Making a scarecrow head is a really cheap, really fun way to spend an autumn day. Here's how I made this "Croweater" fellow above. I used the same technique to make this "Skater Punk" (with a mohawk and safety pin in his eyebrow) scarecrow too.
Simple components: Stryofoam head, straight pins, burlap (a yard will do), Elmer's glue, paint brush, paints (black, rust, straw color).
Begin with what you need - styrofoam head (see link above and also Michael's store is carrying them), Elmer's glue, paint brush, black acrylic paint, straw colored acrylic paint, rust acrylic paint, and a yard of burlap.
Carve out eye sockets to be big holes. Carve out mouth so it's a grimacing hole. Carve out cheekbone slashes like skeleton look.
Mix 2 parts glue to 1 part water. Cut burlap into uneven pieces. Fray the edges by pulling on them and letting strings unravel. Dip into the glue/water mix, wring it out and place around the head. Use straight pins to pin it down on curves so it sticks. In a few hours it will dry hard.
Now, take black paint and thin out with some water - about 2 parts black paint to one part water. Dip brush into it, now push brush into the pores of the burlap so the black goes into the holes. Take a baby wipe and immediately wipe the surface of the fibers off so they aren't really black.
Once you've done the whole thing like this, leave the recessed cracks and crevices blackish, but take the straw paint on the brush and wipe some off so it's not too gooey, just kinda dry brush. Brush over the top of burlap lightly to bring back the burlap color. Don't worry about doing this evenly. Make it staggered in color intensity. Leave deep areas like sockets, cheekbones and under hood dark.
The last touches are to take some rust paint and mix with water like you did with the black paint. Drag the brush from top of forehead down eye area, cheek, to chin like water drips. Brush a bit here and there randomly all over to add some weathering.
I added a fake crow pinned to the top with a hair pin and then put some feathers in the scarecrow's mouth protruding in all directions as if he ate a bird.
Here's my video to learn it -