Featured Science Paper
Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds
The study of hybridization in natural populations provides an opportunity to study the evolutionary processes involved in genetic divergence and the development of new species. This paper in PLoS ONE with a lead author who is an ex-Bird Island Field Assistant, uses data from a long-term demographic study to examine mixed-pairing and hybridization between two sibling species ‒ northern giant petrel and southern giant petrel.
The proportion of mixed-species pairs at Bird Island was always low, and showed no trend in the last 25 years. Some individuals in mixed-species pairs bred previously or subsequently with their own species, others subsequently with another partner also from the other species, and some mixed-species pairs remained together for multiple seasons. Mean laying date in mixed-species pairs was intermediate between northern and southern giant petrel (which typically lay six weeks apart). Although breeding success was relatively poor, some hybrid chicks have fledged (cf. mixed-species pairs at Marion and Macquarie islands, the few sites where they also occur, which always fail early). This includes one hybrid fledged in the early 1980s that has been breeding in the same area on Bird Island since the population study resumed in the early 2000s, and has fledged several chicks successfully.
Link to the full paper in the NERC Open Research Archive
Authors
Ruth M. Brown, N. M. S. Mareile Techow, Andrew G. Wood and Richard A. Phillips
Publication
PLOS ONE doi:10.1371/journal.pone.0121688
