they eat dead humans
Some of them are Fringillidae, Sparrows, Finches, Cardinals, and Grosbeaks.
Seed eaters tend to have short, robust beaks. Sparrows, finches, parrots, are just three examples.
by seeing
Beaks help birds hatch out of their eggs and get their food.
to find food or make shelter! errbody knows that!
Ducks have beaks, because the use their beaks to find and eat food.
Toco toucans get there food by flying up to a tree and picking off the food with there colrful beaks.
If their beaks are down in the seeds when they shake their heads, as I suspect you mean, they are trying to uncover their favorite seeds. House Sparrows, for example, are very fond of millet, so when they've eaten all the millet seeds they can see, they move the seeds around to find some more millet.
they eat rice
The flamingo has a curved beak to help with food and filtering. They are able to scoop up food with their curved beaks.
With their beaks....