Our planet is in the middle of a mass extinction event and many species are experiencing drastic reductions in population size. These population bottlenecks typically reduce genetic diversity and lead to increased inbreeding, driving species towards extinction. Unfortunately, New Zealand is an excellent place to study population bottlenecks and inbreeding, as so many of the country’s unique native species have been decimated by introduced mammalian predators and habitat loss.
My research explores the link between bottlenecks, inbreeding and reduced reproductive success in birds. We know inbreeding is linked to poor egg hatching success in many bird species, but it’s not known whether this is due to poor male fertility or other issues. To find out what's causing the problem, I am measuring bird sperm quality and relating it back to genetic diversity and inbreeding.
I have been collecting sperm samples from two native New Zealand bird species: South Island robins and hihi. I work on remote islands, but still need to measure sperm swimming speed in the field, so I've designed a mobile laboratory especially for this study. The mobile lab protects my gear from the elements and keeps the sperm at a constant temperature. Back at the university lab, I measure sperm length and check for abnormalities, and extract DNA from blood samples to assess genetic diversity and inbreeding in the males we’ve tested.
This research will help us understand whether bottlenecks and inbreeding lead to reduced male fertility in birds. My work also acts as a starting point to try and uncover precisely which genes might be being affected by inbreeding. The knowledge gained will improve management of threatened bird species in New Zealand and internationally.
This video was shot and edited by Regan Dodd. Thank you to the following people/organisations for lending their time/skills/footage/wide open spaces to help make this video: Kelly Meade, Judy Briggs, Steph Price, Robyn White, Jamie Ng, Natural History New Zealand, and Orokonui Ecosanctuary.
Funding for my research: University of Otago; Birds New Zealand