. After the usual pleasantries were exchanged he informed me that he had seen what he believed to be a Long-tailed Blue along the side of the gravel road which runs approximately north-south to the west of the allotments. This area is fortunately sheltered from the wind. The ambient temperature was very pleasant at around 18°C. It wasn’t long before I found a pristine male (pictured above) and probable female within close proximity. Neil and I both believe that the sheltered allotments, rich in leguminous produce, are likely to be playing an equally important role, alongside the open grassland where feral pea plants grow, in attracting boeticus to this area.

So will they appear in November?

I'm not a betting man but watch this space …

More at:

Saturday, 24 October 2015

Emergence …

Long-tailed Blue (Lampides boeticus)



Saturday, 19th September saw the first of the 2015, Sussex born Long-tailed Blues’ emerge, with two females, found by Neil Hulme at Newhaven Tidemills. Following a lengthy break in proceedings, a pristine male was discovered at Beeding Cement Works, also by Neil, on Thursday, 8th October. Despite a rather slow start things still looked promising, as in 2013, for a mid-late October emergence.

However, by Monday, 12th October the weather began to cool and, with the ever-pending threat of overnight frosts, a cold northeasterly wind set in - though the weather remained generally dry and bright. High pressure was predicted to remain over the UK for at least ten days. Thursday, 15th October was cold and overcast with a daytime coastal high of around 12-13°C; the chilly northeasterly breeze still present. On a positive note, the frosts have stayed distant, at least to date, with overnight temperatures, on average, only dropping to around 7-8°C. Although wind chill is unlikely to stop emergence it would mean a lengthened development period and also less active adults when they finally emerged, consequently they would be much harder to locate. The presence of a hard frost would be a completely different matter!

Complete development of L. boeticus (egg to adult) can vary considerably with those individuals breeding in warmer climates being substantially quicker - as short as 28 days (Cribb, 2001) - compared with those in the cooler northern hemisphere - up to 58 days and possibly longer (D. Harris, 2015, pers. comms., 19 October; pers. obs., 2015); confirmed by a female, witnessed in the wild state, having emerged on Monday, 19th October after 22 days in the pupal stage and, with an estimated egg-laying date, some eight weeks earlier, of Saturday, 22nd August. Latitude, temperature, humidity and the nature of the seasons all undoubtedly play an important role in the development of L. boeticus. This is by no means unexpected nor is it exclusive to boeticus. For example, it is believed that some slow-developing larvae of the Mountain Ringlet (Erebia epiphron) may spend two years in the larval stage, usually the result of a late spring and a short summer period.

Weatherwise, Tuesday, 20th October was the day we all been waiting for - blue sky, sunshine, highs of 15°C and, finally, the cold northeasterly wind had abated. However, this only lasted for a day as Wednesday, 21st was wet and windy. Despite dull and overcast conditions, a freshly emerged female (pictured above) was discovered at Beeding Cement Works on Friday, 23rd October. I feel sure that the 2015 season is far from over and that we may still see fresh Sussex born boeticus in November …

More at:

Cribb, P. W. (2001). Breeding the British Butterflies. Edition 3. Orpington, Kent: The Amateur Entomologists' Society, 18, pp.49-50.


Monday, 12 October 2015

Northern Wheatear ...

Northern Wheatear (Oenanthe oenanthe)

Autumn passage ...



With its flash of white rump, the Northern Wheatear O. oenanthe is a rather smart, insectivorous passerine.

It has a vast range across most of Europe, the Palearctic and as far as Greenland and parts of Arctic North America. Astonishingly, as their ancestors before, all migrate to winter in Africa in a belt south of the Sahara - one of the lengthiest recorded migrations of any small bird. The British population is currently estimated (2014) at 230,000 pairs; most of which are concentrated in the uplands of the north and west. It is a very scarce summer visitor, though regular passage migrant during spring and autumn, along parts of the Sussex coast and Downs.

A bird I am always pleased to see …

References:

Yates, B.J. and James, P. 1996. Wheatear. Birds of Sussex. Sussex Ornithological Society, pp. 425-427.
Yates, B., 2014. Northern Wheatear. The Birds of Sussex. Thetford: British Trust for Ornithology (BTO) Books on behalf of the Sussex Ornithological Society, pp. 522-523.