Map sighting near Swanage

[Pete Eeles]

I've been notified of a sighting of a summer brood Map (male) near Swanage. Some details below. Genuine migrant or release?

The first report was from Steve Smith:

"Was out photographing butterflies this am with a local friend, Brian Arnold & his Londonish based mate Derek, in the Swanage area of Dorset. The long & short of it, is I found a male second generation Map Butterfly & we got some pretty reasonable photos on & off this afternoon, although it disappeared out of view for long periods. I've put my sightings together along with upper & underside photos on my blog: http://birdingpooleharbourandbeyond.blo ... e-map.html

I'm still in two minds about the vagrancy vs release option. Have favoured the latter option, based on feedback I had this afternoon, but also some very recent feedback about vagrancy sounds encouraging. Being in the Swanage area, then the area does have a good track record for Moth & Butterfly vagrancy. On the downside, there hasn't been any mass Moth migration in recent days, but we have had a big Clouded Yellow movement into Dorset in the last 10 days & I saw about 15 or so today."

Steve was with Brian Arnold at the time, who sent me this:

"I saw and photographed this butterfly at the base of a hillside near Swanage today. It is a male 2nd generation/brood MAP butterfly - also known as a European Map. The question is of course - how did it get there?

Four of us who were out photographing butterflies saw it, and Steve Smith who was with me contacted a friend who spoke to Dr Phil Stirling. He said that it is not known to be a migratory species, so the assumption has to be that is was released by someone.

Personally I find it hard to imagine that someone would release this species as it is quite small and not particularly spectacular, unless they wanted to just photograph one outside in the open. However - who knows? It will be interesting to find out if there are any more reports of the Map butterfly being seen in Dorset, or indeed elsewhere?"

Cheers,

- Pete

[langtonbirder]

Hi guys,
had this feedback from Steve Morrison overnight, an ex local Birder & Insect ecologist, who now lives in France:-

I wouldn't dismiss the record so easily as an 'escape'.
The second brood is more dispersive than the first brood and in recent decades the species has moved rapidly north and further afield elsewhere in Europe (and still is) in response to the warmer summers; this suggests a high dispersal rate. It's also becoming more common on the Continent (I get it in the garden down here in France) so all the ingredients are there for a vagrant appearing at Swanage.
There was a 1995 record in Kent (ref: The Millenium Atlas) and the record was thought to be a vagrant from France.

So unless you can find proof that is was a 'category E' then I would think vagrancy is quite likely, particularly taking into account the weather conditions this summer and the location of the record on the south coast where such records are most likely.

I would think it most likely it's tickable, but making local enquiries about the presence of butterfly breeders wouldn't do any harm.
Steve M.

Steve Smith

[MrSp0ck]

I have noticed many migrant species the last week, Clouded Yellows, Painted Ladies and Silver Y. Last Sunday i was on the undercliffs at Beachy Head, Cow Gap and Clouded Yellows and several Nymphalids eg Small Tortoiseshells were flying in from the sea. With Camberwell Beauty, Scarce Tortoiseshells, Long Tailed Blues etc this year, a migrant map cannot be ruled out, giving the coastal location and the base of a hillside/cliff.

[Neil Hulme]

Hi all,

It is wrong to discount this as a genuine vagrant on the basis that the Map is not a migratory species. Many non-migratory species have been found on e.g. lightships over the years and we undoubtedly underestimate (or don't even acknowledge) occasional Channel-hopping by the most unlikely of species, some of which are considered sedentary. I've seen Brimstone doing it!

The triggers for, mechanisms and patterns of butterfly migration are different to those of butterfly dispersal (both self-powered and weather-forced), but of course the results are potentially the same. Look at the invasion of Sweden by the non-migratory Purple Emperor - it is quite clear that a significant expansion of geographical range can be achieved by dispersal (a mechanism usually resulting in more modest movements), rather than necessitating habitual, longer distance, migratory behaviour. Many species have been extending their ranges northwards for decades within the UK, now reaching Scotland. If a relatively narrow strip of water had been placed through the middle of the UK I bet that a few species, such as the Comma, would have already made it across and still been in Scotland afore ye.

At the moment I don't see any evidence for this being a release, although that might of course change.

BWs, Neil

[Pete Eeles]

An update from Brian Arnold: "We have now seen 4 individuals - all quite fresh looking - one female and 3 male".

