Celastrina argiolus

Holly Blue


by Matt Rowlings

copyright © 2003-2024

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Vaud, Switzerland, January 2007

An exceptionally early male.

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Vaud, Switzerland, January 2007

An exceptionally early male.

Field notes and information

This butterfly is a familiar sight across much of Europe and north Africa. A butterfly of trees and bushes, woodland and garden alike. In northern Europe, the first blue to fly in the spring.

It is (the only?) European butterfly to show distinct preferences of food plant in some habitats according to the brood - holly (Ilex aquifolium) in the first brood and ivy (Hedera helix) in the second.

There is marked sexual dimophism, the females have very broad black borders on the upperside.

Identification & Similar species: The pale shining grey-blue with small spots on the underside is distinct to this species.

Distribution & Flight: Most of Europe and north Africa, with the exception of the northern UK and northern Scandinavia. Evidence suggests that it is spreading north in the UK, probably linked to climate change.

Flies in two or three broods. One of the first butterflies to emerge in spring it can be found in April/early June, July/August and then, in lower numbers, September/October. Amazingly I found a perfect male on 20th January 2007 in Switzerland following exceptionally warm December and January. I don't think he would have had much chance of finding a mate so far out of season.

Habitat & Behaviour: Diverse, wherever trees and bushes grow. Larvae feed on a very wide range of shrubs. As noted above, in some situations there is a distinct seasonal preference in the selection of food plant.

Often seen flying high around bushes and trees, which is uncommon in almost all other species of blue in Europe. It rarely opens its wings when at rest, being slightly more likely to do so in cooler conditions.

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Rhodes, Greece, May 2017

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Valais, Switzerland, May 2022

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Valais, Switzerland, May 2011

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Rhodes, Greece, May 2017

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Corsica, France, July 2012

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Vaud, Switzerland, July 2012


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Valais, Switzerland, April 2004

A male taking salts from dung.

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Vaud, Switzerland, April 2010

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NW Greece, July 2016

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Valais, Switzerland, March 2020

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Geneva, Switzerland, April 2021

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Valais, Switzerland, July 2021

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Vaud, Switzerland, April 2020

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Valais, Switzerland, April 2012

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Piedmont, Italy, June 2011


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Valais, Switzerland, August 2006

Female, characterised by the extensive black markings on the upperside.