As spring arrives in the mountains, the first flowers appear with the sun, and the chamois descend the slopes in search of the first few blades of fresh grass. The ravens are feeding a brood of noisy youngsters, and, high up on an unapproachable crag, Biker the eagle sits on her nest.

Under the ice, the water of the Alpine lakes never freezes, and fish can survive the harshness of winter. In February, eels and other fish species are spawning, depositing the eggs that will give life to their next generations. Along fast-flowing mountain streams, ice doesn’t form, and the dipper dives in search of invertebrates, crustaceans, and other tiny prey.

In winter, Europe’s greatest mountain range, the Alps, lies blanketed by snow and ice. For the majestic golden eagles, who make these remote and impressive peaks their home, these are hard times, and food is scarce. But one eagle is lucky: An avalanche results in an unexpected meal.

Just how smart are dolphins? Can they tell their own reflection apart from another dolphin? Here we see examples of "self-directed" behaviors that answer this question.

We all know that crows are smarter than the average bird, but will 007 be able to solve the complex puzzle and retrieve his reward?

In the next 35 years, we’ll have to produce more food than all of the world’s production over the last 2000 years combined. So what will the farms of the future look like?

Off the coast of California, an island of floating kelp provides refuge for fish in the open waters. The many small fish then attract larger species, including the ocean sunfish that seek relief from their parasites, and the predatory blue shark.

The harbor seals gather in a sheltered cove to give birth. But even hidden from predators, there is no guarantee of survival, and we witness the tragic death of one newborn that gets trapped in its amniotic sac. Within a few hours, the pups that survive the birth are already into the waves, getting to know their new watery world.

Life can be hard in the Californian desert, but many plants and animals are adapted to survive the hot, dry conditions. Jackrabbits, owls, hummingbirds, and the green stick tree all thrive in this harsh climate as they wait for the rare blessing of rain.

Alive since ancient times, the giant sequoia trees stand colossal and majestic. Deep in the valley, a pair of coyote hunt in the winter snow, while in the Mojave Desert, Joshua trees and cactus plants have adapted to survive the searing heat.

Every fall, the monarch butterflies migrate back to their breeding grounds in California. These fascinating and stunningly beautiful creatures weigh only a gram, yet travel extraordinary distances to complete their lifecycle. In the early spring, deep in the Yosemite valley, the sun warms the wet ground, forming clouds of misty fog.

The Ocean Cleanup is a Netherlands-based, non-government environmental engineering organization that develops technology to extract plastic pollution from the oceans. They have developed a "passive" cleanup system that takes advantage of the natural oceanic forces of wind, water, and currents.

Kelp is a fascinating plant. What we see on the surface has little in common with what's actually there. Californian harbor seals are mammals but they do a lot of hunting underwater.

Everyone's heard of California, but this documentary showcases the state's natural beauty and wildlife. It has a fascinating range of geographical features and is home to many unique species of animals.

In this short animation, produced for primary school children by Green.TV, supported by the Wellcome Trust, we look at the remarkable evolution of the whale from a land-based dog-like animal to the marine mammal that became the world’s largest creature ever.