| Length Characteristic |
|
| Long:the bill is decidedly
longer than the head, as in a bittern.
Use: stab prey, the edges are very sharp
for holding the slippery fish
|
|
| Short: the bill
is decidedly shorter than the head, as in a redpoll.
Use: cracking open small seeds
|
|
| Shape Characteristic |
|
| Hooked: the upper
mandible is longer than the lower, and its tip is bent over the tip of the
lower, as in a hawk.
Use: tear prey,
such as mice, into bite-sized pieces with their strong, hooked bills.
|
|
| Crossed:the tips
of the mandibles cross each other, as in a crossbill.
Use: opening pine cones to extract seeds
|
|
| Compressed: the
bill for a good part of its length is higher than wide, as in a puffin or
a kingfisher.
Use: The Puffin has a large
bright red bill which is used
for courtship display.
During the winter the
colorful outside pieces fall off and the bill is
smaller and dull colored.
|
|
| Depressed: the
bill is wider than high, as in a duck.
Use: sifting through muck in search of prey. Also, filtering out animal
or plant material from the water. The combs on the sides of the bill catch
the food which is then removed with
the tongue and swallowed. The nail on the
tip
of the bill is used for biting off vegetation.
|
|
| Stout: the bill
is conspicuously high and wide, as in a grouse.
Use: mainly for picking seeds and
insects from the ground and biting tender shoots and buds from shrubs.
|
|
| Terete:the bill
is generally circular either in cross-section, or when viewed anteriorly,
as in a hummingbird.
Use: resemble straws,
used to sip nectar from flowers.
|
|
| Straight: the
line along which the mandibles close is in line with the axis of the head,
as in a bittern.
Use: stabbing prey
|
|
| Recurved: the
bill curves upward, as in a godwit.
Use: sifting shallow waters
|
|
| Decurved:the
bill curves downward, as in the Brown Creeper (Certhia americana),
or a curlew.
Use: for
probing in mud and sand for insects and worms.
The tip of the bill is very
sensitive so the bird can feel when it touches
its food. In some of these
birds the tip of the bill can open to grab the
food even when the rest of the bill stays shut.
|
|
| Bent: the bill
is deflected at an angle (usually deflected downward at the middle), as
in a flamingo.
Use: taking in
a mouthful of water, closing the bill, and
forcing the water out by pushing with their tongue. Small shrimps and other
animals are caught in the comb-like structures on the sides of the bill.
|
|
| Swollen: the
sides of the mandibles are convex, as in a tanager (Piranga).
Use: helps to cut tough food
|
|
| Acute: the bill
tapers to a sharp point, as in the Yellow Warbler (Dendroica petechia).
Use: probing for insects, picking or gleaning
insects off leaves, twigs, and bark.
|
|
| Chisel-like:the
tip of the bill is beveled, as in the Hairy Woodpecker (Picoides villosus).
Use: to make holes in trees, chisel
bark to reach insects
|
|
| Gibbous: the bill has a pronounced
hump, as in a scoter. |
|
| Spatulate, or spoon-shaped: the
bill is much widened, or depressed, towards its tip, as in the Norrthern
Shoveler (Anas clypeata).
Use: sifting through shallow waters
|
|
| Conical: the bill has the
shape of a cone, as in a redpoll. |
|
| With angulated commissure:
the commissure forms an angle at the point where the tomium proper meets
the rictus, as in a grosbeak, finch, sparrow, or bunting.
Use: for opening the hard outer shells
of seeds to reach the nutritious interior.
|
|
The Skimmer, has
probably
one of the strangest bills.
Use: They feed by flying just above
the surface of the
water with the open knife-like lower jaw
cutting through the water. When a fish is encountered
the jaw snaps shut.
|
|
| Edge Characteristic |
|
| Toothed:the upper
mandibular tomium has a "tooth," as in a falcon, or several "teeth," as
in a trogon.
Use: Added cutting power
|
|
| Serrate: the
bill has saw-like tomia, as in a merganser.
Use:adapted for grabbing and holding fish
|
|
| 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 a
thrush.
Use: grabbing and holding worms
|
|
| Lamellate, or sieve-billed:
the mandibles have just within their tomia a series of transverse
tooth-like ridges, as in swans, geese, and ducks.
Use: sifting through muck in search of
prey. Also, filtering out animal or plant material from the water. The combs
on the sides of the bill catch the food which is then removed with
the tongue and swallowed. The nail on the
tip
of the bill is used for biting off vegetation.
|
|
| Covering Characteristic |
The covering of the bill is
generally horny throughout and may be divided into distinct sections, as
in petrels and gannets. Sometimes, as in shorebirds, it is soft throughout.
The covering may show other modifications that constitute important characters. |
| Cere: the distal end of the
upper mandible may be horny, and the proximal portion may be thick and soft,
as in a hawk, pigeon, or parrot. |
|
| Nail: the tip of the upper
or of both mandibles may be conspicuously harder and set off in grooves,
as in ducks. |
|
| Other Characteristics |
|
| With gular sac:
the chin, gular region, and jugulum are distended. In the pelican
the gular sac is conspicuous, outwardly membranous, and featherless; in
the cormorant it is inconspicuous and partially feathered.
Use: scoop large mouthfuls of water and
fish
|
|
. There are about 190 species on the
list. In addition, you will be expected to learn the vocalization
for the 59 species labeled with a 
symbol. You can get extra credit for learning the vocalizations for the
22 species labeled 
A wing is broad when both the primaries and the secondaries are
very long throughout, as in the Great-horned owl.
