Lores :
The lores are the areas of a bird's face on either side from the base of the bill to the front of the eyes. The lores do not extend further up or down than the width of the bill base.
Crown :
The portion of a bird's head found between the forehead—demarcated by an imaginary line drawn from the anterior corners of the eyes—and through the "remainder of the upper part of the head", to the superciliary line. The occiput or hindhead, is the posterior part of the crown.
Ear-Coverts :
Small covert feathers located behind a bird's eye, in one to four rows, which cover the ear opening (bird ears have no external features) and may aid in the acuity of bird hearing.
Nape(Hindneck) :
The nape is the back of a bird's neck. The color of the nape will often match either the bird's crown or back, and that color may extend onto the sides of the neck to varying degrees depending on the species.
Mantle :
The forward area of a bird's upper side sandwiched between the nape and the start of the back. However, in gulls and terns, the term is often used to refer to much of the upper surface below the nape.
Scapulars / Humeral Region :
Feathers covering a bird's scapula "at the base of the dorsal wing".
Back :
The exterior region of a bird's upper parts between the mantle and the rump.
Secondaries / Secondary Feathers / Secondary Remiges :
A type of remex flight feather, they are connected to the ulna. In some but not all bird species, the ligaments that bind secondaries to the bone connect to small, rounded projections that are called quill knobs. Secondary feathers remain close together in flight (they cannot be individually separated like the primaries can) and help to provide lift by creating the airfoil shape of the bird's wing. Secondaries tend to be shorter and broader than primaries, with blunter ends. They vary in number from six in hummingbirds, to as many as 40 in some species of albatross. In general, larger and longer-winged species have a larger number of secondaries. Birds in more than 40 non-passerine families are missing the fifth secondary feather on each wing; a state known as diastataxis.
Tertials / Tertiaries / Tertiary Feathers / Humeral Feathers :
A type of feather arising in the brachial region, i.e., "proximal to the innermost secondaries", usually growing in a grouping of three to four feathers. They are not considered true remiges as they are not supported by attachment to the corresponding bone—in this case the humerus. These elongated "true" tertials act as a protective cover for all or part of the folded primaries and secondaries, and do not qualify as flight feathers as such. However, many authorities use the term tertials to refer to the shorter, more symmetrical innermost secondaries of passerines (arising from the olecranon and performing the same function as true tertials) in an effort to distinguish them from other secondaries. The term humeral is sometimes used for birds such as the albatrosses and pelicans that have a long humerus.
Rump :
Topographically, the region of a bird's upperparts between the end of the back and the base of the tail. Anatomically, the fleshy protuberance visible at the posterior end of a bird. Its swollen appearance results from it housing the uropygial gland.
Uppertail Coverts :
Covert feathers covering the base of the tail on its upperside. Sometimes these coverts are more specialized. The "tail" of a peacock is actually very elongated uppertail coverts.
Primaries / Primary Feathers; Primary Remiges :
The distance that a bird's longest primaries extend beyond its longest secondaries (or tertials) when its wings are folded. As with wing formulae, this measurement is useful for distinguishing between similarly plumaged birds; however, unlike wing formulae, it is not necessary to have the bird in-hand to make the measurement. Rather, this is a useful relative measurement—some species have long primary extensions, while others have shorter ones. Among the Empidonax flycatchers of the Americas, for example, the dusky flycatcher has a much shorter primary extension than does the very similarly plumaged Hammond's flycatcher. Europe's common skylark has a long primary projection, while that of the near-lookalike Oriental skylark is very short. As a general rule, species which are long distance migrants will have longer primary projection than similar species which do not migrate or migrate shorter distances.
Tail (Rectrices):
While the underlying structure of the tail is made up of bone (the pygostyle) and flesh, the term "tail" is most commonly used to refer to the feathers growing from the region and the shape they form—that is, undertail and uppertail coverts and rectrices, commonly radiating in a fan configuration.
Undertail Coverts :
Covert feathers covering the base of the tail on its underside.
Vent :
The external opening of the cloaca.
Primary Coverts :
Primary coverts are on the outer wing, which overlay the primary flight feathers, Cover the base of the Primaries.
Thigh :
The topographical area between the "knee" and the trunk of the body.
Belly / abdomen :
The topographical region of a bird's underparts between the posterior end of the breast and the vent.
Flanks :
The topographical region of the underparts sketched "between the posterior half of the abdomen and the rump".
Tarsus / Tarsometatarsus :
The third and most conspicuous portion of the bird's leg, from which the toes spring; the foot. In birds, the true tarsus has disappeared, with the proximal tarsals having fused with the tibia, the centralia having disappeared, and the distal bones having fused with the metatarsals to form a single tarsometatarsus bone, effectively giving the leg a third segment.
Greater Coverts : The greater coverts are formed of a single row of larger feathers adjacent to and overlying the bases of the primaries and secondaries.
Alula :
A small, freely-moving projection on the anterior edge of the wing of modern birds (and a few non-avian dinosaurs)—a bird's "thumb"—the word is Latin and means 'winglet'; it is the diminutive of ala, meaning 'wing'. Alula typically bear three to five small flight feathers, with the exact number depending on the species. The bastard wing normally lies flush against the anterior edge of the wing proper, but can be raised to function in similar manner to the slats of airplane wings that aid in lift by allowing a higher than normal angle of attack. By manipulating the alula structure to create a gap between it and the rest of the wing, a bird can avoid stalling when flying at low speeds or when landing. Feathers on the alular digit are not generally considered to be flight feathers in the strict sense; though they are asymmetrical, they lack the length and stiffness of most true flight feathers. Nevertheless, alula feathers are a distinct aid to slow flight.
Breast :
The topographical region of a bird's external anatomy between the throat and the belly.
Median Coverts :
The median coverts are a single row of feathers just proximal to the greater coverts.
Lesser Coverts :
In larger birds, the last few distinct rows of feathers lying between the marginal coverts and the larger (greater and median) coverts are called the lesser coverts.
Throat :
The triangular area of a bird's external anatomy, typically feathered, located between the chin and the upper part of the breast.
Chin :
A small feathered area located just below the base of the bill's lower mandible.
Forehead :
The portion of a bird's head extending "up and back from the bill to an imaginary line joining the anterior corners of the eyes".
