The passage given below is followed by four alternate summaries. Choose the option that best captures the essence of the passage.

Gradually, life for the island’s birds is improving. Antarctic prions and white-headed petrels, which also nest in burrows, had managed to cling on in some sites while pests were on the island. Their numbers are now increasing. “It’s fantastic and so exciting,” Shaw says. As birds return to breed, they also poo. This adds nutrients to the soil, which in turn helps the plants to grow back stronger. Tall plants then help burrowing birds hide from predatory skuas. “It’s this wonderful feedback loop,” Shaw says. Today, the “pretty paddock” that Houghton first experienced has been transformed. “The tussock is over your head, and you’re dodging all these penguin tunnels,” she says. The orchids and tiny herb that had been protected by fencing have started turning up all over the place.

The passage describes how life on the island is gradually improving, particularly for birds like Antarctic prions and white-headed petrels. It highlights that these birds are increasing in numbers as pests are controlled on the island. The absence of pests allows the birds to return, breed, and contribute to the ecosystem positively. The passage also mentions how bird droppings add nutrients to the soil, supporting plant growth. Overall, Option B effectively conveys the central theme of the passage - the revival and improvement of life on the island due to the absence of pests and the positive impact on birds and plants.

Option A incorrectly suggests an increase in the number of predatory birds, which contradicts the positive developments mentioned in the passage.
Option C is incorrect as the passage doesn't explicitly state that this protection is the primary cause of the positive changes.

Option D is more general and doesn't specifically address the absence of pests as a crucial factor in the positive transformation mentioned in the passage.