§ Terms used across the plates
A glossary of field terms
Every measurement word and topography term used in the register, defined once — so the data on each plate reads exactly the way a guide intends it.
12 terms
Standard usage
- Wing chord
- Wing bent at the wrist, measured from the carpal joint to the tip of the longest primary — the standard skin measurement.
- Culmen
- The dorsal ridge of the upper mandible, from the forehead feathering to the bill tip; the standard bill-length metric.
- Supercilium
- The “eyebrow” stripe running from the bill base, above the eye, toward the rear of the head.
- Primaries
- The outer flight feathers attached to the “hand”; numbered distally, P1 (inner) to P10 (outer).
- Rectrices
- The long, stiff tail feathers (singular: rectrix) — their shape gives the raven's wedge and the crow's fan.
- Hackles
- Erectile, often elongated throat feathers — the shaggy hackles of the Common Raven are diagnostic.
- Nape
- The back of the neck, where the head colour meets the mantle.
- Lores
- The areas on each side of the face between the bill base and the front of the eye.
- Tarsus
- The most conspicuous (lower) segment of the leg, from which the toes spring; a standard measurement.
- Crest
- Elongated, erectile crown feathers raised in display — the cardinal's pointed crest, the Blue Jay's.
- Prebasic molt
- The molt that produces the basic (non-breeding) plumage — modern Humphrey-Parkes terminology.
- AOU code
- The four-letter alpha code for a species — GBHE, CORA, NOCA — used on every register row.
