Spray the hammock with a chemical chewing deterrent designed for birds like Ro-Pel or Bitter Apple. Deterrents designed specifically for mammals will not usually work on birds. Tobacco sauce and hot peppers do not work either.
Set up an animated scarecrow that looks like an owl or hawk. According to a 1992 study by the University of California, the best scarecrows are lifelike and move. Models of snakes and unanimated owl models had little effect on birds.
Tie aluminum pie pans, strips of mylar reflective tape or old CDs on or near your hammock. Objects that move and reflect light tend work well, especially when they are moved around frequently. Change items around every day or two to keep birds from getting used to them.
Play bird alarm and distress calls near the hammock. Special audio bird deterrents can be purchased with calls programmed in. These devices usually cost several hundred dollars and only need to be played during daylight hours.
Use a marker to draw large eyes on a mylar balloon. Tie the balloon to the hammock so it blows in the wind. Move the balloon to different areas every day or two.
Hang wind chimes near the hammock. The movement and sound of wind chimes may be enough to keep birds away.
Move any bird feeders and birdbaths to another area of your yard. Attract birds to areas away from your hammock.
Place an alternative nesting material nearby for birds to use instead of your hammock. Nesting material appropriate for wild birds can be purchased online or at a garden center.
Hang up the hammock when you're not using it. Hanging a hammock on a large hook helps it stay cleaner, last longer and ensures it is ready to use when you want it.