The ex-situ nutritional management of two critically endangered Australian bird species

Abstract

As zoo-managed wildlife populations are increasingly relied upon to bolster the long-term survival of many species in the wild it is more vital than ever to investigate the nutritional requirements of threatened wildlife species. In this thesis, I explored the nutritional management of two critically endangered Australian bird species, the regent honeyeater (Anthochaera phrygia) and the plainswanderer (Pedionomus torquatus). For both species, I conducted nutritional studies to investigate the role of diet in health parameters critical to each species and assess the faecal microbiomes to investigate relationships with dietary intake and individual traits. Plains-wanderers have historically suffered from vitamin E deficiency and high total cholesterol. Diet intake trials showed that plainswanderers that consumed higher amounts of lipid had significantly lower circulating α-tocopherol levels than birds that consumed lower amounts of dietary lipid. Ensuring that the feathers of zoo-bred regent honeyeaters are equivalent yellowness to their wild counterparts is hypothesised to aid in pairing and breeding success of the birds when released to the wild. The feather yellowness of captive birds and wild regent honeyeater museum skins was equivalent. Connection of feather yellowness to bird health status was inconclusive and the challenges encountered with this dataset highlight the obstacles when working with endangered wildlife species. In this thesis I also present the first characterisation of the gut microbiome of both the plains-wanderer and regent honeyeater. I used functional analysis to link presence of microbial taxa to nutrition, making inferences regarding wild diet and bird health to inform management decisions.