Fourth episode examines how plants either share environments harmoniously or compete for dominance within them. Attenborough highlights the 1987 hurricane and the devastation it caused. However, for some species, it was that opportunity for which they had lain dormant for many years. The space left by uprooted trees is soon filled by others who move relatively swiftly towards the light. The oak is one of the strongest and longest-lived, and other, lesser plants nearby must wait until the spring to flourish before the light above is extinguished by leaves. Tropical forests are green throughout the year, so brute force is needed for a successful climb to the top of the canopy: the rattan is an example that has the longest stem of any plant. As its name suggests, the strangler fig 'throttles' its host by growing around it and cutting off essential water and light. Some can take advantage of a fallen tree by setting down roots on the now horizontal trunk and getting nutriment from the surrounding moss and the fungi on the dead bark. The mountain ash (eucalyptus regnans) grows so tall, that regeneration becomes a considerable problem. It is easily flammable, so its solution is to shed its seeds during a forest fire and sacrifice itself. It therefore relies on the periodic near-destruction of its surroundings in order to survive. Attenborough observes that catastrophes such as fire and drought, while initially detrimental to wildlife, eventually allow for deserted habitats to be reborn.

In this bird's-eye view of two continents, demoiselle cranes negotiate a dangerous Himalayan pass on their way to India while high-flying bar-headed geese take the fast track five miles above. In Rajasthan, vultures watch hunting tigers hoping for a meal and pigeons visit a temple dedicated solely to sacred rats. Pigeons are also our guide to the greatest gatherings of camels on Earth and learn to dodge buzzards around the battlements of Jodhpur Fort. 9,000 cranes overwinter in the most unlikely of spots - a barbed wire compound in the centre of a desert town. In Australia, rainbow lorikeets drop in on Sydney and patrol Australia's Gold Coast. In the outback, white cockatoos swirl in thousands and budgerigars pass Uluru (Ayers Rock) and gather in the biggest flocks ever recorded. In China, swallows and swifts visit the Great Wall and the Forbidden City of Beijing. In Japan, the country's most revered birds - Japanese cranes are fed fish by appreciative locals and are joined in strange, momentary harmony by hungry red foxes, white-tailed eagles and Steller's eagles. As peace descends, Japanese cranes dance beautifully in the snow.

In the first episode, Sir David Attenborough reveals the unexpected wildlife riches of the British Isles, showcasing the dramatic and spectacular habitats that rival any across the globe. This journey uncovers the diversity of life in the UK's unique landscapes, from the intricate world of bumblebees to the swift lives of kingfishers. The episode captures extraordinary scenes of nature, including killer whales preying on seals, golden eagles in the Scottish mountains, the cunning tactics of woodland plants, and the perilous life of puffins evading gulls. It highlights Britain's geological diversity as a cornerstone of its natural wealth, contributing to an array of habitats and supporting a wide range of life.
Britain's importance extends to being a haven for migratory birds, with our seas feeding 65% of the world's gannets and supporting the largest colony of northern gannets on Scotland's Bass Rock. The west coast of Scotland offers sanctuary to barnacle geese due to its abundant food and mild climate, though they remain vigilant against hunting sea eagles. Despite these natural treasures, Britain faces challenges as one of the most nature-depleted countries globally. Sir David Attenborough emphasizes the need to conserve and restore these wild isles for the enjoyment and benefit of future generations.

The third episode of the series takes viewers on an enthralling journey through the diverse ecosystems of the most species-rich continent on earth. It highlights the resilience and challenges faced by the unique wildlife, from the Atacama Desert to the Amazon Rainforest. The documentary showcases the remarkable interactions between creatures like black spider monkeys, parrots, and Capuchin monkeys, emphasizing the delicate balance between human needs and the preservation of South America's biodiversity. The film also captures the rare and thrilling moments of puma hunting, providing an intimate look at the struggles of a mother puma named Sarmiento.
South America's extraordinary landscapes, wildlife, and their coexistence with humans are beautifully depicted in this documentary.