Study

Recovery of the kakerori: an endangered forest bird of the Cook Islands

  • Published source details Robertson H.A., Hay J.R. & Saul E.K. (1994) Recovery of the kakerori: an endangered forest bird of the Cook Islands. Conservation Biology, 8, 1078-1086.

Actions

This study is summarised as evidence for the following.

Action Category

Control mammalian predators on islands for songbirds

Action Link
Bird Conservation

Physically protect nests with individual exclosures/barriers or provide shelters for chicks of songbirds

Action Link
Bird Conservation
  1. Control mammalian predators on islands for songbirds

    A paired before-and-after study in Totokoitu Valley, Rarotonga (6,700 ha), Cook Islands (Robertson et al. 1994), found that the nesting success of kakerori (Rarotonga flycatchers) Pomarea dimidiate was significantly higher in areas with an intensive black rat Rattus rattus poisoning programme (62% success for 71 nests in 1988-93), compared to the same areas in the 1987-8 breeding season (no nesting attempted) and to other areas without  a poisoning programme (26% success for 47 nests in 1987-93). In areas with rat control adult mortality also fell significantly, from 24% in 1989-90 to 6% in 1989-93. The population of kakerori increased from 29 birds in 1989 to 60 in 1993. This study also used nest guards, discussed in ‘Physically protect nests with individual exclosures/barriers’.

     

  2. Physically protect nests with individual exclosures/barriers or provide shelters for chicks of songbirds

    A before-and-after study on Rarotonga (6,700 ha), Cook Islands (Robertson et al. 1994) found that the nesting success of kakerori (Rarotonga flycatchers) Pomarea dimidiate was higher in 1990-92 when nests were protected with predator guards (30 cm aluminium bands around nesting trees to prevent introduced black rats Rattus rattus from climbing to the nests) than in 1987-89 when guards were not used. However this increase was not significant (nesting success of 36% for 48 nests in 1990-92 vs. 16% for 42 in 1987-89). This study also investigated the use of predator removal through poisoning, discussed in ‘Control mammalian predators on islands’. Using predator guards in predator removal areas did not appear to affect nest survival.

     

Output references
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