Butterfly ID: Families, Wing Marks and Moth Look-Alikes

• Antenna shape: butterfly antennae are long and thin with a knob on the end, distinguishing them from moths.
• Contrast (moths): moths are typically night-active, drab-colored, and have feathery or spindle-shaped antennae.
• Resting posture: butterflies typically hold their wings vertically together over the body when at rest.
• Contrast (moths): moths typically fold the front and hind wings into a V-shape when at rest.

People most often mix butterflies up with:

• Moths

Open the other page and compare its list against the marks above; the differences are usually in the antennae, wings or the way the body is divided.

Butterflies pollinate flowering plants and serve as food for other organisms, forming an important link in the food chain; they are considered beneficial.

Commonly found in sunny, wind-sheltered garden settings, especially where host plants and nectar plants are grown.

Get as close as your camera will focus, from directly above, in daylight or a bright lamp. Include the whole body with the legs and antennae in frame; a second shot from the side shows wings and body segments. Put a coin or ruler next to it for scale. For a bite or a bug found on skin or bedding, photograph the bug itself, not the mark. The app names the likely group; use the list above to confirm.

• Confirm it is a butterfly. Butterflies have long, thin antennae with a knob on the end and fly mostly by day (University of Kentucky). At rest many hold their wings upright over the body, while most moths fold them in a V (Texas A&M).
• Place it in a family. Tails on the hindwings, an all-white or yellow colour, only four legs in use, or hooked antenna tips each point to a different family (see below).
• Photograph both sides. A butterfly resting with its wings closed shows only the underside, so try to get the upper side as well when it opens its wings.
• Use place and date. ButterflyIdentification.org lists North American butterflies by US state, which shortens the list of possible species quickly.

Wikipedia's butterfly article puts the world's butterflies at about 18,500 to 20,000 species in seven families:

• Swallowtails (Papilionidae): often have tails on the hindwings; the caterpillar can push out a foul-tasting organ called an osmeterium.
• Whites and sulphurs (Pieridae): mostly white, yellow or orange.
• Blues, coppers and hairstreaks (Lycaenidae): small and brightly coloured, often with a false head made of eyespots and small tails.
• Metalmarks (Riodinidae): often have metallic spots on the wings and bold black, orange and blue colouring.
• Brush-footed butterflies (Nymphalidae): the front legs are reduced, so they appear to stand on four legs; often brightly coloured.
• Skippers (Hesperiidae): small, with darting flight and antenna clubs hooked backwards.
• Moth-butterflies (Hedylidae): small and brown like geometrid moths, with antennae that are not clubbed.

The Missouri Department of Conservation counts about 275 skipper species in North America north of Mexico: roughly 130 to 140 grass skippers and about 100 spread-wing skippers and their relatives. Nearly all have club-tipped antennae bent like a hook, and short, chunky bodies. Grass skippers perch with the forewings raised in a V and the hindwings held flat, a shape described as a jet plane; spread-wing skippers land with all four wings flat out to the sides. Skippers walk on all six legs, while brush-footed butterflies walk on four. Geometrid moths also rest with flat wings but have narrow bodies and no hooked clubs. Compare with moths.

• Antennae: clubbed in butterflies; thread-like or feathery in moths (Wikipedia; University of Kentucky).
• Resting wings: held upright over the back in many butterflies; flat or folded over the body in moths (Wikipedia; Texas A&M).
• Time of day: butterflies are mostly active by day, most moths at night (University of Kentucky).
• Pupa: butterflies pupate in a bare chrysalis; many moths spin a protective cocoon (Wikipedia).
• Exceptions: skippers and moth-butterflies blur the line, and some moths fly by day (Wildlife Trusts).

Photograph the butterfly from the side while it rests with wings closed, then again from above if it opens them. Include the antennae and any tails. Photograph it and InsectLens identifies it. You can then confirm the family using the marks on this page and check the species against ButterflyIdentification.org's state lists or its side-by-side comparison tool.

A butterfly identification chart works by colour first, then one or two marks. The Wildlife Trusts' guide to common British garden butterflies groups them this way:

• Red or orange: peacock, red admiral, small tortoiseshell, painted lady and small copper.
• White: large white, small white and green-veined white.
• Yellow: brimstone.
• Brown: meadow brown and speckled wood. The speckled wood is the only brown butterfly with three small cream-ringed eyespots on each hindwing and one on each forewing.
• Blue: holly blue and common blue.

For North America, Eleanor Lutz's animated butterfly identification chart shows 42 species with their ranges, and ButterflyIdentification.org lists species by state. The Wildlife Trusts also note that an overcast day is a good time to look closely, because butterflies are less active and stay still for longer.

• Orange with black veins: in North America this is often a monarch or a viceroy. The viceroy looks very similar; both are distasteful to predators and share the warning pattern (Wikipedia).
• White: look at the wing tips and the veins, and compare large, small and green-veined whites in a guide for your region.
• Brown: count the eyespots on the hindwing, as with the speckled wood above.
• Blue: photograph the underside as well as the upper side, because a butterfly resting with closed wings shows only the underside.
• Any colour with a hooked antenna club and a chunky body: probably a skipper; see the family section above.

Some butterflies are poisonous to eat, and they usually advertise it. Monarch caterpillars feed only on milkweed and store its cardiac glycosides, and both caterpillars and adults use bright contrasting colours to warn predators that they taste bad and are poisonous (Wikipedia). The viceroy shares the monarch's orange and black pattern and is itself distasteful. Bold orange, red or black and white patterns on a butterfly can be this kind of warning to predators. Do not eat any butterfly or caterpillar, and keep them away from pets; if a child or pet swallows one and seems unwell, call a doctor or vet, or Poison Help (1-800-222-1222) in the US. For caterpillars that sting or irritate skin, see caterpillars.

• Seek by iNaturalist: released in spring 2018, marketed to families, needs no online account and lets observations stay private (Wikipedia).
• iNaturalist: its automated identification tool, first released in 2017, uses a computer vision model trained on iNaturalist observations; the community then checks records, and good ones become Research Grade (Wikipedia).
• Google Lens: compares the objects in your picture with other images and ranks them by similarity, so treat the top answer as a lead (Google).
• InsectLens: photograph the butterfly and the app names it, then check the family and colour marks on this page.