Strange blue sighting on Lardon Chase. Berks.

[nomad]

Today, I visited Lardon Chase above Streatley in West Berkshire to photograph the Chalkhill Blues, there were also a few Common Blues about. After lunch in the Pub-the Bull Inn below, we then returned and low down on the hill, I followed a strange looking blue. I only had time to take a few shots and it then disappeared in the bright sunshine. A great pity I did not see the underside, I think is probably a Plebejus argus-Silver-studded Blue male, although it seemed a little larger. A very strange sighting for a chalk hill above the Thames and where the nearest P. argus colonies are many miles distant. The only other blue that comes to mind is the extinct and very rare vagrant, the Mazarine Blue. It's all quite strange indeed. I would appreciate your comments. Peter

Chalkhill Blue male

Common Blue Male

Silver-studded Blue?

[David M]

That last one's SSB all over!!

[nomad]

I thought so, Thank-you. Any idea why I should have found a Silver-studded blue on a chalk hill above the Thames.

Peter.

[David M]

I thought so, Thank-you. Any idea why I should have found a Silver-studded blue on a chalk hill above the Thames.

Peter.

There must be a colony within reasonable striking distance as this species is notorious for being reluctant to populate new sites.

Interestingly, there has recently been a SSB sighting on Bindon Hill, near Lulworth Cove too, although there are populations not terribly far from this location.

[nomad]

Thank you David, yes it is also strange that they turned up on the chalk of Bindon Hill this year. Lardon Chase and Lough Down are just fragments of unimproved downland with miles of cultivated land all around. I have to check, but I believe the nearest Berks heathland colonies are much to far for this little butterfly to have traveled from. I never heard of it from this locality before. It was such a surprise.

[Charles Nicol]

a great find nomad !! hopefully Guy & the other experts will give their opinion in due course...

[nomad]

Thanks Charles. The only other possibility that I can think off, is someone has released some Silver-studded blues on this hill, but this does seem very improbable. If they came from a heathland site then they probably would not be able to breed here. Also the chances of someone finding them again would be very small. The male I photographed is not pristine, but it does not look that worn. Peter.

[Pete Eeles]

The nearest colony for SSB I know of is Silchester Common, which is around 14 miles as the crow flies which is quite a distance!

Cheers,

- Pete

[nomad]

Thanks Pete. I have been to Silchester common a couple of years ago and did not find the Silver-studded Blue really plentiful there. One recorder on the Oxon-Berks sightings page visited Silchester recently and the few Silver-studded Blues seen were rather worn. I would be surprised if this male has flown such a distance across the Berks downs to find its way here. I only found the one in the photograph. I was mostly higher up the down earlier in the day. It's quite a mystery. Regards Peter.

[David M]

It's quite a mystery.

It IS something of a mystery, but a very positive one, it has to be said.

It's nice to see any species turn up at a site unexpectedly. It's better still when a relatively 'static' one does so. Let's hope for more in the future.

[nomad]

I once saw a male Purple emperor flying at high speed across the Marlborough downs, miles away from the nearest colony in Savernake Forest. A strange sighting, but the rather sendentary Silver-studded Blue on the chalk at Lardon Chase was even more of a butterfly surprise. I have sent the record to the Oxon - Berks- Bucks butterfly recorded. Peter.

[Jack Harrison]

nomad says

I once saw a male Purple emperor flying at high speed across the Marlborough downs, miles away from the nearest colony in Savernake Forest.

Mike Rubin had a close encounter with a Purple Emperor on Dunstable Downs in 2012. Link record shot: http://www.flybywire.org.uk/pictures/ga ... G_2015.jpg

Jack

[Neil Hulme]

Hi all,

Some species are beginning to behave a little differently in the UK, probably as a result of climate change, allowing for a broader range of habitat associations. Their behaviour thus begins to more closely mimic that of their kin further south within their global distribution range. Silver-spotted Skipper is a well-documented example.

