Interactions between nesting birds and invertebrates are a common, yet poorly understood ecological phenomenon. Many of these types of interactions are close and prolonged, and therefore potentially critical to one or both of the species involved in the interaction. However it is unusual for the nature of the interaction to be evaluated in a manner that reveals the impact of the relationship on both parties to the interaction. This study examines two relationships between nesting birds and invertebrates, both of which involve the hooded parrot (Psephotus dissimilis), a small grass parrot that inhabits the tropical savannas of northern Australia. ¶ The field-work for this project was conducted over two parrot breeding seasons in 2006 and 2007 near Katherine, Northern Territory, in the Australian dry tropics. ...