The island of Grassholm is approached from the air. A nursery of gannets gradually becomes visible. The birds nest densely on the island. A man holds a gannet to show the wing-span; this is followed by close ups of the eyes, beak and feet. Birds are sitting on their nests while the mated pairs make bowing and billing movements to each other.

Some birds are seen fighting and a bird which lands on the wrong nest is attacked. A flock of seagulls launches an attack on nests left unguarded. The other gannets ignore them, being preoccupied with staying on their own nests to protect their own young. An egg hatches and we see the development from the new-born chick to a few days old to two weeks old. Gannets feed their young by regurgitating fish. Parents are seen feeding their young. Young birds are seen at various stages, losing their down and the appearance of their first flight feathers.

At four months, the parents desert the offspring. Driven by hunger the young birds are forced to learn to fly and fish for themselves. On a nearby islet, the young, non-breeding birds congregate. Puffins are also found here. A man walks over deserted puffin burrows which have collapsed. A few remaining puffins are seen on the surrounding rocks. Gannets are seen landing and circling the island using slow motion photography. A similar technique is used to observe the gannets diving and attacking a shoal of fish. The final shot again shows the island from the air.