Mating system and genetic variation in the endangered New Zealand takahe
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The takahe (Porphyrio hochstetteri) is a highly endangered flightless rail that is endemic to New Zealand. Only one remnant population of takahe (120 adults) is left in the wild in Fiordland, which has been the source for introductions to four predator-free islands. The objective of the present study was to determine the mating system and amount of genetic variation in takahe using multilocus DNA profiling, in order to assist in the management of the island populations. There was no evidence of extra-pair paternity for the 27 (73%, n = 37) offspring to which paternity could be resolved. The paternity of the remaining 10 offspring could not be resolved due to low levels of minisatellite DNA variation, but in none was the resident male excluded. Overall, the DNA results along with behavioral and life history information indicate that extra-pair fertilizations should be rare or absent, and takahe join a small but growing list of long-lived species of birds that have been shown to exhibit genetic monogamy. In addition, the levels of minisatellite DNA variation detected in takahe are low relative to those reported for most other known outbred avian populations, and are consistent with the evidence of the takahe's persistence as a small, isolated population in Fiordland over at least the last 100 years. The low genetic variation is discussed in relation to possible evidence of environment depended inbreeding depression in translocated island populations of takahe.