Abstract
The breeding cycle of the Red-tailed Tropicbird (Phaethon rubricauda) on Green Island, Kure Atoll, Hawaiian Islands, was studied during 1964 and 1965. Study methods included direct observation of marked nests and of leg-banded and paint-marked birds. The annual breeding season begins in iate February with population build-up and pre-breeding aerial display which functions in pair bond formation and synchronization of individual breeding cycles. Pairs nested from 0 to 91 days after first being recorded on the island. Males play the major role in nest site selection and nest construction. Clutch size is one. The egg is incubated by both parents alternately with attendance periods of 4 to 16 days. Due to decreasing energy reserves, adult attendance periods become progressively shorter as incubation progresses. Hatching occurs after 42 to 46 days (mode = 44 days). The nestling is brooded for about one week. After about three weeks, adults come to the nest only to feed the nestling. Nestlings are fed primarily on flying fish and squid. They complete their growth and leave the island between 67 and 105 days (mean = 84.2 ± .76 days) after hatching. In cases where failure of initial nesting occurred early in the breeding season, some pairs re-nested. In cases of re-nesting, replacement eggs were laid 21 to 80 days after the loss of an egg or nestling. Eggs of re-nestings were significantly smaller in volume (averaging 4.79% less) than eggs of first nestings. Re-nesting was carried out by 54.3 per cent of pairs which failed in 1964 and by 15.6 per cent in 1965. Predation by Polynesian rats accounted for 60.0 per cent of egg mortality and 96.0 per cent of nestling mortality. Total nesting success was significantly higher in 1964 (37.9%) than in 1965 (17.4%). This difference between the two years resulted from differences in both amount of re-nesting and degree of re-nesting success. ...
Fleet, Robert Ryland (1973). Breeding cycle of the Red-tailed Tropic-bird (Phaethon rubricauda) on Green Island, Kure Atoll, Hawaiian Islands. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -183342.