Effects of supplementary feeding and artificial twinning on nestling growth and survival in Australasian gannets (Morus serrator)

Published source details Bunce A. (2001) Effects of supplementary feeding and artificial twinning on nestling growth and survival in Australasian gannets (Morus serrator). Emu, 101, 157-162.
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This study is summarised as evidence for the following.

	Action	Category
	Provide supplementary food for gannets and boobies to increase reproductive success Action Link
	Foster eggs or chicks of gannets and boobies with wild conspecifics Action Link

Provide supplementary food for gannets and boobies to increase reproductive success

A small controlled study at a marine reserve in Queensland, Australia, in the breeding seasons of 1997-8 and 1998-9 (Bunce 2001) found that Australasian gannet Morus serrator chicks were reached significantly heavier weights in 1997-8 when they were fed every 2-3 days (starting at five days old and continuing until 40 days old) with approximately 5% of their bodyweight in pilchards Sardinops sagax, compared to control (unfed) chicks, however there were differences in weight in 1998-9 were not significant, although trends were in the same direction (1997-8: maximum weight of approximately 3900 g for fed chicks, n = 4 vs. approximately 3250 g for controls, n = 8). Over both years fledging success was higher for fed nests, but this was not significant (100% fledging success for fed nests vs. 90% for controls). This study also investigated the impact of adding foster chicks to gannet nests (see ‘Foster eggs or chicks with wild conspecifics’).
Foster eggs or chicks of gannets and boobies with wild conspecifics

A small controlled study at a marine reserve in Queensland, Australia, in the breeding seasons of 1997-8 and 1998-9 (Bunce 2001) found that Australasian gannet chicks Morus serrator were significantly lighter, and hatching and fledging success significantly lower in nests where a second egg or chick was added to the nest (‘experimental nests’), compared to control nests (maximum weight of approximately 2500 g for experimental nests in 1997-8, n = 4 vs. approximately 3250 g for controls, n = 8; data not provided for 1998-9; 1997-9: hatching success of35% for experimental nests vs. 70% for controls; fledging success of 63% for experimental nests vs. 90% for control). Over both years, the number of chicks fledged by experimental nests was higher than control nests, but this was not significant (1.3 chicks/nest for experimental nests, n = 8 vs. 0.9 chicks/nest for controls, n = 8). This study also investigated the impact of supplementary feeding on gannet chicks (see ‘Provide supplementary food to increase reproductive success’).