Deer!

If you see a very small deer, like the one here, in your garden or even walking down the street, it is probably not a baby, but an adult muntjac deer. Muntjac are quite common in Cambridge and, because they are so small, they can survive in habitats that wouldn't support larger grazing animals and they can get through quite tiny gaps. If a deer is actually on the road you can reduce the chance of it being hit by a car if you shoo it off to one side (although there is obviously a risk that you might be sending it off on the wrong side). As the deer are living and breeding in the city it's not desirable to consider catching them and moving them into the countryside.
(click the image to enlarge it)