I like birds, they're one of gods more picturesque creatures. Colorful cardinals, Musical Robins, Comical Crows. They keep the insect population in control, and lend a pleasant musical backdrop to spring and summer days. Birds quickly devour just about any insect pests in your garden, unfortunately they will also eat your garden.
When I see them picking my fruit and berry trees clean, decimating my grapes and feasting on my veggies... the friendship is over.
It would be easy to start picking them off as they enter my domain, but as I stated before, I like birds.. Besides the local authorities not to mention the ASPCA might have a thing or two to say about that.
There are dozens of products on the Market that promise to repel birds, most are basically modified scarecrows, such as many of the wind driven devices. They work some of the time. On a still day with no breeze or wind they're useless, that's when Heckle and Jeckle will have their field day. Moth balls are also said to repel many birds, but not all of them. Basically, You can repel some of the birds some of the time. All of the birds some of the time , but you can't repel all of the birds all of the time with the products mentioned above. They're helpful but not fool proof.
My experience has taught me that the best way to protect my harvest from birds is a combination of
1. Herbal deterrents
2. Bird netting that is properly installed
3. Predatory Decoys.
The Predatory Decoys, Owls and Hawks, are also beneficial in keeping rodents such as mice, moles and squirrels at bay.
In Tropical and semi-tropical regions the decoys are less effective particularly amongst non-migratory birds. Your best bet in such regions ,would be the rubber and inflatable snakes used in conjunction with netting where appropriate.
Bird netting so long as it properly placed is probably the most effective all-around control but is not always a feasible option.
Old VHS or Cassette tapes cut into strips and tied to bushes and branches will generally scare off many birds.
CDs or old tin can lids , Mylar or foil tape, or basically any reflective shiny material fluttering in the wind will scare off most birds.
* Spools of colored fine thread tossed across trees and shrubs is virtually invisible, and aggravates and deters many birds, however birds become entangled , and at times mangled.