Masked Booby (Sula dactylatra) Science Article 2
The breeding biology and reproductive output of a colony of Masked Boobies on Mutton Bird Point, Lord Howe Island, Australia, were studied during the 2001 02 breeding season. The colony produced a total of 200 clutches. Eggs were laid between 31 May and 15 September 2001, with 80% of clutches begun before 21 July. More than 90% of clutches consisted of two eggs, laid, on average, 5.3 days apart. Mean incubation period was 45 days.
David Priddel ET AL., Emu, 2005, 105, 105-113