What is the best way to get rid of pigeons that have roosted on a ledge outside the 4th floor of my building?
Answers:
You might want to consider a product that would prevent them from lodging there at all. There is a product (the link to a manufacturer is below-do a search for others) called a "bird spike". You can place these on ledges where pigeons roost and they will discourage the birds from landing and roosting on the ledge. As far as I know they do not harm the bird, they are just deterrents to them landing on the ledge. You may still have to contract with a company to install them if the ledge would be dangerous to access.
As far as hanging something, there are products out there like reflective strips, oversized owls, scary balloons, etc. that may scare birds but some birds learn quickly that the "scary" deterrent is artificial and not a true threat. Because of that they may eventually return.
Below are some links to suppliers of the "bird spikes" and the other birds deterrent items mentioned above.
Other answers:
AK-47
AK-47
if you can get to the ledge , try putting grease on it
bb-gun works well. Or airsoft gun if your sensitive to the birds feelings. It wont harm them, just scare them off. And it can be quite entertaining for guests to "try there luck"!
IF YOU CAN REACH WITH A WATER GUN USE SOME AMMONIA WATER. I HAVE DONE IT AND IT WORKS FINE, BUT THAT WAS A 2ND FLOOR HEIGHT. YOU MAY HAVE TO DO IT MORE THAN ONCE BEFORE THEY GET DISCOURAGED. I HAD TO DO IT TWICE.
its a long shot but mabey Cyote or wolf urine sprayed on the area might disourage them. You can get it at any outdoorsy store. Or try to get a recording of a hawk screching and play it really loud.( But if they are city birds they might not know what a hawk is).If you try the urine and it words you would have to reaply after it rains.