Generalist
or Specialist Discussion
Flying
Insect Eaters
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Black
Phoebe |
Whip-poor-will |
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|
Many
birds that catch insects on the wing have stiff narrow feathers
called rictal bristles that help them sense and/or
gather the insects into their mouths. Notice the rictal bristles
on both these birds. The Black Phoebe's beak is wide enough to snatch
at flying insects, but phoebes can eat insects on the ground or
in trees, or even some fruits. The whip-poor-will's beak is much
wider than the phoebe's, but is so soft and fragile that whip-poor-wills
can't pick up food that isn't in flight. So the Whip-poor-will is
more of a specialist. |
Seed
Eaters |
Crossbill |
Goldfinch |
|
|
Goldfinches
and crossbills both eat seeds. But goldfinches can eat many kinds
of weed seed, and also berries. Crossbill beaks are designed to
pry open the scales of cones from pines, spruces, or other evergreens.
But they're so good at that that they don't eat much else. So the
crossbill is more of a specialist. |
Nectar
Eaters |
Sicklebill
(hummingbird) |
Woodstar
(hummingbird) |
|
|
These
are both tropical hummingbirds. The woodstar can dip its beak into
many kinds of tropical flowers to feed. But the sicklebill is specially
adapted to feed on one common flower most hummers just can't get
their beaks into, the heliconia, which protects its nectar at the
bottom of a long, curved tube. So the sicklebill is more of a specialist.
|
Shorebirds |
Curlew |
Yellowlegs |
|
|
Curlew
beaks are designed to probe deep into holes to pull out burrowing
worms and other invertebrates. Yellowleg beaks can help them get
a much wider variety of food, but not those deep burrowers. So the
Curlew is more of a specialist. |
Fish
Eaters |
Merganser |
Pelican |
|
|
Mergansers
are ducks, and those serrations, nicknamed "teeth" along
the edge of their bill help them to catch more fish than most ducks.
That makes them more specialized than most ducks. But mergansers can
catch fish, insects, frogs, and many other little creatures in the
water. Pelicans have such a huge pouch and such a long beak that they
are only good for catching large fish, especially when the fish are
in groups called schools. So the pelican is more of a specialist than
the merganser. |
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2003 Journey North. All Rights Reserved.
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