Foster is a forest ranger who'll come work in your town once it reaches the third star level rating. He is extremely shy around other Sims, but loves being around animals. He hopes for more animals to come in to the Forest.
In order to get your town up to the Star Level 4 rating, you have to make Superfeed for him to give to the animals. All you need is a fish (use one that is not worth much) and a flower from Ashley's flower store (don't buy a house plant, get a portable flower and don't get one that is expensive). Once you have those items go to Foster and choose the option of Superfeed. He'll make it and give it to you, then go to one of the animals and feed it to them. You will have to do it many times. If you feed an animal a few times it will appear outside your house. Foster also requires you to pull out the dead trees and replace them with other plants or trees to attract animals, you get five turns and Foster is happy. He may give you some more turns! He is rather nervous when talking to you but will get used to you when more animals come.
The Forest Ranger, who seems to love all types of animals. However, he does not appear to be very comfortable around other Sims, preferring animals over them.
The forest is a great place now! Foster is even trying to overcome his awkwardness with other Sims.