Doctor Chris Todd


Graduated PhD 2020

Thesis Title

The ecology and conservation of the Christmas Island flying-fox (Pteropus natalis)

Research Project

Holding Image - MaleThe Christmas Island flying-fox (CIFF) is the last remaining indigenous mammal on Christmas Island, a remote, beautiful, and ecologically unique part of Australia. However, Christmas Island's biodiversity is under threat from anthropogenic change. This is evidenced by the extinction of two native rat species, and the only two mammal extinctions in Australia in the last 50 years: the Christmas Island shrew (Crocidura trichura), and the Christmas Island pipistrelle bat (Pipistrellus murrayi). In addition, there have been significant population declines in most endemic birds, and all but one endemic reptile have been lost from the wild.

The CIFF was listed in January 2014 as Critically Endangered under the Commonwealth Environment Protection and Biodiversity Conservation (EPBC) Act 1999.  Since 1984, the population has declined by 67% and if the causes of decline are not identified and remedied, it too will become extinct. The precipitous decline of the CIFF has serious implications for Christmas Island's endemic flora and fauna as its role in seed dispersal and pollination is critical for maintaining the health of the island's unique ecosystems. The CIFF's decline is paralleled by that of other fauna on the island, pointing to an unidentified but widespread malaise within Christmas Island's ecosystems.

Understanding the CIFF's decline and designing appropriate management interventions requires an understanding of the species' autoecology. However, as is the case for many flying-fox species, information on basic life history parameters, population structure, social organisation, and habitat use is lacking for the CIFF.

My PhD research is aims to address these important information gaps in the flying-fox's ecology with a special focus on: i) developing methodologies to accurately estimate the population size and trends with defined confidence; ii) identifying important life history events, including the timing of reproduction and mating, reproductive success, and growth and survival rates; and iii) determining the spatiotemporal patterns of foraging and roosting across the landscape of Christmas Island. Ultimately, I hope that the framework of my research will serve as a model for conservation and management efforts for other declining flying-foxes species as well other declining species populations on Christmas Island, and systems within Australia and beyond.

Media Coverage

Going Batty (opens in a new window)
Scientists scramble to save Christmas Island's last endemic mammal, the Christmas Island flying fox (opens in a new window)
A Science Story: Saving Christmas (opens in a new window)
Monitoring Christmas Island's Endangered flying fox population (opens in a new window)

Research Supervisors

Dr Justin Welbergen, Dr David Westcott, Dr John Martin, Dr Karrie Rose


Book Chapter

Villalobos-Chaves D, Bonaccorso FJ, Rodríguez-Herrera B, Cordero-Schmidt E, Arias-Aguilar A, Todd CM, (2016) 'The influence of sex and reproductive status on foraging behavior and seed dispersal by Uroderma convexum (Chiroptera: Phyllostomidae)', In Sociality in Bats (pp. 281-301). Springer International Publishing.


Lloyd-Jones LR, Bravington MV, Armstrong KN, Lawrence E, Feutry P, Todd CM, Dorrestein A, Welbergen JA, Martin JM, Rose K, Hall J, Phalen DN, Peters I, Baylis SM, Macgregor NA, Westcott DA, (2023) 'Close-kin mark-recapture informs critically endangered terrestrial mammal status', Scientific Reports, vol.13, no.1, Article no.12512

Todd CM, Westcott DA, Martin JM, Rose K, McKeown A, Hall J, Welbergen JA, (2022) 'Body-size dependent foraging strategies in the Christmas Island flying-fox: implications for seed and pollen dispersal within a threatened island ecosystem', Movement Ecology, vol.10, no.1, Article no.19

Nesi N, Tsagkogeorga G, Tsang SM, Nicolas V, Lalis A, Scanlon AT, Riesle-Sbarbaro SA, Wiantoro S, Hitch AT, Juste J, Pinzari CA, Bonaccorso FJ, Todd CM, Lim BK, Simmons NB, McGowen MR, Rossiter SJ, (2021) 'Interrogating Phylogenetic Discordance Resolves Deep Splits in the Rapid Radiation of Old World Fruit Bats (Chiroptera: Pteropodidae)', Systematic Biology, vol.70, no.6, pp 1077-1089

Dorrestein A, Todd CM, Westcott DA, Martin JM, Welbergen JA, (2019) 'Impacts of an invasive ant species on roosting behavior of an island endemic flying-fox', Biotropica, vol.51, no.1, pp 75-83

Todd CM, Westcott DA, Rose K, Martin JM, Welbergen JA, (2018) 'Slow growth and delayed maturation in a Critically Endangered insular flying fox (Pteropus natalis)', Journal of Mammalogy, vol.99, no.6, pp 1510-1521

Bonaccorso FJ, Todd CM, Miles AC, Gorresen PM, (2015) 'Foraging range movements of the endangered Hawaiian hoary bat, Lasiurus cinereus semotus (Chiroptera: Vespertilionidae)', Journal of Mammalogy, vol.96, no.1, pp 64-71

Gorresen PM, Cryan PM, Dalton DC, Wolf S, Johnson JA, Todd CM, Bonaccorso FJ, (2015) 'Dim ultraviolet light as a means of deterring activity by the Hawaiian hoary bat Lasiurus cinereus semotus', Endangered Species Research, vol.28, no.3, pp 249-257

Bonaccorso FJ, Winkelmann JR, Todd CM, Miles AC, (2014) 'Foraging movements of epauletted fruit bats (Pteropodidae) in relation to the distribution of sycamore figs (Moraceae) in Kruger National Park, South Africa', Acta Chiropterologica, vol.16, no.1, pp 41-52

Todd CM, (2012) 'Effects of prey abundance on seasonal movements of the Hawaiian hoary bat (Lasiurus cinereus semotus) (Masters dissertation, University of Hawai'i at Hilo).

Gorresen PM, Miles AC, Todd CM, Bonaccorso FJ, Weller TJ, (2008) 'Assessing bat detectability and occupancy with multiple automated echolocation detectors', Journal of Mammalogy, vol.89, no.1, pp 11-17