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 correct option is: "In the absence of pests, life on the island is now protected, and there has been a revival of a variety of birds and plants."

Let us break down the passage and analyze how to find the correct summary step-by-step:

Step 1: Analyze the key details of the passage
- The Catalyst: The text mentions that birds managed to survive "while pests were on the island," and now their numbers are increasing. This indicates that the pests are now absent or have been eradicated.
- The Ecological Feedback Loop: The recovery of the birds (Antarctic prions, white-headed petrels) leads to more nesting and breeding. This increases nutrients in the soil through their droppings (poo), which in turn helps plants grow stronger. Stronger, taller plants then protect the burrowing birds from predatory skuas.
- The Visual Transformation: The island's landscape has transformed from a sparse "pretty paddock" into a dense habitat with tall tussock grass, penguin tunnels, and wide-spreading orchids and herbs.

Step 2: Evaluate the given options
- Option 1: "There is an increasing number of predatory birds and plants on the island despite the presence of pests..." This is incorrect. The number of nesting/burrowing birds is increasing, not predatory birds (predatory skuas are actually what they are hiding from). Additionally, the revival is happening because pests are no longer threatening them.
- Option 2: "Flowering plants, herbs and birds are now being protected on this wonderful Antarctic island." This option is too limited. It focus only on protection and fails to capture the core essence of the natural ecological revival and feedback loop.
- Option 3: "There is a huge positive transformation of the ecosystem of the island when brought under environmental protection." While environmental protection is implied, this summary is overly general and misses the critical details of pest removal and the specific revival of flora and fauna described in the passage.
- Option 4: "In the absence of pests, life on the island is now protected, and there has been a revival of a variety of birds and plants." This option accurately and concisely captures the essence of the passage: the eradication of pests has allowed the natural ecosystem to recover, leading to a flourishing revival of both bird and plant life.