| 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
|
|
. In addition, you will be expected to learn the vocalization for the species
labeled with a 
symbol. You can get extra credit for learning the vocalizations for the
species labeled 
