Postdoctoral fellows

Dr Ben Dilley


Dr Ben Dilley
PhD Conservation Biology (UCT)


Ben’s primary research field of interest is assessing and monitoring the impacts of introduced mice on seabirds breeding at oceanic islands. The fascination with remote islands started in 2009 when Ben overwintered on Marion Island which then led to a second year on Marion (2012-13), a year on Gough (2014-15), a summer on Tristan da Cunha, two summers on Nightingale (2015-17 working on Wilkins Buntings) and a summer on Inaccessible Island (2018). Ben enjoys projects where a conservation problem can be assessed and practical solutions implemented. To this end he is involved in a number of post-doc projects within Peter Ryan’s Seabirds and Islands Group.



Bester, M.N., Dilley, B.J., Davies, D. and Glass, T. 2020. Sub-Antarctic fur seals depredate northern rockhopper penguins at Nightingale Island. Tristan da Cunha. Polar Biology 1-3.

Dilley, B.J., Davies, D., Repetto, J., Swain, G. and Ryan, P.G. 2020. Rats and prions at Tristan da Cunha Island. Ostrich. In press

Dilley, B.J., Swain, G., Repetto, J. and Ryan, P.G. 2020. Using playback to estimate the distribution and density of the world's smallest flightless bird, the Inaccessible Island Rail Atlantisia rogersi. In press Bird Conservation International.

Dilley, B.J., Hedding, D.W., Schoombie, S. and Ryan, P.G. 2020. A survey of Great-winged Petrels Pterodroma macroptera breeding at sub-Antarctic Marion Island and a revised global population estimate. Ostrich

Carneiro, A.P., Pearmain, E.J., Oppel, S., Clay, T.A., Phillips, R.A., Bonnet‐Lebrun, A.S., Wanless, R.M., Abraham, E., Richard, Y., Rice, J., Davies, T.E., Dilley, B.J., et al., Handley, J. 2020. A framework for mapping the distribution of Southern Ocean seabirds across life-history stages, by integrating tracking, demography and phenology. Journal of Applied Ecology, 57 (3). 514-525.

Osborne, A., Jones, C.W., Risi, M.M., Green, D.B., Dilley, B.J., and Cooper, J. 2020. Cases of foreign egg adoption by Brown Skuas Stercorarius antarcticus on Marion and Gough Islands. Polar Biology

Requena, S., Oppel, S., Bond, A.L., Hall, J., Cleeland, J., Crawford, R.J.M., Davies, D., Dilley, B.J., et al., Ryan, P.G. 2020. Marine hotspots of activity inform protection of a threatened community of pelagic species in a large oceanic jurisdiction. Animal Conservation.

Ryan, P.G., Dilley, B.J., Davies, D., Glass, T. and Abadi, F. 2020. Short-term movement patterns, population estimates and breeding biology of an island endemic bird, the Tristan Thrush. Revista Brasileira de Ornitologia-Brazilian Journal of Ornithology, 27(4), pp.245-252.


Connan, M., Dilley, B.J., Whitehead, T.O., Davies, D., McQuaid, C.D. and Ryan, P.G. 2019. Multidimensional stable isotope analysis illuminates resource partitioning in a sub-Antarctic island bird community. Ecography 42, 1-2.

Dilley, B.J., Davies, D., Mitham, A., Glass, T., Repetto, J., Swain, G., and Ryan, P.G., 2019. Population estimates of burrow-nesting petrels breeding at the Nightingale island group, Tristan da Cunha archipelago. Marine Ornithology, 47 267-275

Dilley, B.J., Davies, D., Stevens, K., Schoombie, S., Schoombie, J., and Ryan, P.G. 2019. Burrow wars and sinister behaviour among burrow-nesting petrels at sub-Antarctic Marion Island. Ardea 107, 97-102.

Dilley, B.J., Hedding, D.W., Rexer-Huber, K., Parker, G.C., Schoombie, S. and Ryan, P.G., 2019. Clustered or dispersed: testing the effect of sampling strategy to census burrow-nesting petrels with varied distributions at sub-Antarctic Marion Island. Antarctic Science. 1-12.