Cheers,

- Pete

[jasonbirder]

Any location details?
Is anyone going to try for this tomorrow?

[langtonbirder]

Hi Guys,
quick update. Now raining but I think we have seen 7 individuals today - 5 males & 2 females. Apart from one tatty male, the others all look pristine condition. But this is provisional & Will need to wade through photos to be sure of exact numbers.

As for releasing the site, we still have big concerns about the impact of a collector on these Butterflies, regardless of their origin. So need to discuss this further before a decision regarding letting the site out. Currently its been raining for well over an hour & its game over for today.

[Essex Bertie]

Not quite in the same league, but for the past 2 years, we've had Chalkhill Blues in Essex - just a few singletons on the high ground along the northern edge of the Thames flood plain. So these have travelled tens of kilometres from Kent, over the Thames.
Whilst on a boat in the Blackwater Estuary (Essex), I've seen a couple of Ringlets happily bobbling across about 8' above water level. I worked it out with wind direction that they were about 1km into a minimum 2km crossing. Also nearby on Osea Island have seen a Meadow Brown happily drift off the low cliff edge, off towards the mainland.
We've had vagrant Grayling (no longer extant in Essex) undoubtedly come in off the North Sea onto the Essex Coast. Probably happens with a lot of species, not just the known migratories.

[Jack Harrison]

Why shouldn't these Maps be genuine immigrants? Colonization has long been predicted.

Jack

[dave brown]

As for releasing the site, we still have big concerns about the impact of a collector on these Butterflies, regardless of their origin

Whilst I would like the opportunity to visit the site and view the butterflies, I can understand the reluctance to release precise location details. Whilst many people enjoyed the Long Tailed Blues here in Kent last year its now obvious that someone did collect. Luckily the numbers of butterflies being seen at various sites was able to withstand some loses. With only 7 individuals available this is going to be a tough call for the finders.

[jasonbirder]

I guess the easy answer in future is to agressively challenge anyone with a net...
I confess I saw two people with nets at Daneway Banks in June and while I questioned them I meekly swallowed their story of collecting Small Eggar (or similar) Caterpillars...
With Hindsight I should have chased them off...but as a new Butterflyer I didn't really understand the etiquette for that sort of situation...
I only hope my oversight doesn't impact on the success of Large Blues at this beautiful site next year...

[Neil Freeman]

Given that a number of individuals have now been seen, could it be that these are the offspring of a vagrant female that arrived undetected earlier in the season ?

Cheers,

Neil.

[Paul Harfield]

It is great to see the Map on UK soil. Hopefully the colony will survive. Whether this be a natural invasion or a deliberate realease, surely it was almost a certainty that this species would arrive on our shores at some point. I reared this species many years ago as a child and remember it as a delightful little butterfly. I have some questions for the experts.

Assuming this group of Map butterflies is descended from a single female, could a colony establish itself without further input from fresh blood? Or is a colony destined to fail without input from several bloodlines.

At what point does a non-native species become a native species? what are the official criterion for a reclassification?

[David M]

I guess the easy answer in future is to agressively challenge anyone with a net...

Agreed.

At all times I personally reserve the right to confiscate nets if I feel such action is necessary. Butterfly collectors in the UK are an anachronism in 2014 and they should be made to feel intimidated and unwelcome wherever they ply their trade.

I'm content to accept scientific reasons for capturing butterflies on those rare occasions where it is appropriate, but if I don't feel convinced by those reasons then I'm perfectly happy to attach myself like a limpet to those carrying nets in order to make them feel as uncomfortable as possible (and take action if need be).

[Padfield]

Assuming this group of Map butterflies is descended from a single female, could a colony establish itself without further input from fresh blood? Or is a colony destined to fail without input from several bloodlines.

I'm not answering as an expert, but I believe a colony descended from a single female is possible. There will doubtless be greater loss from lethal homozygous combinations - most likely resulting in failed eggs - but I would be surprised if this proved to be the limiting factor in the survival of a population. Cheetahs (I'm told) have twice in their history been reduced to just seven individuals - and thrive. With the much higher fecundity of butterflies you would expect greater resilience - after all, genetic failures don't feed the predators and parasites.

Guy

[Pete Eeles]

I guess the easy answer in future is to agressively challenge anyone with a net...

