F Glossary of bird terms

feather variations



feather



epidermal growths form distinctive outer covering, or plumage, on birds. considered complex integumentary structures found in vertebrates, and, indeed, premier example of complex evolutionary novelty. feathers among characteristics distinguish extant birds other living groups. although feathers cover parts of body of birds, arise well-defined tracts on skin. aid in flight, thermal insulation , waterproofing, colouration helping in communication , protection. although there many subdivisions of feathers, @ broadest levels, feathers either classified vaned feathers, cover exterior of body , include pennaceous feathers, , down feathers grow underneath vaned feathers. third rarer type of feather, filoplume, hairlike , (if present in bird; entirely absent in ratites) grows alongside contour feathers. typical vaned feather features main shaft called quill upper section called rachis. fused rachis series of branches, or barbs; barbs branched , form barbules branch yet again barbicels, of have minute hooks called hooklets cross-attachment. down feathers fluffy because lack barbicels, barbules float free of each other, allowing down trap air , provide excellent thermal insulation. @ base of feather, rachis expands form hollow tubular calamus inserts follicle in skin. basal part of calamus without vanes. part embedded within skin follicle , has opening @ base (proximal umbilicus) , small opening on side (distal umbilicus) inserts follicle in skin.
feather pecking



a behavioural problem in 1 bird repeatedly pecks @ feathers of another, occurs amongst domestic hens reared egg production, although seen in other poultry such pheasants, turkeys, ducks , in farmed ostriches. 2 levels of severity recognised: gentle , severe .
feather tract
see: pterylae.
fecal sac



also, faecal sac. mucous membrane, white or clear dark end, surrounds feces of species of nestling birds. allows parent birds more remove fecal material nest. nestling produces fecal sac within seconds of being fed; if not, waiting adult may prod around youngster s cloaca stimulate excretion. young birds of species adopt specific postures or engage in specific behaviours signal producing fecal sacs. example, nestling curve-billed thrashers raise posteriors in air, while young cactus wrens shake bodies. other species deposit sacs on rim of nest, seen (and removed) parent birds. not species generate fecal sacs. prevalent in passerines , near relatives, have young remain in nest longer periods.
forehead
the portion of bird s head extending , bill imaginary line joining anterior corners of eyes .


illustration of goose filoplume feather, structure , life of birds (1895).



filoplume
also, filoplume feather; hair feather, thread feather. hairlike type of feather that, if present in bird (they entirely absent in ratites) grows alongside contour feathers. typical filoplume silky in appearance, lacks pith , superior umbilicous opening, has slender, straight shaft lacking differentiation calamus , rachis, , naked or has few barbs (that lack cross-attachment) @ distal end. closely associated contour feathers , entirely hidden them, 1 or 2 filoplumes attached , sprouting near same point of skin each contour feather, @ least on bird s head, neck , trunk. have cluster of sensory copuscles @ base, , thought serve similar sensory function hair in many mammals. filoplumes 1 of 3 major classes of feathers, others being pennaceous , plumulaceous feathers.
flange
also, recurved margin. thickened dorsal edge of bases of pennaceous barbules, recurved in proximal barbules, , in distal barbules anchor hooklets. (see diagram; refer figures 3 [in flange referred folded edge ] , 6 [in mechanism of interlocking between flange , hooklet shown].)
flanks
the topographical region of underparts sketched between posterior half of abdomen , rump .
fledge
also, fledging. stage in young bird s life when feathers , wing muscles sufficiently developed flight, or act of chick s parents in raising time threshold.
fledgling
a juvenile bird during period venturing or has left nest , learning run , fly; period after fledging, when bird still dependent upon parental care , feeding.
flight
most birds can fly, distinguishes them other vertebrate classes. flight primary means of locomotion bird species , used breeding, feeding , predator avoidance , escape. birds have various adaptations flight, including lightweight skeleton, 2 large flight muscles, pectoralis (which accounts 15% of total mass of bird) , supracoracoideus, modified forelimb (wing) serves aerofoil. wing shape , size determine bird species type of flight; many birds combine powered, flapping flight less energy-intensive soaring flight. 60 extant bird species flightless, many extinct birds. flightlessness arises in birds on isolated islands, due limited resources , absence of land predators. though flightless, penguins use similar musculature , movements fly through water, auks, shearwaters , dippers.


parts of feather:





flight feather



also pennae volatus. long, stiff, asymmetrically shaped, symmetrically paired pennaceous feathers on tail or wings of bird; on tail called rectrices (singular rectrix), while on wings called remiges (singular remex). based on location, remiges subdivided primaries, secondaries , tertiaries.
friction barbules
a specialized type of barbule located on distal part of inner vane of primary feathers on wings of flighted birds. friction barbules support lobe-shaped ( lobular ) barbicels broader typical barbicel hosted other vaned feathers, , in turn support more hooklets. theory augmented surface area , other adaptations increases grip through friction when outer web of barbs of 1 primary feather come contact , rub against inner web of barbs of primary feather overlays, thereby preventing slippage during rigors of flight. friction barbules found on parts of primary feathers in zones of overlap neighboring primaries. theory (and use of friction in title of defined phrase) has been criticized. in avian flight (2005), author notes birds open , close wings during every wing beat cycle , , proposes energetic cost overcome friction during wing extension , flexion of each beat cycle prohibitive. offered instead theory function of these specialized barbules lock primary feathers on wings downstroke, during high pressure below wings surface otherwise tend cause feathers spread.
frontal shield



also facial shield; face shield; frontal plate. hard or fleshy plate extending base of upper mandible on forehead of several bird species including water birds in rail family, gallinules , moorhens, swamphens , coots, in jacana. while face shields made of fatty tissues, birds, such turacos, e.g. red-crested turaco, have face shields hard extensions of mandible. size, shape , colour may exhibit testosterone-dependent variation in either sex during year. functionality appears relate protection of face while feeding in or moving through dense vegetation, courtship display , territorial defence. compare: casque.
furcula
also, wishbone; merry-thought. latin little fork , furcula forked bone, found in dinosaurs, located below neck , formed fusion of 2 clavicles. primary function in strengthening of thoracic skeleton withstand rigors of flight. works strut between bird s shoulders, , articulates each of bird s scapulae. in conjunction coracoid , scapula, forms unique structure called triosseal canal, houses strong tendon connects supracoracoideus muscles humerus. system responsible lifting wings during recovery stroke. thorax compressed flight muscles during downstroke, upper ends of furcula spread apart, expanding as 50% of resting width, , contract. furcula may aid in respiration, helping pump air through air sacs.

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