Answer the following question given this paragraph: 

The size and shape of the beak is related to the food the bird eats and can vary greatly among different birds. Parrots have down-curved, hooked bills, which are well-adapted for cracking seeds and nuts ( Figure below ). Hummingbirds, on the other hand, have long, thin, pointed bills, which are adapted for getting the nectar out of flowers ( Figure below ). Hawks, eagles, falcons and owls have a sharp, hooked beak.


Q: What characteristic of birds is related to the food they eat?


A:
beak