I read it as a paperback book somewhere in the mid-90s, I think. The protagonist lived in an apartment building. He's out on the balcony when a birdlike (but humanoid) alien swooped down and attacked him. The presence of the aliens was commonly known and was a known danger. He kills it with his watering can and is rewarded by either the aliens or the humans for it with money. Other than that, all I remember was that the chapters were started with an internet-like news report which I think chronicled things getting worse and more violent. One of the updates involved the bombing of a bridge with the casualties raised by having two slow-moving trucks moving side by side obstructing traffic and ensuring a full bridge.
The internet system was pretty ubiquitous as I recall. I think that he looked up his watering can shortly after the incident with the aliens, but decided to keep this one, even if it leaks a bit. I want to say that it was by Piers Anthony, but none of the book titles look familiar. I think the cover I had showed the man being attacked by the bird-man, which looked kind of like the illustrations on the cover of The Stand.