Reproduction

Magnificent frigatebird

The males attract their mates by perching on small plants, fluttering their wings and bending back their necks to inflate a bright red throat sac.  Males then drum this inflated sac with their own bills to create a signature clattering sound. Once bonded, the pair remains monogamous.The lifespan of Magnificent Frigate birds is expected to be 30 years. Frigatebirds nest in colonies.  Males gather sticks, which the female uses to construct a nest for the single egg she will lay. Clutch size of the magnificent frigatebird is one egg, and the incubation period lasts between 53 and 61 days. After the chick hatches, the male remains an additional month before leaving. The mother cares for her chick for another 13 months, providing it with stolen meals. Frigatebird chicks are altricial and require about six months to fledge.

Northern Gannets

Northern Gannets are the seabirds which belong to Sulidae family. They are colonial but are territorial. The most typical display is the “sky-pointing” with neck, head and bill held upwards. Both mates touch their bills and sometimes shake their heads to communicate. Pair-bonds last all the life and pairs return to the same nesting area each year.Northern gannets live for around 16-21 years. They breeds in huge colonies on sea-cliffs. They breeds a chalky blue egg on islands and coasts.  The clutch is typically 2 eggs. Incubation by both parents lasts 44 days. They do not have brood patches, but their feet become vascularized and hot, and incubate the egg with its webbed feet. At hatching, the chick is near-naked and brooded for the first days. Then, it is covered in white down on the black skin. Youngs are altricial and fledge after 90 days. 

sources

wikipedia

http://www.oiseaux-birds.com