Migration strategies and breeding biology of 

the Fluttering Shearwater

The Fluttering Shearwater is a seabird only found breeding in New Zealand. Although one of New Zealand’s most common seabirds, pretty much nothing was known about it up until this study. This is the first study to examine the breeding biology, migration, foraging ecology and diet of this species. Fieldwork was carried out on Burgess Island, in the Hauraki Gulf, from September 2015 to January 2016. This study paves the way for further investigations into the ecology of this species as well as to facilitate for future conservation efforts such as the establishment of successful translocations. 


  •  ​Berg, M., Linnebjerg, J. F., Ismar, S., Taylor, G., Gaskin C., Åkesson, S., & Rayner, M. Year-round distribution, activity patterns and habitat use of a poorly studied pelagic seabird, the fluttering shearwater (Puffinus gavia). 2019. PlosOne.                                                                                                                                                                    

  • Berg, M., Linnebjerg, J. F., Ismar, S. M., Gaskin, C. P., & Rayner, M. J. (2017). Breeding biology of fluttering shearwaters (Puffinus gavia) on Burgess Island in Northern New Zealand. Emu-Austral Ornithology, 1-10.​​​​

Berg et al. 2019

Berg et al. 2017

Tropical bird conservation in Bolivia



With an estimated number of over 1,000 bird species, Madidi National Park is one of the most species-rich areas on the planet by holding approximately 10% of the world’s bird species.  The exceptional biodiversity and a high number of endemic and threatened, and range-restricted species of both plants and vertebrates have classified the area as a  “Biodiversity Hotspot” with a high conservation priority.  During one year I surveyed remote areas of the Madidi National Park for rare and engendered bird species restricted to the foothills of the Andes. These studies were sponsored by Asociación Armonía and resulted in the discovery of a new population of the green-capped tanager, which was previously thought to be endemic to Peru.  I also undertook conservation assessments and assisted with establishing an Ecolodge in Serranía Sadiri.




  • Berg, M. & Hennessey, B. 2019. An avifaunal survey and conservation assessment of Serranía Sadiri, Madidi National Park, Bolivia. Cotinga, 41:57-71.

  • Berg, M., Kleunen, A. & Hennessey, B. 2013. Range and status of the Green-capped Tanager Tangara meyderdeschauenseeiin in Bolivia. Cotinga, 36; 52-55.   

Berg and Hennessey, 2019

Berg et al. 2013

Uncover the breeding ground of the endangered New Zealand storm petrel


We designed and conducted an integrative radiotelemetry approach to uncover the breeding grounds of the critically endangered New Zealand Storm Petrel, a species considered extinct before its rediscovery in 2003. Solar-powered automated radio receivers and hand-held telemetry were used to detect the presence of birds on three island groups in the Hauraki Gulf near Auckland, New Zealand. In total, four New Zealand Storm petrel breeding burrows were detected and two NZSP chicks were ringed. Our study suggests an avenue for other breeding ground searches in one of the most threatened avian Orders and highlights the general need for information on the location of breeding sites and understanding the breeding biology in data-deficient birds.



  • Rayner, M. J, Gaskin, C.P., Fitzgerald, N.B., Baird, K.A., Berg, M., Boyle, D., Joyce, L., Landers, T.J., Loh, G., Maturin, S., Perrimen, L., Scofield, R.P., Simm, J., Southy, I., Taylor, G.A. Tennyson, A.J.D., Robertson, B.C., Young, M., Walle, R., and Ismar, S.M.H.2015. Using miniaturized radiotelemetry to discover the breeding grounds of the endangered New Zealand Storm Petrel Fregetta maoriana. Ibis, 157(4), pp. 754-766.



Rayner et al. 2015