Birds can be beneficial in a garden because they eat unwanted insects, but they can also be destructive. Birds eat newly planted seeds before they have a chance to grow, and they peck at leaves and fruits or pull up small seedlings. Fortunately, birds are relatively easy to frighten, so it's possible to deter birds humanely until your plants are well-established enough to live with them.
Start seeds indoors in pots whenever possible. Some seeds, like beans and pears, do better when sown directly into the garden, but giving your other seeds a chance to grow a few inches tall in a protected location will make them better able to stand up to bird attacks and give you more successful plants.
Consider covering large plantings with floating row covers. These thin cloth covers protect seeds and seedlings from birds while warming the soil and letting light through. Leave the covers on until the seedlings are 3 or 4 inches tall.
Scare the birds with shiny things. Old CDs or broken mirrors hung from trees make birds nervous because they flicker and throw unexpected shadows. For potted plants, make small flags by taping strips of tinfoil to toothpicks and placing the toothpicks in the soil. When the tinfoil moves in the wind, it will frighten the birds.
Set up some Mylar flash tape to keep birds out of your strawberry plants. Place the tape along the edge of the row and secure it with stakes. Make sure the tape doesn't break, and replace it regularly as the shiny surface fades.
Protect berry bushes by covering them with bird netting. Make sure the stakes are taller than the bushes so the birds can't sit on the net and reach the fruit.
Try some commercial bird deterrents. These include decoy predators like snakes and owls, or electronic noisemakers that click or make hawk noises. For these to be most effective, try a few different ones and move them around at random intervals, or the birds will just get used to them and ignore them.