Northern Ireland's Priority Species

Perizoma albulata – grass rivulet

Perizoma albulata

Perizoma albulata (Denis & Schiffermüller, 1775)
Family: Geometridae

Quite small and pretty, this little moth has extensive brown or grey-brown cross-bands on pale grey or whitish forewings. Has been recorded from all Counties and is on the wing from June through to late August. It can be found in wet meadows and coastal grassland and shingle where its larval foodplant Yellow-rattle can be found. 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 scarce moth associated with wet meadows and coastal grassland
  • It has a single generation, on the wing from June to late August and occurs most commonly across the south eastern corner of Northern Ireland
  • Has been recorded flying by day especially towards dusk and is also attracted to light
  • It is a Northern Ireland Priority Species because of declines detected in other parts of the UK where it has undergone a 91% decline over a 25 year period. There is no equivalent data in Northern Ireland and as we are part of the UK it has been included on the Priority List

Species description
As a geometrid it can be described as a small member of this “butterfly-like” family of moths. It normally rests with the wings open revealing extensive brown or grey-brown cross-bands on pale grey or whitish forewings. The central cross-band is the widest.

Life cycle
The caterpillar feeds on the ripening seeds of Yellow-rattle and lives inside the seed capsules in July and August. It over-winters underground as a pupa.

Similar species
This little moth is quite distinctive and should not present any identification problems.

How to see this species
This is a scarce moth with comparatively few records. Regular light trapping or netting at dusk in July and August on some of the sites listed below, where it has previously been recorded will provide the best opportunities to see this moth. Any suitable habitat with Yellow-rattle is worth trying as the moth could well be under-recorded.

Current status
It has been found in recent years in well-recorded sites such as Oxford Island, Montiaghs Moss and the Umbra. There are several recent records from Seaforde Estate, Belvoir Park Forest and Hillsborough Forest Park. Most of the records for this moth are from County Armagh and date from the 1970’s. There is only one record from County Fermanagh at Crom in 2001.

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 (91% 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 in wet meadows and coastal grassland will help maintain the species

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