Purple Emperor has always been comfortable at altitude in mainland Europe, but historically has been associated with lowland, mixed woodland in the UK. Since the later part of the C20th it has started to appear all along the crest of the South Downs, up to 238 m (780') amsl. These are not just hill-topping males; they breed up here. I now regularly see them battling high above the very crest of the Downs, and swooping across open downland pasture and arable landscapes. I've personally seen them on the Downs at Cocking, Heyshott, Graffham, Bury and Storrington. They are now breeding on Blackdown, the highest point in Sussex. Others are now reporting them at altitude in other parts of Sussex. All they need are a few suitable breeding sallows, which can be strung out over quite a distance. They don't need oak either. Further changes in butterfly behaviour are inevitable.

BWs, Neil

[Jack Harrison]

Those SS Blues at Lulworth and Lardon Chase.

Are they definitely ssp. argus (the heathland form) or do they show characteristics of the (presumed extinct) downland ssp. cretaceus (as apparently do those found in the Portland quarries)?

Jack

[Neil Freeman]

The SSBs that I saw on Bindon Hill are in a report with photos in my PD along with reports and photos of SSBs from Portland and Tadnoll Heath

viewtopic.php?f=29&t=5424&start=1060

There were at least 3 individual males on Bindon Hill in varying condition plus a possible female that I lost sight of before I could be sure. I am not familiar enough with this species to be able to comment on their characteristics other than they did seem possibly slightly larger than those I have seen previously at Prees Heath.

Cheers,

Neil

[nomad]

What was strange about the Purple emperor that I observed was than it was flying at speed and came close to me in very open cultivated downland, where there is no woodland present for many miles. I think the Silver-studded blue male that I found on Lardon Chase looks similar to those that I have observed on heathland. As for cretaceus that used to occur on the North and South Downs, I think we have to accept that like masseyi, it is another sad loss for the U.K. Peter.

[nomad]

Well- I sent this record and a photo to the three counties recorder, but I have had no feedback or even a mention on their website of a notable new record.

[Grahame]

Hi Peter

A remarkable sighting! Very hard to explain.

Whilst there are a ',number of European species that look very similar to the SSb, I agree that this looks like a SSb and not a Mazarine blue.
With the apparent demise of the SSb from decoy Heath all of the recent Berkshire records of the SSb have come from the Crowthorne ares, with the nearest colony to Lardon Chase being Silchester Common just over the Hampshire border.
All of the literature suggests that this butterfly is highly sedentary. Most of this research was done on edge of the range colonies and may not represent the true nature of the species further south. However this sighting is a very long way from the nearest known colony and an adventurous male seems unlikely, especially as numbers locally have been poor and the weather less than ideal.
It is interesting that you say this specimen seems larger than normal as the calcareous race cretaceae was indeed larger. For this race to have survived on Lardon Chase unrecorded whilst the recess of the race went extinct seems very unlikely. It is remotely possible that someone could have released some specimens from the Portland colonies but they would have had to pass a lot of more similar habitat to do so.
If they had taken specimens from a heathland colony for an introduction, sites such as Greenham, Crookham, Snelsmore or Bucklebury would have been more obvious recipient sites.
Could an individual have hitched a lift in someone's car? Possible but highly unlikely. This species is available from breeders.

In conclusion, a real mystery and a great spot.

Sorry I didn't respond sooner but this evening was the first time that I saw your report as I think you have probably sent your email to my work account which I will not see until tomorrow.

Best wishes

Grahame

[MikeOxon]

Could an individual have hitched a lift in someone's car? Possible but highly unlikely.

I had wondered about this, too. After all, 'butterfliers' do tend to drive from one site to another, so it is not inconceivable that someone could have parked at Silchester (say) and then unwittingly transported a butterfly to Lough Down. It's certainly unlikely but not impossible, I suggest.

I recall an incident several years ago, when looking for Black Hairstreaks in Waterperry Wood. I had parked in a small lay-by, tucked in close to a hedge. I'd had no luck with the BH but, when I returned to the car, there was one in the hedge, immediately by the car window! I took photos from the car and it could easily have accidentally flown inside (though it didn't).

Mike

[Pauline]

Fairly recently I arrived at OWH and realised I had a Meadow Brown in the car. How long it had been there and where it had come from I have no idea. It took a while to get it out but it ended up on brambles at a completely different site. I have also had a Large Skipper fly into my car this year as I sat in a traffic jam with the windows open.