Masked Booby  |  

The largest and heaviest of the booby (Sulidae) family, the Masked Booby has a streamlined white body with a narrow (from base of bill to just behind the eyes) black mask on the face, and long narrow wings of mainly white with black tips to the flight feathers. The pointed bill on most individuals is yellow with a black base, however can vary from yellow-green, olive, rosy pink to orange (NSW NPWS 1999cq). The tail is also pointed. The Lord Howe Island population, which belongs to the S. d. tasmani subspecies, has brownish eyes, compared to birds at most other locations which have yellow eyes (NSW DECCW 2005op). The Masked Booby is 75–85 cm long, with a 160–170 cm wingspan and weighs 1200-2200 g (Marchant & Higgins 1990; NSW NPWS 1999cq). Sexes are alike, but the male has a brighter yellow bill, and there is no seasonal variation in plumage (Lindsay 1986; Marchant & Higgins 1990). Juvenile Masked Boobys are mostly grey-brown above and white below, with a diagnostic white collar and dark hooded appearance (Marchant & Higgins 1990; NSW NPWS 1999cq). The Masked Booby is a more solitary bird when flying or feeding than other species of booby or gannet, but will form loose congregations most notably on return to breeding islands, and breeds colonially and roosts in groups (Marchant & Higgins 1990).