Northern Ireland's Priority Species

Orthonama vittata – oblique carpet

Orthonama vittata

Orthonama vittata (Borkhausen, 1794)
Family: Geometridae

A tiny butterfly-like moth with a distinctive, dark streak running at an angle from the tips of the straw coloured forewings. A wetland species that is on the wing from May to September. It is a Northern Ireland Priority Species because of major declines detected elsewhere in the UK. At present such data does not exist for Northern Ireland.

In brief

  • This is a relatively common moth of damp woodland, bogs and fens
  • It has two generations on the wing May to September and occurs most commonly across the southern half of Northern Ireland
  • Frequently found flying at dusk, it is also attracted to light
  • Is a Northern Ireland Priority Species because of declines detected in other parts of the UK where it has undergone a 72% decline over a 25 year period. There is no evidence as yet that the species has exhibited a similar decline in Northern Ireland but as we are part of the UK it has been included on the Priority List

Species description
A member of the Geometridae it can be described as a member of this “butterfly-like” group of moths. It rests with the straw coloured, forewings open revealing a short dark diagonal streak at the tip. There is a small discal spot and narrow dark crosslines and banding apparent on the forewings wings. There is also a small discal spot visible on the plainer hindwing.

Life cycle
There are two generations giving a flight period from mid-May to the end of September. They overwinter as caterpillars which can be found feeding on various bedstraws during June and July and in September.

Similar species
Should not be confused with any other moths that occur in Northern Ireland

How to see this species
Relatively easy to see at light especially in most of the marshy sites in north Armagh and south Fermanagh. Trapping will be more successful during the peak flight periods of June and late August.

Current status
Relatively common within the southern counties of Northern Ireland but less frequent in the north, possibly due to under-recording. More trapping in Londonderry, Tyrone and North Antrim may well reveal that it is equally common in these areas. The most northerly record is from Rathlin Island Co. Antrim.

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 (72% 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. General management for Biodiversity will help maintain the species.

  • Occurs on many ASSIs

Proposed objectives/actions

  • Occurs on many ASSIs
  • Increase Rothamstead Trap network to gather data on status
  • Encourage submission of records to the Moth recorder

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

Baynes, E.S.A. (1964). A revised catalogue of Irish macrolepidoptera (Butterflies and Moths). EW Classey, Hampton, Middlesex.
Porter, J. (1997). The colour identification guide to caterpillars of the British Isles. Viking, London.
Skinner, B. (2009). 3rd revised and updated edition. The colour identification guide to the moths of the British Isles. Apollo Books.
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