nest building is a kind of adaptation & adaptation has a positive impact on the survival of a species ->  nest building has a positive impact on the survival of a species  nest building has a positive impact on the survival of a species & a nest is a kind of resource for a bird ->  nest building has a positive impact on the survival of birds  young animals are born as a result of reproduction & a bird is a kind of animal ->  young birds are born as a result of reproduction  young birds are born as a result of reproduction & many birds reproduce during spring ->  many young birds are born during spring  many young birds are born during spring & birds build nests in the spring ->  birds build nests when many young birds are born  birds build nests when many young birds are born & a nest is used for protecting young by birds ->  birds build nests to protect young birds  nest building has a positive impact on the survival of birds & birds build nests to protect young birds -> nest building has a positive impact on the survival of birds by protecting young birds