premise: young animals are born as a result of reproduction sent2: a bird is a kind of animal sent3: nest building is a kind of adaptation sent4: adaptation has a positive impact on the survival of a species sent5: many birds reproduce during spring sent6: a nest is a kind of resource for a bird sent7: birds build nests in the spring sent8: a nest is used for protecting young by birds.
hypothesis: nest building has a positive impact on the survival of birds by protecting young birds