The Continental Swallowtail Butterfly ssp. gorganus

in Dorset and south British coast. Identifying individuals.

MG: Please excuse my ignorance. I thought there was one place you could see the beautiful Swallowtail Butterfly in Britain. Somewhere on the Norfolk Broads, associated with Milk Parsley plants. There. That’s the end of my knowledge on the British Swallowtail. Indeed I didn’t even know it was especially ‘British’. Well it is. Thanks to Steve Smith who got in touch I have learnt much more. The Norfolk Swallowtails really are British- the indigenous British subspecies Papilio machaon britannicus limited to… you guessed it, the Norfolk Broads. Lots more on the excellent UK Butterflies site.

However there is a continental form Papilio machaon gorganus which rarely crosses the channel into southern England. Last summer (2013) was an exceptional year with gorganus Swallowtails reported in Hampshire, Sussex, Kent and Bucks. And it seems they did the quite unexpected, breeding and overwintering successfully and appearing this summer.

In addition adults on the wing were discovered earlier this month in Dorset. Steve tells the full story on his blog, so with these photos to whet the appetite please visit Steve’s site. Read about his discoveries and how he is exploring to see if individual butterflies can be specifically identified by their discrete wing markings.

all photos below by Steve Smith. Read all about the gorganus Swallowtails in Dorset:

               post on the discovery                     post on further explorations

worn swallow


swallowtail one

Swallowtail B: Left forewing (2 July 14) – Yellow patch A is almost square (Swallowtail A – it a longer & flattened oval) & black band C has 3 distinct triangular edges on left hand side (Swallowtail A – it’s smooth)

swall tail



One thought on “The Continental Swallowtail Butterfly ssp. gorganus

  1. Jon Dunn

    Fascinating stuff, thanks for highlighting this Martin. I remember seeing gorganus back in the 1980s in Somerset – 1984, from memory. The subspecies has, contrary to a lot of recent media reports, not bred in Britain for the first time in 2013; it was fairly well-documented by the great Dorset entomologist W.P.Curtis when it bred for a few years in Dorset in the early 20th Century. I’ve the manuscript of his (unpublished) work on Dorset Lepidoptera somewhere at home…


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