Preston, G.R., Dilley, B.J., Cooper, J., et al. and Ryan, P.G., 2019. A plan of action to eradicate introduced house mice on South Africa’s sub-Antarctic Marion Island. In Veitch, D. (Ed.). Proceedings of the Third Island Invasives Conference, Dundee, July 2017. IUCN, Gland.

Ryan, P.G. and Dilley, B.J., 2019. Intertidal foraging by Tristan Thrushes. Ostrich 90(2): 179–181.

Ryan, P.G., Dilley, B.J. and Ronconi, R.A., 2019. Population trends of Spectacled Petrels Procellaria conspicillata and other seabirds at Inaccessible Island. Marine Ornithology, 47, pp.257-265.

Ryan, P.G., Dilley, B.J., Ronconi, R.A. and Connan, M., 2019. Rapid increase in Asian bottles in the South Atlantic Ocean indicates major debris inputs from ships. Proceedings of the National Academy of Sciences, 116(42), pp.20892-20897.


Brooke, M.d.L., Bonnaud, E., Dilley, B.J., Flint, E.N., Holmes, N.D., Jones, H.P., Provost, P., Rocamora, G., Ryan, P.G., Surman, C. and Buxton, R.T. 2018. Seabird population changes following mammal eradications on islands. Animal Conservation 21(1): 3-12.

Brooke, M.d.L., Bonnaud, E., Dilley, B.J., Flint, E.N., Holmes, N.D., Jones, H.P., Provost, P., Rocamora, G., Ryan, P.G., Surman, C. and Buxton, R.T. 2018. Enhancing the value of future island eradications needs improved understanding of past outcomes. Animal Conservation 21(1): 19-20. 

Dilley, B.J., Schoombie, S., Stevens, K.,Davies, D., Perold, V., Osborne, A., Schoombie, J., Brink, C.W., Carpenter-Kling, T. and Ryan, P.G. 2018. Mouse predation affects breeding success of burrow-nesting petrels at sub-Antarctic Marion Island. Antarctic Science, 30(2): 93-104.

Oppel, S., Bolton, M., Carneiro, A.P., Dias, M.P., Green, J.A., Masello, J.F., Phillips, R.A., Owen, E., Quillfeldt, P., Beard, A., Dilley, B.J., Davies, D. et al. 2018. Spatial scales of marine conservation management for breeding seabirds. Marine Policy, 98: 7-46.

Reisinger, R.R., Raymond, B., Hindell, M.A., Bester, M.N., Crawford, R.J., Davies, D., de Bruyn, P.N., Dilley, B.J., Kirkman, S.P., Makhado, A.B. and Ryan, P.G. 2018. Habitat modelling of tracking data from multiple marine predators identifies important areas in the Southern Indian Ocean. Diversity and Distributions, 24(4): 535-550.

Rollinson, D.P., Dilley, B.J., Davies, D. and Ryan, P.G. 2018. Year-round movements of white-chinned petrels from Marion Island, south-western Indian Ocean. Antarctic Science, 30(3): 183-195.

Schoombie, S., Dilley, B.J., Davies, D. and Ryan, P.G. 2018. The foraging range of Great Shearwaters Ardenna gravis breeding on Gough Island. Polar Biology, 41(12): 451-2458.

Schoombie, S., Schoombie, J., Oosthuizen, A., Suleman, E., Jones, M.G.W., Pretorius, L, Dilley, B.J. and Ryan, P.G. 2018. Avian pox in seabirds on Marion Island, southern Indian Ocean, Antarctic Science, 30(1): 3-12.


Dilley, B.J., Davies, D., Schramm, M., Connan, M. and Ryan, P.G. 2017. The distribution and abundance of Blue Petrels (Halobaena caerulea) breeding at subantarctic Marion Island. Emu, 117: 222-232.

