BIO 554/754
Ornithology

External Structural Characters


Terms to describe bills | Terms to describe feet | Terms to describe toes | Terms to describe nails | Terms to describe tarsi
Terms to describe tails | Feathers - Shape & Structure | Nostrils | Modified feathers


Be able to define & identify the following terms: 

Terms to describe bills
  long
  short
  hooked
  crossed
  compressed
  depressed
  stout
  terete
  straight
  recurved
  decurved
  bent
  swollen
  acute
  chisel-like
  toothed
  serrate
  gibbous
  spatulate
  notched
  conical
  lamellate
  angulated commissure
  gular sac
Terms to describe feet
  anisodactyl
  syndactyl
  heterodactyl
  zygodactyl
  pamprodactyl
  raptorial
  semipalmate
  totipalmate
  palmate
  lobate

Terms to describe tarsi
  scutellate
  reticulate
  scutellate-reticulate
  booted
  scutellate-booted
  spurred

Terms to describe toes
  incumbent
  elevated

Terms to describe nails
  acute
  obtuse
  lengthened
  pectinate
  flattened
 

Terms to describe tails
  long
  short
  square
  rounded
  graduated
  pointed
  emarginate
  forked

Feathers - Shape & Structure
  notched
  spinose
  acuminate
  attenuate

Nostrils
  imperforate
  perforate
  tubular
  operculate
  linear
  oval
  circular

Modified Feathers
  horns
  crests
  ruffs
  pinnae
  ears
  facial disc
  speculum
  rictal bristles


Terms to describe bills:
 

Long: the bill is much longer than the head, as in a Sword-billed Hummingbird (Ensifera ensifera).
Short: the bill is much shorter than the head, as in a redpoll.
Hooked: the upper mandible is longer than the lower, and its tip is bent over the tip of the lower, as in a hawk.
Crossed: the tips of the mandibles cross each other, as in a crossbill (check: How Nature Works: White-winged Crossbill Feeding Technique).
Compressed: the bill for a good part of its length is higher than wide, as in a puffin 
Depressed: the bill is wider than high, as in a duck.
Stout: the bill is conspicuously high and wide, as in a Gray Partridge.
Terete: the bill is generally circular either in cross-section, or when viewed anteriorly, as in a hummingbird.
Straight: the line along which the mandibles close is in line with the axis of  the head, as in a Great Blue Heron
Recurved: the bill curves upward (e.g., American Avocet)
.
Decurved: the bill curves downward, as in the Brown Creeper (right) or ibises
Bent: the bill is deflected at an angle (usually deflected downward at the middle), as in a flamingo.
Swollen: the sides of the mandibles are convex, as in a tanager
Acute: the bill tapers to a sharp point, as in the Blue-winged Warbler 
Chisel-like: the tip of the bill is beveled
(e.g., Hairy Woodpecker) 
Toothed: the upper mandibular tomium has a "tooth," as in a falcon
Serrate: the bill has saw-like tomia, as in a merganser.
Gibbous: the bill has a pronounced hump, as in a White-winged Scoter.
Spatulate, or spoon-shaped: the bill is much widened, or depressed, towards its tip (e.g., Northern Shoveler) 
Notched: the bill has a slight nick in the tomia of one or both mandibles. Most frequently the notch occurs near the tip of the upper mandible, as in thrushes (like the
American Robin).
Conical: the bill has the shape of a cone, as in a White-crowned Sparrow.
Lamellate, or sieve-billed: the mandibles have just within their tomia a series of transverse tooth-like ridges, as in swans, geese, ducks, & flamingoes.


Upper jaw of (a) the shallow-keeled bill of Chilean Flamingo and (b) the
deep-keeled bill of Andean Flamingo. Lower jaw of (c) the shallow-keeled
bill of Chilean Flamingo and (d) the deep-keeled bill of Andean Flamingo. The
upper jaw of Chilean Flamingo is wider than that of Andean Flamingo, and the
free edge of the keel has a broad central portion uncovered by lamellae.
In Andean Flamingo, the free edge of the keel is almost completely covered by lamellae. The lower jaw of Andean Flamingo has a large lamellated area
in the inner sides of the bill. (1) marginal lamellae, (2) keel covered by inner
submarginal rows, (3) free edge of the keel, (4) serrated ridgelike outer submarginal rows, (5) hillocklike inner submarginals rows, (6) Expanded
inflexed borders of the lower jaw. Letters indicate regions of the bill:
(P) proximal, (C) curvature, (D) distal (Mascitti and Kravetz 2002).

Angulated commissure: the commissure forms a sharp angle at the point where the tomium proper meets the rictus (e.g., Evening Grosbeak)
With gular sac: the chin, gular region, and jugulum are distended, as in a pelican. 


Useful links:

Introduction to Birds - Glossary of Terms

The Bird Site - Bills & Beaks

The Bird Site - Feet


Literature Cited

Mascitti, V. and F. O. Kravetz. 2002. Bill morphology of South American flamingos. Condor 104: 73-83.


Back to BIO 554/754 syllabus