What structural phase must a Baya Weaver nest reach before the male begins courtship displays?

Resembling a rough "pixie hat."

The construction timeline is intrinsically linked to the breeding cycle, where the partially finished nest serves as a crucial display model for attracting a mate. The male worker completes the primary structure, forming the hollow sphere, before moving into the courtship phase. At this stage, the nest lacks the final defensive entrance tunnel, causing it to temporarily resemble a rough shape often described as a "pixie hat." It is only in this configuration that the male initiates courtship, using specific calls and fluttering displays to attract the discerning female, who inspects the workmanship and structural soundness before granting approval for the final construction phases.