Birds of the World

COAST BIRDS
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WORLD BIRDS
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ANECDOTES

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TRAITS
 Ratites
 Tinamous
 Cracids/Galli
 Waterfowl
   Screamers
   Ducks

 Penguins
 Loons
 Grebes
 Procellarids
   Albatrosses
   Petrels
   Storm-Petrels

Totipalmate Swm

   Tropicbirds
   Gannets/Boobies
   Pelicans
   Cormorants
   Anhingas
   Frigatebirds

 
Waders
   Herons
   Ibises
   Storks  

 NW Vultures
 Flamingos
 Raptors
 Gruiformes
   Buttonquail
   Bustards
   Cranes
   Rails

 Shorebirds
   Sandgrouse
   Plovers
   Oystercatchers
   Stilts
   Sandpipers
   Gulls/Terns
   Auks

 Pigeons
 Parrots
 Turacos
 Cuckoos
 Owls
 Frogmouths
 Nightjars
 Swifts/Humbd
 Colies
 Coraciae

   Hornbills
   Hoopoes
   Trogons
   Rollers
   Kingfishers
   Bee-eaters
   Jacamars/Puffbd

 
Pici
   Honeyguides
   Woodpeckers
   Barbets/Toucans

PASSERINES
   NZ WRENS
   OW SUBOSC

      Broadbills
      Pittas

 NW SUBOSC
   NW Flycatchers

   Becards
   Cotingas
   Manakins
   Antbirds
   Ovenbirds
   Woodcreepers
   Antthrushes
   Tapaculos 

 OSCINES
 Lyre-/Scrub-birds
 Bowerbirds
 Aust. Wrens
 Honeyeaters
 Scrubwrens
 Aust. Robins
 Kinglets
 Shrikes
 Vireos
 Whistlers
 Corvids
 Birds-of-Paradse
 OW Orioles
 Cuckoo-shrikes
 Fantails
 Drongos
 Monarchs
 Bush-shrikes
 Wattle-eyes
 Vangas
 Waxwings
 Dippers
 Thrushes
 OW Flycatchers
 Starlings
 Mimids
 Nuthatches
 N Creepers
 Wrens
 Gnatcatchers
 Tits/Parids
 Larks
 Swallows
 Leaf-Warblers
 Bulbuls
 Cisticolas
 White-eyes
 Babblers
 OW Warblers
 Flowerpeckers
 Sunbirds
 OW Sparrows
 Accentors
 Pipits
 Estridids
 Weavers
 Whydahs
 9-prim. Oscines

   Fringillines
   Carduelines
   Hawaiian Honycrp
   NW Sparrows
   NW Warblers
   Tanagers
   Cardinals
   NW Blackbirds

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TRAITS
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Skeletal Features
  Palatal Structure
  External Nares
  Nasal Bones
  Columella
  Cervical Vertebrae
  Sternum

Legs and Feet
  Tarsometarsus
  Toes
  Feet
Development
Internal Features
  Supraorbital Gland
  Syrinx
  Intestinal Convolutions
  Intestinal Caeca
  Carotid Arteries
  Thigh Artery
Feathers and Skin
  Pterylosis
  Aftershaft
  Natal Down
  Number of Flight Feathers
  Wing Formula
  Fifth Secondary
  Powder Down
  Oil (Uropygial) Gland
  Rhamphotheca
Muscular Features
  Pelvic Musculature
  Deep Plantar Tendons
  Jaw Muscles
  Other Muscles
Other Features
   
 

Skeletal Features

 
  Palatal Structure
  Huxley (1867) proposed four palatal types useful in characterizing higher categories or carinate birds (birds with keeled sterna). These are dromaeognathous (palaeognathous), desmognathous, schizognathous, and aegithognathous. A fifth type was proposed by Parker in 1875.
   Dromaeognathous - prevomers (vomers) extend far back and articulate with the posterior ends of the palatines or anterior ends of the pterygoids, thus separating both from the parasphenoid (basisphenoid). Huxley placed on the tinamous in the order Dromaeognathae but later authors considered the palates of all of the ratites to be "paleognathous." DNA hybridization studies verify this conclusion. 
   Schizognathous - (pre)vomer sometimes small and completely fused, usually terminating in a point. The maxillopalatines are variable, but do not meet in mid-line with each other or with the vomer. Palatines and pterygoids articulate with the parasphenoid rostrum. Characteristic of grouse,cranes, gulls, snipe, woodpeckers, and others. 
   Desmognathous
- (pre)vomer fused and small or absent. Maxillopalatines meet in the mid-line (and often fuse). The pterygoids and palatines articulate with the (para-)basisphenoidal rostrum. Found in pelicaniforms, waterfowl, waders (herons), raptors and some others (birds which feed on large and active animal prey).
   Aegithognathous - (pre)vomer broad. fused and truncates anteriorly. The maxillopalatines do not join but do touch the basisphenoidal rostrum. Characteristic of passerines and swifts.
   Saurognathous - small maxillopalatines - skull is widely schizognatous - some woodpeckers. This is not one of Huxley's original skull types.