Dilley, B.J., Schramm, M. and Ryan, P.G. 2017. Modest increases in densities of burrow-nesting petrels following the removal of cats (Felis catus) from Marion Island. Polar Biology 40: 625-637 

Jones, M.G.W., Dilley, B.J., Hagens, Q.A., Louw, H., Mertz, E.M., Visser, P. and Ryan, P.G. 2017. Wandering Albatross Diomedea exulans breeding phenology at Marion Island. Polar Biology 40: 1139-1148 

Schoombie, S., Dilley, B.J., Davies, D., Glass, T. and Ryan, P.G. 2017. The distribution of breeding Sooty Albatrosses from the three most important breeding sites: Gough, Tristan and the Prince Edward Islands. Emu 117: 160-169.


Dilley, B.J., Schoombie, S., Schoombie, J. and Ryan, P.G. 2016. Scalping’ of albatross fledglings by introduced mice spreads rapidly at Marion Island. Antarctic Science, 28(2): 73-80.

Pichegru, L., Edwards, T.B., Dilley, B.J., Flower, T.P. and Ryan, P.G. 2016. African Penguin tolerance to humans depends on historical exposure at colony level. Bird Conservation International, 26(3): 307-322.

Rollinson, D.P., Dilley, B.J., Davies, D. and Ryan, P.G. 2016. Diving behaviour of Grey Petrels and its relevance for mitigating long-line by-catch. Emu-Austral Ornithology, 116(4): 340-349.


Davies, D., Dilley, B., Bond, A., Cuthbert, R. and Ryan, P. 2015. Trends and tactics of mouse predation on Tristan Albatross Diomedea dabbenena chicks at Gough Island, South Atlantic Ocean. Avian Conservation and Ecology, 10(1): 5.

Dilley, B. and Davies, D. 2015. Mice massacre: help for Gough Island’s birds. African Birdlife, 4(1): 43-47.

Dilley, B.J., Davies, D., Bond, A.L. and Ryan, P.G. 2015. Effects of mouse predation on burrowing petrel chicks at Gough Island. Antarctic Science, 27(6): 543-553.

Ryan, P.G., Dilley, B.J., Jones, C. and Bond, A.L., 2015. Blue Petrels Halobaena caerulea discovered breeding on Gough Island. Ostrich, 86(1-2): 193-194. http://dx.doi.org10.2989/00306525.2015.1005558

Torres, L.G., Sutton, P.J., Thompson, D.R., Delord, K., Weimerskirch, H., Sagar, P.M., Sommer, E., Dilley, B.J., Ryan, P.G. and Phillips, R.A., 2015. Poor transferability of species distribution models for a pelagic predator, the grey petrel, indicates contrasting habitat preferences across ocean basins. PLoS One, 10(3): e0120014.


Jones, M.G.W., Dilley, B.J., Hagens, Q.A., Louw, H., Mertz, E.M., Visser, P. and Ryan, P.G. 2014. The effect of parental age, experience and historical reproductive success on wandering albatross Diomedea exulans chick growth and survival. Polar Biology, 37(11): 1633-1644.

Rollinson, D.P., Dilley, B.J. and Ryan, P.G. 2014. Diving behaviour of white-chinned petrels and its relevance for mitigating longline bycatch. Polar Biology, 37(9):1301-1308.

Ryan, P.G., Bourgeois, K., Dromzée, S. and Dilley, B.J. 2014. The occurrence of two bill morphs of prions Pachyptila vittata on Gough Island. Polar Biology, 37(5): 727-735.

Shaw, J.M., Dilley, B.J., Davies, D. and Ryan, P.G. 2014. Trapping and capture myopathy in Ludwig's Bustard. African Journal of Wildlife Research, 44(1): 16-23.


Dilley, B.J. 2013. Living on the edge: Sooty Albatross chick killed by a Northern Giant Petrel. Ornithological Observations 4: 138-142.

Dilley, B.J., Davies, D., Connan, M., Cooper, J., De Villiers, M., Swart, L., Vandenabeele, S., Ropert-Coudert, Y. and Ryan, P.G. 2013. Giant petrels as predators of albatross chicks. Polar Biology 36(5): 761-766.


Ryan, P.G., Dilley, B.J. and Jones, M.G.W. 2012. The distribution and abundance of white-chinned petrels Procellaria aequinoctialis breeding at the sub-Antarctic Prince Edward Islands. Polar Biology 35(12):.1851-1859.