Blues

A guide to butterfly species commonly found in Dorset

Adonis Blue

Lysandra bellargus

Adonis Blue
When to see:

1st Brood: Early May to Mid July
Peak: Early to Mid June
2nd Brood: Early August to End September.
Peak: Mid August to Mid September

Habitat:

Sheep-grazed calcareous downland

Where to see:

Clubmens Down, Fontmell Down, Ballard Down, Durlston CP West, Cerne Abbas, Melbury Hill

Foodplants:

Horse-shoe Vetch (short)

Behaviour:

Patrol

Atlas: Distribution map & population trends

 

Brown Argus

Aricia agestis

Brown Argus
When to see:

1st brood: End April - Beginning July
Peak: End May
2nd brood: End July - End September
Peak: End August

Habitat:

Mainly Downland, some Woodland

Where to see:

Fontmell Down, Hod Hill, Ballard Down, Durlston CP East, Durlston CP West, Townsend Quarry, Cerne Abbas, Avon Heath CP North, Avon CP South, Badbury Rings, Stour Valley

Foodplants:

Rock Rose, Storksbill

Behaviour:

Perch/Patrol

Atlas: Distribution map & population trends

 

Chalkhill Blue

Lysandra coridon

Male (blue); Photo: Mark Pike. Female (brown); Photo: Peter Lister.

Male (blue); Photo: Mark Pike. Mating pair; Photo: Terence Cheeseman

Male underside; Photo: Mark Pike. Chalkhill and Silver-studded Blue; Photo: James Gould

Comments:

We are concerned that the Chalkhill Blue seems to be dying out in West Dorset. We would appreciate help in checking the places where it has been known to be in the past. See here for full details.

 

The male Chalkhill is probably the easiest Blue to recognise: it is one of the larger of the Blues and the male has a very distinctive chalky appearance, though the female is mainly brown.

The dark veins continue through the white fringe to the edge of the wing on both male and female, similarly to the Adonis Blue, which might be out at the same time towards the end of August, making telling the females apart rather challenging; if you can get a good look at the underwing, the Chalkhill has white rather than blue outer circles to the eyespots.

When to see:

Late June/July to end of September.
Peak: Mid July to end of August, but variable - see the annual summaries on our Archived Recording page.

Habitat:

Chalk/limestone downland

Where to see:

Clubmens Down, Fontmell Down, Portland Perrryfields Butterfly Reserve, Portland Tout, Bindon Hill

Foodplants:

Horseshoe Vetch (tall)

Behaviour:

Patrol

Atlas: Distribution map & population trends

 

Common Blue

Polyommatus icarus

Common Blue


Comments

We are concerned that the Chalkhill is dying out in West Dorset. We would be grateful for help in checking sites where it has been recorded in the past. Click here for a link to a page with full details.

When to see:

Mid May to Early July. Mid July to Mid September. End September to End October.
Peak: June and August to Mid September.

Habitat:

Downland, open rough ground

Where to see:

Cashmoor, Clubmens Down, Fontmell Down, Girdlers Coppice, Lydlinch Common, Melbury Down, Sovell Down, Ballard Down, Durlston CP East, Durlston CP West, Townsend Quarry, Cerne Abbas, Kingcombe Pound, Kingcombe Redholm, Portland Broadcroft, Portland Tout, Powerstock North, Powerstock Railway, Avon Heath CP South, Badbury Rings, Ham Common

Foodplants:

Birdsfoot Trefoil, Restharrow

Behaviour:

Perch/Patrol

Atlas: Distribution map & population trends

 

Holly Blue

Celastrina argiolus

Holly Blue
When to see:

1st Brood: End March to Early June.2nd Brood: July to Mid September

Habitat:

Lanes, rides, anywhere

Where to see:

Cashmoor, Clubmens Down, Piddles Wood, Ballard Down, Durlston CP East, Townsend Quarry, Ham Common, Kinson Common, Stour Valley

Foodplants:

First brood: Holly. Second brood: Ivy

Behaviour:

Patrol

Atlas: Distribution map & population trends

 

Silver-studded Blue

Plebejus argus

Silver-studded BlueSilver-studded Blue from the side, showing the silver studs
When to see:

End June to End August.
Peak: July

Habitat:

Heathland rides/firebreaks or limestone grassland (calcareous)

Where to see:

Higher Hyde, Studland, Tadnoll, Portland Broadcroft, Portland Tout, Avon Heath Country Park, Sopley Common, Slop Bog

Foodplants:

Heathers (mainly Erica tetralix), Gorse, Birdsfoot Trefoil

Behaviour:

Patrol

Atlas: Distribution map & population trends

 

Small Blue

Cupido minimus

Small Blue butterfly with wings openSmall Blue butterfly on a man's shoe Small Blue with open wingsA pair of Small Blues mating on a kidney vetch flower

Photos: Chris Becker; Michael Barnes; Ken Dolbear; Richard Belding

Comments:

A very small butterfly, as can be seen from the photo on the top right which shows it on a man's shoe.

The upper wings are brown with a white fringe; the male has a dusting of blue. The undersides are pale blue/grey with small black spots. The mating pair are on a kidney vetch flower, which is the foodplant for their caterpillars.

When to see:

Early May to End June. Mid to End August.
Peak: Late May to Late June

Habitat:

Downland, short turf calcareous areas

Where to see:

Cashmoor, Clubmens Down, Durlston CP West, Portland Broadcroft, Bindon Hill

Foodplants:

Kidney Vetch

Behaviour:

Aggressive/Perch

Atlas: Distribution map & population trends