Adult old, mature bird in definitive plumage. It is not possible to know its exact year of birth
Alula a group of feathers, usually three, attached at the digital bone, near the wing-bend on upper forewind.
Autumn in wide sense, period that goes from the end of the moult until December 31st.
Breeding plumage colorful plumage gained by many birds for breeding period, primarily males, through abrasion or in a prebreeding moult.
Carpal wing feather placed between greater coverts and alula.
Cere bare skin on the base of upper mandible and around nostrils; it's usually coloured in adult birds and in breeding time.
Complete moult all feathers of the body, wings and tail are changed.
Crown upper part of the head.
Eclipse plumage cryptic, female-like plumage attained by male ducks in summer
Emargination a step or abrupt narrowing of the web of a feather, occuring towards the tip of the outer web of the feather.
Eye-ring a ring of bare, unfeathered skin, around the eye, usually coloured.
First year age category referring to the first year of the life of the bird, from hatching until December 31st.
First year autumn (1st year autumn) age category referring to the first autumn of the life of the bird, from its postjuvenile moult until December 31st.
Flight feathers the long quills on the wing, primaries, secondaries and tertials.
Greater coverts wing feathers covering the bases of secondaries.
Juvenile fledged bird wearing the first set of true feathers, but which has not yet moulted any of these feathers.
Lesser coverts small feathers placed upper wing, near the median coverts.
Median coverts small feathers placed in the middle of the wing, between greater coverts and lesser coverts.
Moult a natural process of renewal of the plumage, whereby the old feathers are shed and new ones grown; moult pattern is very different between species or between different ages in the same species.
Moustachial stripe, moustache usually narrow stripe, often dark, running from near the base of the lower mandible and along the lower edge of the cheek.
Partial moult not all feathers of the body, wings or tail are changed; some are retained.
Postbreeding moult moult taking place after breeding period; most of the small birds acquire the adult plumage in their first postbreeding moult.
Postjuvenile moult first moult where all or part of the juvenile plumage is lost.
Prebreeding moult moult taking place late winter, before the breeding period; some species acquire their breeding plumage.
Primaries the quills growing on the outer wing, the part of the wing outside the wing bend.
Primary coverts wing feathers covering the bases of primaries.
Rectrices the main tail feathers.
Retained feathers unmoulted feathers which remain on wings or tail after a moult.
Rump feathers placed on lower back, nearest the tail.
Scapulars feathers covering the shoulder of birds.
Second year (2nd year) age category referring to the second year of life of the bird, from January 1st until December 31st.
Second year autumn (2nd year autumn) age category referring to the autumn on the second year of life of the bird, from its second moult until December 31st.
Second year spring (2nd year spring) age category referring to the spring on the second year of life of the bird, from January 1st until its second moult.
Secondaries the quills growing on the inner wing.
Shaft the main axis of a feather where webs grow.
Speculum distinctive, glossy patch on upper secondaries, often in ducks.
Spring in wide sense, period that goes from the January 1st until the end of the moult.
Suspended moult a temporary interruption which is subsequently resumed at the point of interruption; usually due to migration.
Tertials the innermost wing feathers, usually with somewhat different shape and pattern; they are three in small birds.
Third year (3rd year) age category referring to the third year of life of the bird, from January 1st until December 31st.
Third year autumn (3rd year autumn) age category referring to the autumn on the third year of life of the bird, from its third moult until December 31st.
Third year spring (3rd year spring) age category referring to the spring on the third year of life of the bird, from January 1st until its third moult.
Undertail coverts small feathers covering the base of rectrices on the underside of the tail.
Underwing coverts small feathers covering the base of long feathers on the underside of the wing.
Uppertail coverts small feathers covering the base of rectrices on tail.
Web the barbs on each side of the shaft of a bird's feather.
Wing coverts small feathers covering the wings.
Young a young bird before acquiring the first set of true feathers.