Orange butterfly with black markings perched on a branch

Large Tortoiseshell. Photo: Adrian Riley

Family: Vanessids
Size: Large   Wingspan: 67mm

Once widespread across Britain, the Large Tortoiseshell became extinct by the 1960s. A new colony seems to have formed on Portland, probably from butterflies released by humans rather than naturally arriving. Found in Europe, but declining in numbers.

Not known as a resident UK butterfly for many years, but there have been sightings along the south coast, and we have had them recorded in Dorset for several years in a row, suggesting there is a colony being established. We will not count it as a ‘Dorset butterfly’ until at least five years of sightings are recorded.

The following figures are of sightings reported to the Dorset Branch of Butterfly Conservation, mainly via this website:

  • 2018 – 5 sightings
  • 2019 – 5 sightings
  • 2020 – 39 sightings
  • 2021 – 24 sightings

Where to see

  • Habitat: Woodland edges and wooded lanes.
  • Caterpillar foodplants: Prefers Elm, though has also been found on willows, Poplar and other trees.
  • Best places: Only being seen regularly on Portland, often around Church Ope.

Distribution map

Large Tortoiseshell was recorded from these 1km squares in Dorset (2015-19).

  •     1 record
  •     2-9 records
  •     10+ records

When to see

The best month seems to be July, but sightings have come in for January, February, March, April, June and August.

Sightings by month (last 5 years)*

Compare flight times for all species.

This year and last*

Browse the sightings archive.

What to look for

The other butterfly with which you are most likely to confuse this butterfly is the Small Tortoiseshell; at a glimpse you may also think it is a Comma, but it does not have the Comma’s jagged edges to its wings.

The Large Tortoiseshell is a generally duller butterfly than the Small, looking more orange than red-orange and with less black on the rear wings.

The Small has a very white/silver mark near the tip of the forewing which is lacking in the Large.

You may be able to make out that the Large has four dark marks on the upper forewing, as opposed to the three of the Small and the blue marks around the wing edges tend to be more prominent in the Small.

The Large is a slightly bigger butterfly: 64-70mm wingspan, as opposed to 50-56mm.

The adult butterfly may be found feeding on Sallow flowers in spring, but it is an easily disturbed butterly, so your sighting may be of short duration!

Overwinter stage: Caterpillar

Photo gallery

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Find more Large Tortoiseshell related content, including news and photos.
*Note: The charts shown on this page are drawn only from casual sightings submitted to this website. Records from this website will be added to a lot more data collected throughout the year and used to compile the five-yearly Butterfly Atlases for Dorset and the UK.