Individual study: Use of tape-recordings to attract dark-rumped petrels Pterodroma phaeopygia to artificial nesting burrows on Santa Cruz Island, Galápagos, Ecuador
Cruz J.B. & Cruz F. (1996) Conservation of the dark-rumped petrel Pterodroma phaeopygia of the Galápagos Islands, 1982-1991. Bird Conservation International, 6
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Control mammalian predators on islands for seabirds
Two before-and-after studies on two Galápagos Islands, Ecuador (Cruz & Cruz 1996), found that dark-rumped petrel Pterodroma phaeopygia fledging success increased (on Floreana Island, 173 km2) and predation of adults decreased (on Santiago Island, 585 km2) following black rat Rattus rattus and feral animal control. On Floreana, fledging success increased (and nestling predation decreased) from 31% in 1981-2 to 46% (1983) and 72% (1984) with control in 1983-4. It declined in 1985 (to 23%) with increased feral cat Felis catus predation of young but increased again following cat control to 70-80% in 1986-8. Between 83 and 104 nests were studied each year. On Santiago, 55% of 510 monitored adult petrels were predated in 1985, but only six were in 1986, following an 80% reduction in the feral pig Sus scrofa population. Rats were intensively controlled by poisoning with coumatetralyl, whilst pigs, cats, goats Capra hircus and donkeys Equus asnus were shot. This study is also discussed in ‘Provide artificial nesting sites’ and ‘Use vocalisations to attract birds to safe areas’.
Use vocalisations to attract birds to safe areas
A before-and-after study on two islands in the Galapagos, Ecuador (Cruz & Cruz 1996), found that playing dark-rumped petrel Pterodroma phaeopygia phaeopygia vocalisations from loudspeakers in 1988-90 successfully attracted petrels to an area on Santa Cruz Island provided with artificial burrows, but that playing similar recordings on the predator-free island of Pinta failed to attract any petrels in 1991. The role of artificial burrows in this study is discussed in ‘Provide artificial nesting sites’, and predator control in ‘Control mammalian predators on islands’.
Provide artificial nesting sites for burrow-nesting seabirds
A replicated study on Santa Cruz in the Galápagos Islands, Ecuador (Cruz & Cruz 1996), found that the use of artificial burrows by dark-rumped petrels Pterodroma phaeopygia phaeopygia increased each year from 1988-90, although only one chick was fledged from the burrows. In 1988, 68% of the eighty burrows were prospected by petrels, although none nested. In 1989, 39 petrels staying in burrows overnight and in 1990, four pairs laid eggs in burrows. However, three of the four chicks produced were predated, probably by rats. Petrel vocalisations were played at the nest site each night, with the results discussed in ‘Use vocalisations to attract birds to safe areas’. Predator control on the Galápagos Islands is discussed in ‘Control mammalian predators on islands’.