Describe or look at some different beaks and guess what they might be good at: ('Eyewitness BIRD' book has some excellent ideas) - eagles have strong curved pointy beaks for eating meat - finches have short stout beaks for cracking seeds - humming birds have long pointy beaks for getting nectar out of flowers - ducks have broad flat bills for eating water weeds
from:
http://www.minkhollow.ca/HatchingProgram/Ducks-Incubation/bed-qa.html
or this one:
Beaks or bills come in a multitude of shapes and sizes, varying as to how the bird must gather its food as well as to what food he eats. Think of the difference in the bill of a hummingbird versus that of a pelican. Let's explore these differences in the world of birds.
What exactly is a beak or bill? There is a core of bone of the upper and lower jaws, called mandibles. A horny layer of a material covers the bones. Both mandibles move in most birds, whereas in mammals only one jaw moves. Try opening and closing your mouth and see which jaw moves. Most birds move both.
Birds that eat seed, such as Northern Cardinals, have short strong bills that can crack open a hard-shelled seed easily.
Birds that eat flying insects have flat bills with a wide base so that they can catch a moving and small target, such as a gnat or fly.
from:
http://birding.about.com/od/birdanatomy/a/beaksandbills.htm
You could have done this research yourself. I'm about done doing everyone's homework for them.