Small Blue

The Small Blue butterfly is the smallest species of butterfly in Ireland and also has quite a restricted range, only being found in certain areas across the country.

Can you see it? The Small Blue certainly is tiny, so even if you are in an area where it’s found you might not spot it straight away – Oisín Duffy

As mentioned above, the Small Blue is Ireland’s smallest butterfly species, with a wingspan range of only 20-30mm. Its small size is one of the key identification features as even though the other species of blue butterfly are not large, then are much bigger than the Small Blue. Unlike the name suggests, the Small Blue is not so much blue but a silvery to grey to charcoal ombre appearance (there will however be a slight blue appearance) with a distinctive white border.

The topside of the Small Blue, the blue colour is most concentrated nearest the body and grows to a deep grey, dark silver colouration, the white fringing around the wings is very noticeable in the above picture – Oisín Duffy

The underside of the species is also rather silvery in colour, ranging from a light grey to a very pale blue. Black markings are present throughout the underwing, but similarly to the Holly Blue there are no orange markings anywhere on the wing.

Blue colour is most prominent on near the body on the underside also, with the colour changing to a light grey or silver, black markings are present, but notice how there is no orange markings like the Common Blue – Oisín Duffy

The species is not common and is only found in certain areas throughout the country, mainly associated with coastal grassland, but is also found in a few inland sites and of course the Burren, Co. Clare.

Head on shot of a Small Blue, its dark colour and white fringing are once again very noticeable here, and the surrounding grains of sand and strands of vegetation give a good sense of scale – Oisín Duffy

The larval foodplant of the Small Blue is Kidney Vetch (Anthyllis vulenaria) which is a member of the pea family. This species is distinctive with multiple yellow flowering heads packed into one plant, the leaves of the plant also have a unique downy silvery appearance. This species is very easy to find in coastal locations.

Kindey Vetch (Anthyllis vulenaria) the foodplant of the Small Blue – Oisín Duffy
Small Blue on its larval foodplant Kidney Vetch – Oisín Duffy

Cheat Sheet – (TLDR Version):

Name: Small Blue (Cupido minimus)

Larval Foodplant: Kidney Vetch (Anthyllis vulneraria)

Distribution: Restricted range throughout the country, few inland sites, more often found in coastal locations and the Burren.  (This is a species you will probably have to travel to see and even then, due to its small size, could be hard to find).

When: From May to June.


If you’re interested in learning more about butterflies why not take part in the Irish Butterfly Monitoring Scheme, the national scheme for recording and monitoring butterfly species in Ireland.

If anyone out there has any questions or suggestions regarding this piece or maybe regarding future pieces, feel free to get in touch through Twitter.

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