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be presented in a particular way. As such the simpler, modular enclosure designs which can easily be adapted are favoured at the university. Multiple huts with nest boxes are available to the birds within each area. These provide kea personnel with an opportunity to monitor impending breeding activity. Each compartment has a ‘frame’ of soft willow branches, replaced annually, for perching along their periphery. There is no furniture below the perches leaving ‘enrichment islands’ of 6 x 6m in the centre of the main enclosures. Enrichment plays a big part in the lives of Vienna’s kea and includes a variety of substrate types, introduced vegetation (fresh and dry), a planted plot of root vegetables for the birds to dig up, and a large number of enrichment items they can deconstruct including cardboard boxes, coconuts with holes drilled into them, cut or whole fruit in ice blocks etc. During summer, fresh trees are cut and parts of the roof are covered with reed mats to help keep the enclosure cool while a fog machine is used to reduce temperature on calm days. Xmas trees are also collected after the festive season and installed as a small forest in the main enclosure. Problem solving items are reserved for the more controlled behavioural studies which take place in the experimental enclosures on a regular basis. Kea involved in these studies are separated for no longer than 20 minutes at a time and are released back into the group when they stop exploring an apparatus for more than 2 minutes. As soon as females or pairs choose a nesting area, they are separated off for the duration of the breeding season before aggression is demonstrated. Even though females of the same clutch may spend considerable time in preening each other prior to the breeding season, as soon as breeding behaviour is observed the females will not allow other females close to their breeding compartment (although a few males may be tolerated).
So how is female aggression recognised at the Vienna facility? Females will often displace (the act of causing another kea to move away through use of threatening behaviour toward that individual) both males and females equally; however in contrast to males they will aim to bite the females rather than just displace. On a few occasions it has been observed that a female will not stop her attack, even when it is clear the other female is subordinate (the Vienna team has also observed this behaviour within macaque troops). In saying this, Vienna has never had any injuries sustained by their females, no doubt due to the fact that the birds are well monitored, have room to move away from each other, have access to multiple shelter areas which act as sight barriers between females, and breeding pairs are removed from the group as soon as it is clear they are nesting. So why have female aggression incidents resulted in death here in NZ? In the past, enclosure sizes have been significantly smaller and sight barriers often nonexistent, resulting in birds not being able to move away or hide from more dominant females or pairs. In addition to this, breeding females have not been removed to other enclosures but are often ‘managed’ by attempting to prevent nesting behaviour altogether; removing the opportunity for nest building and/or removing eggs. Most likely this would only serve to frustrate paired females, increasing stress, and potentially leading to increased incidence of aggression toward other females in the same enclosure. In some facilities female kea have been held together in single sex groups to prevent breeding behaviour altogether. Although these facilities have not recorded any deaths, they have recorded the highest levels of stereotypic behaviour of any observed facilities, indicating that this is unlikely to be an appropriate best practice management option. 7