Black-tailed Skimmer - Orthetrum cancellatum

Adult size

Overall length: 44 - 50mm   Hindwing length: 35 - 40mm

Distinguishing features

The larger of the two skimmer dragonflies. Characteristically both species are long and narrow in appearance. They will happily perch on open ground, rocks and logs and have a ‘hunched’ appearance as their wings tend to point forward. Male has black on last 4 abdominal segments.

Identification - for help with terms see glossary

Mature male

Male have power-blue pruinescence on a slender tapering abdomen which becomes black from segment 7 – 10 with small orange marks. Thorax is brown with no stripes and eyes are blue. Wings have no dark patches on them.

Immature male

Resembles immature female, having a black ‘ladder’ pattern on abdomen. However thorax is yellow and eyes are pale brown.

Mature female

Abdomen is rich ochre yellow with distinctive black ‘ladder’ pattern. Thorax and eyes are olive green in colour. With age the abdomen can become dull olive-brown in colour.

Immature female

Similar to immature males, only examination of anal appendages can separate them at this early stage.

Habitat

This species seems to favour larger open water bodies such as lakes, large ponds, gravel and clay pits, and also slow flowing rivers with partially exposed margins on which to bask and defend territories. Can tolerate brackish conditions.

Behaviour

As with the Keeled Skimmer and darter dragonflies they will tend to perch on bare exposed surfaces such as bare mud, stones and logs. Wings tend to point forward when at rest. Males are very territorial and aggressively defend their patches from intruders.

Status and distribution

Essentially a southern species but is expanding its range northwards. Can be numerous when habitat is suitable. Can be locally common at some sites in Dorset.



Flight period

Main flight period is April to September peaking in June and July.

Similar species

The male could be confused with  Keeled Skimmer, but the black 'tail' with separate them. Scarce Chaser males have a similar blue abdomen with a black tail but they have dark wing patches and the thorax is black.

More photographs

Click on the photos below to enlarge...

All photographs by kind permission & © of Ken Dolbear unless otherwise stated. All rights reserved.