If there is a dead bird on a public sidewalk, what agency should be informed to dispose of the remains?

Try your local animal control agency.

Call 911 give adress and they will contact dispacth to animial control.

They do have Pitt bull mixed dogs but they are so sweet. I honestly believe it is about how they are loved and cared for makes all the difference.

And what happens when they are closed?

Try the county Animal Control