Northern Ireland's Priority Species

Arctia caja – garden tiger

Arctia caja

Arctia caja (Linnaeus, 1758)
Family: Arctiidae

The Garden Tiger is one of our most distinctive and colourful moths. The forewings are variably patterned with chocolate brown patches broken by variable amounts of white. The hindwing, which is often “flashed” when the moth is agitated, is bright orange with blue-black circular spots. It occurs throughout Northern Ireland in a wide variety of habitats where the hairy caterpillars feed on a range of herbaceous plants. The adults fly in July and August and are readily attracted to light. It has undergone an 80% decline in the UK over the last 25 years.

In brief

  • Relatively common across Northern Ireland
  • It is a Northern Ireland Priority Species because of declines detected in other parts of the UK where it has undergone a 80% decline over a 25 year period

Species description
A truly unmistakable, large, colourful moth. The broad forewings are strongly patterned with dark chocolate brown patches separated by ribbons and areas of white, no two individuals are exactly the same. The hindwings are bright orange with blue-black spots and the body is predominantly orange/red. When agitated it will often rock back and forth, flashing the hindwings, as well as exuding a yellowish liquid from ducts behind the head – all designed to put off potential predators. The caterpillars often called “woolly bears” are cloaked with thick hairs which are orange/brown below and blacker above with the longest hairs being whitish.

Life cycle
The hairy caterpillars feed on a wide variety of herbaceous plants including many garden varieties. It over-winters as a small caterpillar and eventually pupates amongst vegetation close to the ground. The adult is on the wing in July and August.

Similar species
The adult is unmistakable. The hairy caterpillars can be confused with those of other members of the Arctiinae.

How to see this species
Present in all counties and in a wide variety of habitats. It is likely to be present in large, mature gardens. Easily attracted to light but rarely flies before midnight!

Current status
Relatively common throughout Northern Ireland.

Why is this species a priority in Northern Ireland?

  • Listed as a UK Priority Species and therefore on the Northern Ireland Priority List by default
  • Rapid decline (80% over 25 years 1968-2002) assessed using Rothamstead trap data

Threats/Causes of decline
It is thought to be declining in the UK as a result of many factors, including habitat change, pollution and the use of pesticides.

Conservation of this species

Current action
In Northern Ireland there are no specific actions proposed for this species other than to continue to gather records.

Proposed objectives/actions

  • Encourage submission of records

What you can do

  • Report all moth sightings to the Moth Recorder for Northern Ireland, Andrew Crory, or use the Butterfly Conservation Northern Ireland (BCNI) sightings web page at The BCNI database is managed by CEDaR and these records will then be used to update the Butterflies and Moths of Northern Ireland website.
  • Join Butterfly Conservation. Butterflies and Moths are in serious decline — with your support Butterfly Conservation can take action to reverse this.

Further information

The Butterflies and Moths of Northern Ireland

MothsIreland Website

The state of Britain's moths - an explanation as to how declines have been calculated

Background information on the Rothamstead Trap Surveys

UK Moths Website with an up-to-date distribution map

Thompson, R. & Nelson, B. (2006). The Butterflies and Moths of Northern Ireland. NMNI, Belfast.
Waring, P. & Townsend, M. (2009). 2nd edition. Field Guide to the Moths of Great Britain and Ireland. British Wildlife.

Text written by:
Allen & Mellon