Complex sentence: The males build a nest for the eggs by digging a large pit in winter and filling it with leaves and grass over the nest four months, where the female lays one egg per day for several days in the spring.
Split into simpler sentences: The males build a nest for the eggs by digging a large pit in winter and filling it with leaves and grass over the next four months. The female lays one egg per day for several days in the spring.