Masked Booby    Sula dactylatra 

Etymology :

• Sula: Norwegian name Sula for a gannet -sea bird

• Dactylatra: daktulos –finger; ater black { with black primaries}

• • Melanops: Greek word  melas- black; opos- Face 

Vernacular Names : Guj: Shyam mukh waghomada, Mar: Motha samudri Kawla 

Distribution in India: Pelagic bird seen on western coast of India

Description: It has a size of 81–92 cm; male weighs 1400–1500 g, female weighs 1450–1660 g , wingspan of 152–155 cm.

It is a large booby, with relatively thick bill. The adult of nominate race has all-white plumage except tail and wings, the latter with white restricted to marginal, lesser and median coverts, and some outer primary-coverts, the rest are blackish brown to black.

The underwing has white coverts, remiges are blackish distally and broadly tinged pale silver-grey on bases. The tail is entirely blackish brown to black, except silver-grey tinge to base of central rectrices.

The iris is golden-yellow to amber; bill is straw-yellow with variable olive tinge, largely pale horn with some grey at base; dark slate to black skin around eye extends narrowly to upper bill base and on lores to upper throat

It has less dark on chin and lores; legs are yellow-orange to dull orange, sometimes olive. Sexes similar, but female averages larger and tend to show a larger mask, while male foot tend to be more orange.

The juvenile has dark brown to blackish-brown head, neck and upperparts including upperwing and tail, the junction of lower neck and mantle frosted whitish, or solid white forming hindcollar. The tips of scapulars are frosted whitish grey-brown, less distinct pale tips to lesser coverts and on back to uppertail-coverts; more or less blotched dark brown on rear flanks and rear thighs, otherwise has all-white underparts. The  underwing-coverts are white except dark carpal patch and narrow dark line towards base of wing, while greater coverts have more or less dusky tips. The iris is grey at first; head and neck soon become speckled white, especially around face, white hindcollar becomes broader thus bird looks hooded. The upperparts including marginal and lesser wing-coverts acquire dark brown and white feathers in chequerboard pattern, dark markings on underwing-coverts become reduced and fainter, and iris fades to adult’s colour; last remnants of scattered immature feathers occur on rump, lesser wing-coverts and carpal on underwing.

Races vary in overall size and colour of bare parts. The race melanops has orange-yellow to olivaceous yellow-green bill, often with some grey at base, legs are mid or darkish olive-grey to khaki-olive, the tarsi often greyer, and central tail feathers with little or no silvery grey.

Habitat: It is strictly marine and fairly pelagic. It prefers deeper waters. It nests on rocky islands offshore.

Food habits: It  eats  Shoaling fish, especially flying fish & squid,. The prey is caught by plunge-diving from moderate to great heights. It is normally solitary, or in small groups. It is a frequent victim of piracy by frigatebirds.

Breeding habits:  The breeding is loosely seasonal throughout most of range .They form small to medium-sized colonies of variable density. The nest is a simple circle of accumulated excreta, usually on slope or cliff ledge ,occasionally on flat ground, sometimes on sandy island. They lay a clutch of 2 eggs but brood reduced to one chick as obligate siblicide is practiced. The incubation period is 44 days. The fledging period is 120 days. The post-fledging care is for 156 days.

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