Wing noises, wing slots, and aggression in New Zealand honeyeaters (Aves: Meliphagidae)

Two of New Zealand’s honeyeaters, the tui ( Prosthemadera novaeseelandiae ) and the bellbird ( Anthornis melanura ) can produce loud wing noises. In both species, modified primary feathers form slots in the wing that presumably make these noises. The slots of bellbirds are similar to those of hummingbirds (Trochilidae). Asymmetries in aggressiveness — as determined from inter‐ and intraspecific dominance — are closely related to the presence or size of the wing slots.