Nesting Activities of the Red-Footed Booby in British Honduras

Abstract

FROM 14 February to 9 May 1958 I conducted an intensive investigation of the breeding activities of the Red-footed Booby (Sula sula sula Linnaeus) on Half Moon Cay, 80 km east of Belize, British Honduras. The detailed results of the study appear in my thesis for the degree of Master of Science (Verner, thesis submitted 1959). Half Moon Cay (Figure 1) is a tiny coral island, 1.16 km in length, supporting mainly coconut palms (Cocos nucifera). The floor of the narrow eastern half of the cay has been cleared, and the palms there are planted in rows. On the western portion, exclusive of the booby colony, the palms are distributed naturally, the floor beneath being covered with lush, mat-forming herbs. Within the booby colony very few palms are present; instead, eight species of broadleaf trees form a nearly continuous overhead canopy from about six to 15 meters above the ground. The number of booby nests in each species of tree fairly well indicated the relative abundance of each species (Table 1). The floor of the colony is composed of coral stones, which permit potential humus to percolate away with the rains. As a result, there is little in the way of an herbaceous understory. The only undomesticated mammal on the cay is Rattus rattus. Ninetyeight species of birds were recorded during the course of the study. At least 77 of these were migratory forms, and, of these, only 17 were recorded regularly enough to indicate that they winter on or near the island. Two species, the Red-footed Booby and the Magnificent Frigate-bird (Fregata magnificens), were nesting at the time of the study; and probably both the White-crowned Pigeon (Columba leucocephala) and the Groove-billed Ani (Crotophaga sulcirostris) nested there later in the year. A number of small lizards and two larger ones, the False Iguana (Ctenosaura similis) and the Iguana (Iguarna iguana), were abundant. Nothing was observed to substantiate the many reports that these larger lizards harm nests, eggs, and young of the Red-footed Booby. The climate at Half Moon Cay is generally mild, although the high humidity makes even slight temperature differences more noticeable. Temperatures were recorded three times daily-morning, noon, and night-between 20 March and 7 May and the range was from 23?C (730F) to 320C (900F). With the exception of the early morning average of 26?C (790F) in March, all three daily averages for March,