Clouded Yellow (Colias croceus) in Ireland

No standard Gaeilge name is recorded in An Coimisinéir Teanga terminology or Ó Dónaill’s dictionary. The Clouded Yellow, Colias croceus, is a migrant that reaches Ireland from continental Europe in variable numbers, in some years abundant and in others almost absent.

Identify it in four steps

1. Upperside deep orange-yellow with a broad black border on both wings; the border is patterned with pale spots in females and unbroken in males.
2. Almost never rests with wings open in Ireland; identification usually made in flight or on the closed underside.
3. Underside forewing yellow with a small dark spot; underside hindwing greenish-yellow with a small silver spot in a russet ring, a diagnostic mark.
4. Wingspan 52 to 62 mm; flight is a fast, direct, low glide across meadow and coastal grassland.

Habitat in Ireland

The Clouded Yellow is a migrant that breeds locally in Ireland in favourable years but does not overwinter. Arrivals cross from continental Europe on southerly winds between May and October, with strongest records in July and August. Larvae feed on Bird’s-foot Trefoil (Lotus corniculatus), White Clover (Trifolium repens), and Red Clover (Trifolium pratense).

Numbers vary enormously year on year. A large influx can produce a summer breeding brood that emerges in early autumn; a poor year may see fewer than a dozen national records. Coastal counties along the south and west receive the first arrivals.

Where to see it

• the south Wexford coast: cliff-top grassland and coastal clover fields receive the earliest Irish arrivals in most years.
• Old Head of Kinsale, County Cork: coastal grassland and headland verges hold summer breeders in influx years.
• the Burren coast, County Clare: limestone grassland with clover and Bird’s-foot Trefoil supports autumn breeders.

Related species

• Brimstone (Gonepteryx rhamni)
• Small White (Pieris rapae)
• Painted Lady (Vanessa cardui)