Clouded Yellow epidemic?

[David M]

The frequent sightings of Clouded Yellows have been exciting for everyone, myself included. I made a point of reading the species page for this butterfly in Jeremy Thomas's Butterflies of Britain & Ireland and I couldn't help but pontificate on what seems possible over the next six weeks.


On page 54:

...There is often a further brood that can produce enormous numbers in September and October, although this failed to materialise in 1983 owing, probably, to unseasonably bad weather.

I then checked out the Met Office long range forecast:

UK Outlook for Tuesday 20 Aug 2013 to Thursday 29 Aug 2013:

Many parts will enjoy some sunny spells through Tuesday and Wednesday, the best of which will be across southern and eastern areas where it should turn warm at times. There will, however, be some showers, mainly in the north and west with the risk of more persistent rain and stronger winds for a time. From Thursday until Saturday, most parts will continue to see fine, dry and sunny weather with warm temperatures in places. Parts of the west and northwest may be more unsettled with rain at times, and there is also a low risk of these conditions spreading as far south as the Midlands. Thereafter, dry, warm and sunny weather may continue in the south and east, although more unsettled weather is likely to affect the north and west.

UK Outlook for Friday 30 Aug 2013 to Friday 13 Sep 2013:

A good deal of settled weather is expected to continue into the early part of this forecast period, most likely leaving many regions with spells of fine and pleasantly warm weather, especially in the south and east of the country. Thereafter no strong signals currently exist for conditions during early September. As such some spells of fine weather are likely but equally, relative to the early part of this forecast period, bouts of unsettled weather may also become more likely during early September.

http://www.metoffice.gov.uk/weather/uk/ ... ather.html

So, on the face of it, we already have large numbers of Clouded Yellows here in the UK (in the south at least). We also have a fairly optimistic forecast for warm and sunny conditions to persist until at least the middle of September.

My question is this: If conditions remain favourable and the current crop of crocea set down eggs on the copious clover/lucerne we have in this country AND the long range forecast is accurate and we remain warm until mid September at least, could we perhaps see one of these epidemics before October arrives?

[badgerbob]

Hi David,
Just seen your post and was about to add this to the August 2013 pages. I saw a Clouded Yellow today at Newhaven and approached it and realised it was egg laying. When it moved off I found the egg on birds-foot-trefoil. It seemed to lay several eggs in a very short time so you could be right!!
Bob.

[millerd]

In 2009 the biggest numbers of Clouded Yellows were seen towards the end of September and persisted into early November. At the bumper site near Beachy Head, there were definite new locally emerged butterflies on 25th September, and they were still also seen coming in off the sea. There is certainly time for another home-grown crop to appear, given the fine forecast weather, and as it is likely the same thing is happening across the water in France we could be in for a repeat of four years ago. Fingers crossed... a ban on mowing of Lucerne and clover fields between now and the end of September would help!

Dave

[selbypaul]

I also have a good feeling about this year. I've also seen those long range forecasts, so fingers crossed!

[David M]

The nearer we get, the more optimistic I'm becoming.

Sure, we have the odd appalling day to negotiate in the meantime, but temperatures are not expected to drop to butterfly-unfriendly levels at any time. What's more, the latter end of the month is looking as if it may be perfect for new generation Clouded Yellows, Long-Tailed Blues, et al....

http://www.metoffice.gov.uk/weather/uk/ ... ather.html

UK Outlook for Tuesday 24 Sep 2013 to Tuesday 8 Oct 2013:

There remain signs of a rather more settled weather type across many parts of the United Kingdom during the last week or so of September, conditions then more likely than not to be drier than average. A more settled weather type should also allow daytime temperatures to be close to or a little above the late September average and as such conditions will feel quite pleasant in sunshine. Scope then for conditions to also be quite chilly by night with a risk of frost in rural areas and an increased risk of mist and fog both overnight and during morning rush hours. Probably still quite settled at the start of October, but conditions may then start to turn more unsettled during the first week of October, particularly in the north.

I'm currently building up flexi-time at work in anticipation of what may happen in 3-4 weeks' time.

[selbypaul]

I agree David. I've got a week off at the end of September. I think a trip to the South Coast for the Clouded Yellow's and Long Tailed Blue's is definitely on the cards!

[essexbuzzard]

Really? I hope you're right,guys. It's so cold in East Anglia at the moment,any extra emergences,of any species,seems unlikely unfortunately.Temperatures expected to continue below average all week. Perhaps it's better in the west,if so,can you send some warmth this way please?

[P.J.Underwood]

Hi chaps.Here is one for you.What is it and why?It is from my Croatia collection.
P.J.U.

[Pete Eeles]

It's a female Clouded Yellow, for a whole bunch of reasons, not least because it has an orange-yellow ground colour, and not the white ground colour found in the female of hyale and alfacariensis.

Cheers,

- Pete

[P.J.Underwood]

Thanks Pete,I was just worried by the pointed wings.
P.J.U.