   In studying the variety of palatal structures shown by modern birds, the last three palate types may merge and it is not always easy to assign a type to the palate under study. Young birds actually develop a dromaeognathous palate first which then matures to their characteristic type.
   Bock (1963) studied the skulls of the Eoaves and redefined the paleognathous palate which is similar in all birds in which it is found and is distinct from the palate of all other birds, reaffirning the evidence for affinities among the ratites (also confirmed by DNA-DNA hybridization studies).
   It should be considered that, at least to some extent, palatal conditions reflect adaptations to different food types rather than or in addition to phylogeny.
 
Palaeognathous palate
Schizognathous palate
Green = maxillopalatine
Red = prevomer
Blue = Pterygoid

  The dromeognathous (= palaeognathous) palate found in the rhea,  Rhea americana. A schizognathous palate found in the Laughing Gull- Larus atricilla.  
 
Desmognathous palate
Aegithognathous palate

Images from
J. van Tyne and A. J. Berger. 1976. Fundamentals of Ornithology.
2nd ed. John Wiley & Sons, New York.
© University of Michigan, Museum of Zoology.

  The desmognathous palate found in the Canada Goose, Branta canadensis. An aegithognathous palate found in the Common Raven, Corvus corax  
 
  External Nares
     Pervious - nostrils are open to the exterior
   Gymnorhinal - exposed in most birds (concealed by feathers in grouse and crows)
   Impervious (obsolete) - nostrils close during development (penguins, frigatebirds, cormorants, anhingas, sulids, etc.)
   Nostrils are usually placed laterally on the bill, somewhere behind the mid-point, but their position ranges from the tip (kiwis) to the posterior edge of the bill (toucans -their nostrils open to the rear). They are be round, oval, or slit-like. In procellariids, nostrils are at the end of horny tubes and in many nightjars the are at the end of long, flexible tubes. The nasal operculum is a flap-like structure on the upper rim (fowl, seed-snipe, doves, etc.). The operculum is moveable in Rhinocryptidae. In wrynecks, the flap attaches ventrally. Etc.
   The condition of the nasal septum (the bony and horny plate separating the two nasal cavities) also varies. It may be
   Perforate - it is open and you can see through the bill (rails, cranes, vultures, Forsters' Tern, etc.)
   Imperforate - closed septum - most birds
 
  Nasal Bones
 
Garrod (1873) described the following arrangements of the nasal openings in the skull.
   Holorhinal (A) - nostril entire, not deeply cleft - the posterior outline is fairly rounded, The posterior end of the opening passes across the nasal processes of the premaxilla. Most groups including rails, grouse, pheasants.
  Schizorhinal (D) - posterior edge of the nostril cleft forms a deep slit that extends to or beyond the premaxillaries. Doves, gulls, plovers, cranes, auks.

   Later, two additional categories were added:
   Pseudoschizorhinal - the posterior outline of the opening is rounded but the opening extends posterior to the nasal processes of the premaxilla - found in some ovenbirds (Furnariidae)
   Amphirhinal - two openings, one anterior to the other, on each side. Found in more than 15 passerine families and not really useful in making taxanomic inferences.
Nostrils
      © University of Michigan, Museum of Zoology.
 
  Columella
  Birds have a single bone in the middle ear. Feduccia (1974) uses this trait to support monophyly among Old and New World suboscines.
 
  Cervical Vertebrae
  Mammals (almost all) have but 7 cervical vertebrae. In birds, the neck constitutes a flexible connection between a compact body and their head where the principal sense organs are located. Birds have between 13 (some passerines and cuckoos) and 25 (some swans) cervical vertebrae. Most have 14-15.
   The more posterior cervical vertebrae may bear  incomplete cervical or cervico-dorsal ribs but should be included in the count of cervical elements.
   In Anhingas, the 8th and 9th cervical vertebrae are modified to allow a "S" shaped curve with the angle at the 8th vertebra. When contracted, a muscle inserting on the 8th vertebrae thrusts the neck and head sharply forward enabling the "darter" to spear a fish. In herons and bitterns, the 6th cervical vertebra is elongate and articulates so the neck folds in an "S" shaped curve (herons and bitterns typically fly with the neck folded, not extended as in ibises and storks).
   The atlas in birds contains a foramen or notch in its body into which the odontoid process of the axis articulates (to give a "perforated" or "notched" atlas).
 
  Sternum
    Ratites (Order Struthioniformes) are large flightless birds with a smooth, unkeeled sternum.
In most birds, the body of the sternum gives rise to a carina or keel which anchors the origins of the major flight muscles of the wing (pectoralis and supracorcoideus). The size of the keel is related to the mass and strength of the flight muscles. These birds are known as carinates.
   At its anterior end, the sternum has two midline projections, the spina interna and spina externa (these may fuse in some birds). Behind the rib facets, there is usually at least one process, giving rise to several types of sterna:
   notched - single- or double-notched
   fenestrate - small openings only
   entire - no notches or windows
   These characters have not led to important taxonomic decisions.
   In ratite birds (and flightless birds such as the New Zealand parrot Strigops and the rail Notornis) there is virtually no keel on the sternum. Like the parrot and rail that lost the keel with the loss of flight, ratites probably descended from flying ancestors.

Sternum

Several types of sternal variation ranging from
   A. a simple notch (Psorocolius - an icterid)
   B. double notches (Megaceryle - a kingfisher) to
   C. incised (Callipepla - a pheasant).