A European Swallowtail, photographed in Poole on 15/08/2015 – let us know if you spot one!
[Update to the article below: as of 5 July we have had six separate reports of Continental Swallowtails in Purbeck, all around the St Alban’s Head area. There seem to be certainly two and probably three individual butterflies. The Continental Swallowtail is different to our native species, which is now only found breeding in Norfolk, where habitat is managed to provide the foodplant needed by its caterpillar, which is Milk Parsley.]
We had several reports of Swallowtail butterflies in Dorset last year, including one of caterpillars on carrot leaves in a garden in Wimborne, suggesting they might be breeding. You might also have seen on Springwatch that the Continental Swallowtail definitely bred in Sussex last year.
We have been waiting to see what would happen this year, and two separate reports of Swallowtails have just come in from St Alban’s Head (also called St Aldhelm’s) in Purbeck. On 28th June a group running orienteering relays saw one pitched on the path and on 29th June a watchkeeper for the National Coastwatch Institution at St Alban’s Head saw two circling around; she had recently seen them in Switzerland and was very confident of the identification.
We do not know if these are migrants, have bred locally or are releases, deliberate or accidental, but we would like to know of any other sightings, with a photo if possible. Please send your sighting to [email protected]
The sightings just keep on coming!
- 6th July – Peter Poore reports – and photographs – a Swallowtail laying eggs on his carrots: you can see the photos on our Gallery page.
- 12 July – Swallowtail sighted in a Bournemouth garden, on Choisya Aztec Pearl shrub.
- 23 July – Swallowtail caterpillars reported on fennel in a garden, in Furzehill near Wimborne. Photo below.
A few days later the caterpillars had disappeared; our Records Officer, Bill Shreeves, says:
The caterpillars may have progressed into the chrysalis stage – they look fairly mature from the photo. Predation is another possibility: despite having chemicals in their bodies which are distasteful, they can be predated by birds, especially in areas where the species is not well known to local birds. Caterpillars feed for about a month before pupating so it is just possible that these may have offspring of the butterflies seen in the Pamphill area in late May. The continental sub species feeds on a whole range of umbellifers, fennel & wild Carrot. Back in the 1940s, when there was thought to have been a Dorset breeding colony for 2-3 years, caterpillars were found on Wild Carrot. The native Swallowtail of course uses almost exclusively Milk Parsley but I doubt whether any of the recent sightings have anything to do with this.
Another Swallowtail has been sighted – on 12 July, in Bournemouth. This adds to earlier sightings:
- 7 June – Hengistbury Head, Bournemouth
- 2 June – Durlston Country Park, near Swanage
- 2 June – Pamphill near Wimborne
- 31 May – Pamphill near Wimborne
The recorder of the most recent one got a photo, and it shows some damage to one of the wings, so it can be recognised if it is spotted again.
Another Swallowtail has been sighted, on 2 June, by eagle-eyed 8-year old Jess Nicholls, at Tilly Whim Caves, Durlston Country Park. Luckily Mum, Nicky, was able to get a photo on her phone – see below. Very big thanks to Jess and Nicky for getting the information to us.
Jess’ Grandad, Malcolm, sent us some further detail:
The weather at the time (c10.30hrs) was warm, approx 18C, with just a light NW breeze. The butterfly was first spotted by Jess at the entrance to Tilly Whim Caves. The Caves are approx 20m above sea level in an area of steep limestone cliffs with abundant thrift currently in full flower. The butterfly circled around this particularly warm and sheltered area for 20 seconds or so allowing all three of us to have good views before it moved a few yards to the west where it settled on some thrift adjacent to the coast path. It remained in this position for some 10 to 15 seconds allowing my daughter Nicky to take photographs on her iphone – I must say that I was rather surprised that it stayed in one place for so long and also that it allowed her to get so close. The Swallowtail then headed off to the west.
A Swallowtail has been reported on Pamphill Moor (ST995006) – seen on 31 May from 12.00-12.15pm. As our native Swallowtail (papilio machaon britannicus) has been shown by research to never ‘migrate’ out of Norfolk, this has to be either a continental Swallowtail (papilio machaon gorganus) or a butterfly released by someone who has bred it. We know there has been a huge influx of migrant birds around 30-31 May, so a continental migrant is not impossible. To know which species it is, we need photos, so if you are in the Wimborne area and see it, please take some shots and send them to us: [email protected]
The only native Swallowtails in the UK are in Norfolk, where their habitat is very actively maintained for them by humans. Their caterpillars feed on milk parsley, which is not present in Dorset, so if some artificially reared specimens have been released, they will not be able to complete their life-cycle by breeding.