NEST Construction process . Intruders are chased off by one or both of mates. Method of construction. Bird excavates cavity by striking tree with bill and chipping away wood. Time of day.
Birds excavate at all times of day but more frequently in morning.
Length of time to build nest. Structure and composition matter . Variations in nest-cavity dimensions are given in Table 1. Maintenance or reuse of nests, alternate nests . Old nest cavities may be used as roost sites but are rarely used for nesting again.