It is built for piracy. The lesser frigatebird is the smallest of its kind. Built for piracy and endurance. It is a slender, black seabird with a deeply forked tail and long, narrow wings. It spends most of its life in the air. It never lands on water. It never rests on the sea. This restriction defines its existence. It must stay aloft or find land. The male is all black with a red gular pouch under the throat. During breeding, he inflates this pouch into a bright red balloon. It is the size of a small apple. He sits in his nesting tree. Pouch inflated. Head thrown back. Calling to passing females. It is a performance. The females watch. They choose.
The female is larger. With a white breast and belly. She does not have the pouch. She does not need it. Frigatebirds cannot swim. Their feathers are not waterproof. They fish by snatching prey from the surface. Never landing. Or they steal from other seabirds. A frigatebird chasing a booby will harass it until the booby drops its catch. The frigatebird catches it midair. It is an aerial pirate. Kleptoparasitism is a valid strategy. It saves energy. The flight is effortless. In a stiff breeze, the bird can cover hundreds of kilometres without flapping. It locks its wings and rides the wind. It sleeps on the wing. It wakes on the wing. It lives on the wing.
In New Zealand, lesser frigatebirds are rare vagrants. They are regular in the Kermadec Islands. A tropical outpost in the far north. Occasionally they wander further south. Reaching the North Island coast. It is a tropical bird in a temperate sea. The population in the Kermadecs is small. A few hundred birds nest there. They use the pōhutukawa trees on Raoul Island. The island is predator-free. The birds are safe there. This safety is rare. Introduced predators have devastated other colonies.
The lesser frigatebird is smaller than the
great frigatebird. The female has a white face patch and a white band across the upperwing. The differences are subtle. Birders squint and argue. Identification requires attention to detail. The call is a series of rattles and clicks. Heard only at the breeding colonies. In flight, it is silent. The lesser frigatebird is a bird of the warm Pacific. It comes to New Zealand only at the northern edge. It does not stay.
Introduced predators such as rats and cats threaten breeding islands. Sea level rise threatens low-lying atoll nesting habitat. Plastic ingestion at sea adds another layer of risk. The global population is estimated at 100,000 to 200,000 birds. In New Zealand, it remains a rare vagrant to the Kermadec Islands and occasionally the North Island coast. The numbers are secure globally. Locally, the presence is sporadic. It carries on.