Other

Crows (black birds) have been eating rotten flesh from dead zombies and dead people. They have grown accustomed to it and if they find living people they will flock around them hoping for the zombies to show up and have a showdown. Sometimes the crows will start screeching so nearby zombies appear. This starts happening in season 4. Crows start developing red eyes like the dead. Crows can usually be seen lingering around dead bodies and the dead.
Rats - There are a lot of rats feasting on dead bodies. They are very common in the cities and sewers. The rats have gained red eyes as well, due to them eating so many dead bodies. Rats are scared of the zombies because the zombies will eat them if they can get their hands on them. Rats are able to differentiate the living from the dead due to smell and mannerisms. If you see Rats running away from an area its a good bet that there are zombies in that direction. These Rats eat so much flesh from the dead bodies that they are starting to grow unusally big, there will be showings of big rats the size of smaller dogs. But luckly they still don't become aggressive towards people. Due to the Rats flesh eating diet it is highly not recommended to decide to kill and eat them, but they can be useful for traps or decoys for the dead. Due to the Savage Curse the Savages are able to eat the Rats and they tend to do so a lot.