this describes both the animal's job and the part of the environment that it uses (the area and the time when the animal is active). So, for example, bats and chimney swifts have the same specialized job: insect-eaters that feed on the wing. They may even sleep in the same chimney, but bats are active at night, while chimney swifts are active during the day. (A lucky person may be able to watch at dusk as the birds, having completed the day shift, return to the chimney, and the bats, working the graveyard shift, leave it.) They occupy similar, but not exactly the same, niche.