Monitoring lizards on the Chickens

Forest and Bird, Issue 292, 1 May 1999, Page 9

Monitoring lizards on the Chickens

— from

DoC Northland.

Wanda

Vivequin,

etting rid of rats has been a boon for lizards on two of the Hen and Chickens Islands off Northland. A weeklong lizard monitoring programme this summer has shown some encouraging results. Both Lady Alice and Coppermine Islands, which form part of the northern Chickens group, are now rat free and monitoring the response of the lizards to these removals is now entering its sixth season. The islands are managed by the Department of Conservation’s Northland Conservancy, with one of the main objectives being to restore ecological communities and maintain a predator-free status. The reintroduction of some species of lizard, and monitoring the response of existing populations, are important parts of this programme. Much of the work on the Chickens is being guided by off-shore-island restoration ‘guru’ Dave Towns who works for

DoC Science and Research in Auckland. The lizard monitoring programme is managed by Whangarei-based conservation officer Richard Parrish. Pacific rats Rattus exulans were removed from Lady Alice Island in 1994 and from Coppermine in 1997. One beach site and two forest monitoring sites have been set up on each of the islands to measure the response of the lizards, with Coppermine being used as the control until the rats were removed. Species found on the islands include Duvaucel’s Gecko Hoplodactylus duvaucelii, moko skink Oligosoma moco, ornate skink Cyclodina ornata, shore skink Oligosoma smithi, Suter’s (or egg-laying) skink Oligosoma suteri, and the copper skink Cyclodina aenea. A number of lizards found on the Chickens Islands are no longer found on the mainland. While the lizard numbers will take some time to recover in the forests, DoC staff have been

encouraged by what is being caught on the beaches. During the December monitoring 27 lizards were caught on the beach on Lady Alice Island, the best result so far according to Richard Parrish. Several species of lizards have been re-introduced onto Lady Alice and Coppermine. The animals released to date include the Pacific gecko Hoplodactylus pacificus, Mokohinau skink or marbled skink Cyclodina ‘oliveri’, and McGregor’s skink Cyclodina macgregori. These have been taken from some of the smaller Chickens Islands and Sail Rock off the Hen (Taranga) where the species have managed to survive because these places have remained free of rats. The assumption behind these re-introductions is that these species would all have lived on the islands at some time in the past but disappeared as the result of the arrivals of humans and rats. The most recent re-introduc-tion took place in March 1998 when 30 Mokohinau skinks from

Muriwhenua Island and 39 McGregor’s skinks from Sail Rock were released into two separate areas on Lady Alice Island. Richard Parrish believes it’s particularly important to note that work on the islands is not just focusing on threatened species, but is also looking at the restoration of plant and animal

communities.