Agreed.

I personally wouldn't assume that someone with a net is up to no good, and politely ask them (out of a genuine interest) what they're studying. The last time I asked someone was on Martin Down, who was a scientist looking at bees. And the first time was in Pamber Forest when the chap with the net turned out to be Graham Dennis - the warden (monitoring Orange underwing moths)! So it's not always for negative reasons.

Cheers,

- Pete

[David M]

I guess the easy answer in future is to agressively challenge anyone with a net...

Agreed.

I personally wouldn't assume that someone with a net is up to no good, and politely ask them (out of a genuine interest) what they're studying. The last time I asked someone was on Martin Down, who was a scientist looking at bees. And the first time was in Pamber Forest when the chap with the net turned out to be Graham Dennis - the warden (monitoring Orange underwing moths)! So it's not always for negative reasons.

Cheers,

- Pete

Agree entirely, Pete.

Last year, I politely challenged an individual on Crymlyn Burrows and he explained that he was capturing bees/wasps/hoverflies for scientific reasons. I was perfectly happy with that explanation because he was close to the shoreline where butterflies are scarce, but if I bump into someone later this month at the Brown Hairstreak site in Pembroke with a net, then my line of questioning will be far more direct, believe me.

[essexbuzzard]

The fact is,there is nothing wrong with people carrying nets-i often do so when travelling to Europe,except in areas where it is not allowed. Very few species are legally protected,so no-one has any right to tell anyone else not to net butterflies,except on private land. Although i deplore those that take butterflies home for their own purposes,of course.

We are supposed to be a friendly bunch,and it does nobody any good to accuse everyone carrying a net of being up to no good. Imagine if you were just starting out on butterflies and someone came up to you and started off? You would probably never go near a butterfly again! How does that help the future of conservation?

[HarassedDad]

Oh dear. the divide between entomologists who are into butterflies and birdwatchers who are into butterflies rears it's head again.

As someone who always has a net with me, let me put the case for the defence.

1 Insect nets are used for all flying insects, not just butterflies. Correct identification of most groups requires close examination under a hand lens. Sometimes it even requires killing the insect, even in some cases lepidoptera.

2 Insects are not birds: what makes an insect rare or endangered is not that there aren't very many of them, it's that they are restricted to a few sites. Within those sites they can be quite abundent. With rare birds the loss of a clutch or an individual of breeding age has a significant impact on the population. With most insects laying several hundred eggs - the majority of which will never make it to adulthood - the loss of one or two individuals has no effect on the population.Far more Black Hairstreaks are killed legally every year by farmer's flailing hedges than were killed by every butterfly collector in the history of the world, and they aren't extinct yet.

3 Butterfly collecting is actually not illegal in this country - although it is illegal to collect certain species without a licence, and illegal to collect any species at certain locations without a licence. But at the the moment, as the law stands, it would be perfectly legal for me to lean over your hedge and catch a Peacock off the buddliea in your garden (as long as I didn't damage the buddleia), and kill it and pin it, and even then sell it on ebay, and you would have no recourse legally except to take out an injunction to stop me doing it again. We might wish the law was different, but that's the law as it stands.

4 "Confiscating" a net would be a criminal act of theft leading anyone who did it to certainly face charges, irrespective of whether the net belonged to someone who was illegally collecting. The police would certainly see the loss of property as more significant than an offence against the wildlife and countryside act. If you suspect someone of illegally collecting, ring the wildlife protection officer of your local force (nearly all counties have them and their number should be on your mobile before you need it) and make a note of any numberplates in the car park. Don't be tempted into vigilantiasm. Having said that, if you are on a nature reserve or SSSI it's perfectly in order to ask if they have a licence to collect: genuinely licenced individuals would be happy to show it. However, you don't need a licence to catch insects for id, only to kill them. The give away would be the collecting satchel, not the net. An individual who only has a net isn't collecting. To do that you need a bag with killing fluid, envelopes or tubes for the catch and a host of other paraphernalia.

This paranoia about insect nets is near universal - which makes it amusing when I lead walks for the local branch of Butterfly Conservation, net in hand.

Andy B
Norfolk County Butterfly Recorder

[David M]

The fact is,there is nothing wrong with people carrying nets

I'm prone to agree, but when people are carrying nets on sensitive butterfly sites, then one simply has to be suspicious by default.