Bird Feather Identification: Type, Size, Pattern

To identify a feather you found, work out where on the bird it grew, measure it, and then match its pattern and color. The US Fish and Wildlife Service's Feather Atlas, run by the National Fish and Wildlife Forensics Laboratory, is an image database of the flight feathers of 438 North American bird species, and its identification tool follows exactly that order:

• Pattern: unpatterned, two-tone, mottled, barred, spotted, iridescent, dark tip or pale tip. More than one can apply.
• Color: the most noticeable color, such as white, black, black and white, brown, gray, blue or purple, green, yellow or orange, red or rufous, or pink.
• Size: small (8 cm or 3 inches or less), medium (8 to 16 cm), large (16 to 24 cm) or huge (over 24 cm, 10 inches).
• Position: primary wing feather, secondary wing feather, tail feather, or all if you do not know.
• Bird group: optional, such as waterfowl, raptors, owls, woodpeckers or songbirds.

The atlas covers flight feathers, meaning wing and tail feathers. Small fluffy body feathers are much harder to match to a species.

The position filter matters, and you can usually decide it by laying the feather flat and comparing the two sides of the shaft.

• Primary wing feathers are the longest and narrowest wing feathers and are strongly asymmetrical: the vane on one side of the shaft is clearly narrower than the other. They attach to the bird's "hand" and give thrust.
• Secondary wing feathers are shorter and broader than primaries, with blunter ends.
• Tail feathers (rectrices) are always paired, most species have six pairs, and they are closer to symmetrical than primaries.

Those descriptions come from the standard anatomy of flight feathers summarized on Wikipedia. A curved, narrow, lopsided feather is a primary; a straight, even feather with a squared or rounded tip is most likely from the tail. A soft, small feather with a fluffy base is a body feather.

The Feather Atlas states that in the United States it is illegal to possess feathers from most native birds without proper permits. The legal basis is the Migratory Bird Treaty Act of 1918, which, as the US Fish and Wildlife Service describes it, prohibits the take (including killing, capturing, selling, trading and transport) of protected migratory bird species without prior authorization; the protected species are listed in federal regulations at 50 CFR 10.13. Eagles have their own law: the Bald and Golden Eagle Protection Act prohibits taking bald or golden eagles, including their parts and feathers, without a permit.

The rule exists because feathers cannot be told apart by where they came from, so allowing possession of found feathers would make illegal trade impossible to police. In practice: photograph the feather where you found it, measure it, and leave it. The photo is all you need for an identification.

Lay the feather flat on a plain, contrasting surface and shoot straight down with a ruler along its length, so the size class is unambiguous. Take one photo of the upper side and one of the underside, since patterns can differ. Include the base of the shaft, which shows whether it is a flight feather or a body feather. NatureLens gives free scans every day, so you can photograph the plant or sign and get a suggested name in seconds, then confirm it with the checks on this page.