Drawing birds like Audubon is very demanding and difficult. Although his designs were better than the art that as an objective science, they really did resemble birds, he claims to represent. We can also make drawing like him with only lot of practice and by joining any good traditional art school for some years.
But if you want to make simple sketches of birds then simply apply pencil on paper and begin to make some shapes. When something like this could be a bird, put in one eye and a beak, topknot and it would be acceptable, maybe even fun.
Almost all kind of shapes can be made to look like birds. You can made birds sketch with combination's of squares, circles, triangles, rectangles, polygons etc. You can draw picture of any bird and add an eye, a few feathers, a beak, maybe a tail, and draw the image of a bird. You can take a picture of a piece of fruit, guitar, pot, box, bag, and add features in birds and there you are.
You can also create a whole story represented with bird’s sketches.
Pencil Drawing Art