granted, i live in the country, so i would fix the problem with one round of 12ga 2 3/4inch number 7 birdshot, but for you city dwellers, i got a solution that works.....dont laugh.... i swear on my GT this works...
1. go to walmart in the toys section. you know those little plastic/rubber snakes that you can buy for $1.00 or so that look semi-real? get 3 or 4 of them.
2. place them in various places in the rafters of your carport with thier heads facing down so the bird will see them.
3. since snakes are a birds natural predator... the bird will NOT hang out underneath your carport. it will find sanction somewhere else. birds are prey animals, they wont take the time to find out if the snakes are real, they will scram.
4. if it does keep coming back, reposition the snakes in a different location. if the bird frequents one area, put a snake right in that spot.
5. you could try laying one on your car if all else fails. but i know plenty of people who have ridded themselves of birds in this way.
6. if the bird is stubborn or just plain stupid, check your citys ordinance on discharging firearms
hope this solves your problem.