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Canada Geese
The  Canada Goose used to be a concern for farmers during their seasonal migration as they would eat and trample crops.  Due to the recent changes in the climate, geese are not migrating as often, and are found taking up permanent residence in suburban areas.  While this is positive in that Canada Geese pose a large threat to air traffic safety, they can become aggressive towards humans and pets.  They are quickly becoming a persistent pest due to the fast rate of reproduction and the absence of natural enemies.

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Grackles & Blackbirds
Feces of these birds collects and damages roofs, gutters, drain spouts, and more in any place where they roost.  Their feces represents a health risk due to fungi and parasites which live in it.  These birds also produce a large amount of noise.

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Gulls
Similar problems are caused by gulls as those caused by grackles and blackbirds.  These problems are mostly confined to coastal areas.  They also pose a threat to air navigation, as many airports are located near bodies of water.

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Pigeons (Feral)
Pigeons are considered to be the number one bird pest.  Their feces has the same effects as that of grackles/blackbirds, and is corrosive.  These birds like to stay in whatever location they were born, and will eat nearly anything.  They cannot be trapped or relocated, as they are descended from homing pigeons.

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Starlings & Sparrows
These birds pose all of the same threats as pigeons, with one added danger, they are known to drive native bird populations to extinction.  Unlike pigeons, Starlings and Sparrows can be successfully trapped and relocated.

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Turkey Vultures
Turkey vultres pose the largest threat on rooftops, as they choose to use such areas to roost.  They can do a lot of damage to shingles and other roofing materials, gutters, etc.  A heavy duty electrical shock system is the best way to combat this pest.

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Woodpecker
The largest and only real problem caused by woodpeckers is that which they are named for.  They have been known to punch holes in fences, siding, decks, and other areas around the home/office.  Their infernal tapping on the side of your home can be a bothersome noise first thing in the morning.  Consider protective coatings designed to leave a foul taste in the bird's mouth as a deterrent.