UK Damselfly Identification Guide
To identify a UK damselfly, first place it in a broad group by wing shape and resting posture, then compare eye color, leg color, shoulder stripes, abdominal markings, habitat, and flight season. Do not name every small blue male from color alone. Common blue, azure, blue-tailed, variable, red-eyed, and small red-eyed damselflies need clear views of different body segments.
Is It a Damselfly?
Damselflies usually have a slender abdomen, clearly separated eyes, and forewings and hind wings of similar shape. Most fold the wings over the abdomen while perched. Spreadwings are the main posture exception, while demoiselles have broader, often colored wings.
Wait for the insect to settle. Identification from flight alone is difficult, and a distant metallic body could belong to a damselfly, beetle, or other insect.
Which Group Does It Belong To?
Broad-winged demoiselles are large damselflies associated with running water. Emerald damselflies and other spreadwings rest with their wings partly open. The remaining narrow-winged pond damsels include blues, reds, red-eyes, blue-tails, and related species.
The British Dragonfly Society checklist gives accepted English and scientific names. Use it to verify that a candidate currently occurs in Britain before comparing tiny markings.
How Do You Separate Blue Damselflies?
Photograph the second abdominal segment just behind the thorax. A mature male common blue typically has a rounded black mark linked to the rear black band. Azure damselfly markings often resemble a U, while variable damselflies can show a goblet-like form. Patterns vary, so check shoulder stripes and side markings too.
The BDS garden guide illustrates the common blue mark and habitat. A blue female or teneral adult may not match the classic mature male plate.
How Do You Recognize a Blue-Tailed Damselfly?
Male blue-tailed damselflies are mostly dark along the abdomen with a bright blue segment near the tip. The thorax carries a narrow colored shoulder stripe. Females have several color forms, including violet, orange, greenish, and blue stages.
Scarce blue-tailed damselfly can look similar but differs in the position and extent of the tail color and favors specialized shallow habitats. Photograph the complete abdomen and ask for expert review when the site supports both.
How Do You Separate the Red-Eyes?
Male red-eyed and small red-eyed damselflies have red eyes, dark bodies, and blue near the tip. The larger Erythromma najas usually lacks full shoulder stripes and has blue mainly on segments nine and ten. E. viridulum has short shoulder stripes and additional blue on the sides of segment eight.
The BDS red-eyed profile places the species on floating leaves at lakes, gravel pits, canals, and slow rivers. Habitat and perch choice support the structural evidence.
Which Red Damselfly Is It?
Large red damselfly is widespread, relatively sturdy, black-legged, and often appears early in spring. Small red damselfly is finer, red-legged, more localized, and associated with shallow acidic wetland habitat.
The BDS large red feature shows how sex and female color form complicate a quick match. Check the side of the thorax as well as the abdomen.
Does Season Settle the Identification?
No, but it can remove unlikely options. Flight periods overlap and shift with latitude, elevation, and annual weather. An early date supports large red damselfly, while a late summer red-eye may fit more than one species.
Use current regional records instead of treating a calendar bar as a hard boundary. A rare out-of-range record deserves better photographs and independent verification, not automatic rejection.
How Should You Report a Sighting?
Submit the original uncropped images with coordinates, date, number seen, sex if certain, and a short habitat description. Preserve the camera timestamp and do not sharpen a tiny subject until markings appear that were not in the original pixels.
For an unusual species, let a county recorder see the full evidence before publicizing an exact sensitive location. A verified record can improve distribution and flight-period knowledge; an unsupported confident label creates work for later reviewers.
What Should You Photograph?
- Take a dorsal image showing the shoulder stripes and abdomen base.
- Take a side image showing the face, legs, and thoracic sutures.
- Keep the last three abdominal segments sharp.
- Record sex if known, but do not guess from color alone.
- Note county, date, water type, and dominant aquatic plants.
A feeding observation can add useful behavior. For that part of the record, see what damselflies eat.
