A spider found in parts of the Caribbean and South America forms colonies that comprise thousands of individuals. Working together these colonies can build nests more than 20 feet across.

Some animal species congregate in huge groups. Icelandic puffins form colonies of more than a million, which provides shared information about food sources and reduces the odds of being attacked. Social spiders in Ecuador gather by the thousands to capture large prey. Leaf cutter ants in Costa Rica build enormous acre-wide cities to house multimillion-citizen colonies.

The Hebrides islands in Northwest Scotland are home to the largest puffin population in the U.K. Every year, the seabirds congregate in huge colonies in order to find a mate and secure the perfect piece of real estate to raise their young.

"Animal Homes: Cities" features a colony of over 40,000 puffins filmed from every angle imaginable. Cinematographer Mark Carroll explains how he got the close-ups using small GoPro cameras and the clever use of puppets.

Finding a good base of operations is key to successfully raising a family. One must find the correct stream or tree, the correct building materials, neighbors and sometimes tenants. In the wild, every home is a unique DIY project, every head of household is a designer and engineer. Animated blueprints and tiny cameras chart the building plans and progress of many different animal species.

Hooded merganser ducklings brave a 50-foot drop from their nest high in a tree to the forest floor below. They are following the calls of their mother who is waiting to reunite with them at a lake nearby.

The saltmarsh sparrow nests in coastal marshes that tend to get flooded once a month during high tides. Eggs either float away or chicks drown in the rising water. Only chicks that are strong enough to climb can avoid certain death.

Bird nests come in all shapes and sizes, crafted from an inexhaustible diversity of materials, including fur, grasses, leaves, mosses, sticks and twigs, bones, wool, mud and spider silk. Quite a few also contain man-made materials – colorful twine, bits of wire, even plastic bags. Each one is a remarkable work of art, built with just a beak!

A female Anna's hummingbird builds a nest constructed of plant fibers and spiderwebs. Just the right size for her tiny eggs

The opening scene of "Animal Homes: The Nest" features host Chris Morgan walking among a huge variety of bird nests in a darkened warehouse. Producer Ann Johnson Frum explains what went into filming this dramatic scene and gives us a glimpse of the nests' permanent home at the Yale Peabody Museum of Natural History.

Ecologist Chris Morgan travels to the jungles of Northern Sumatra to document the work being done to save its population of wild orangutans. Asia’s most intelligent ape once roamed across the Indonesian islands of Sumatra and Java, but today, fewer than 7,000 Sumatran orangutans remain in the wild. The film cites rapid deforestation as the chief reason for the species’ declining population.

Baby orangutans sometimes need help from their mothers when trying to swing between tree branches.

For centuries, owls have captured our imaginations. With their haunting calls and charismatic faces, these birds remain popular but mysterious because it’s rare to catch more than a glimpse of one in the wild. Unlike their cousins, the hawks, eagles and falcons, owls are the only bird of prey to hunt effectively at night and they have evolved a range of special abilities that allow them to do so.

Evolution has endowed owls with a suite of superpowers: precision hearing, incredible eyesight, night vision. Add to that the power of virtually silent flight, and no prey in their path stands a chance.

Antarctica’s most popular tourist destination is a unique British post office located in the heart of the Antarctic Peninsula at Port Lockroy, about 700 miles south of Argentina and Chile. Enthusiastic cruise ship passengers from around the world come ashore throughout the Antarctic summer to see the colony of 3,000 gentoo penguins that takes up residence each year.

The skua is a large seagull-like bird that preys on penguin chicks. But the tables are turned when the babies are nearly full-grown and sporting feather mohawks.

France is known for its delicious food and wines, great art and architecture and celebrated culture of all kinds. But there’s another side to this popular destination that is not as visible, its wild side. Deep in the French countryside, it is possible for the adventurous to spot brown bears, wild boar, griffon vultures or wolves.

It's a special day for a female European badger living in the Vosges mountains on the border of Germany and France. She's looking for a home in which to rear her cubs--and a mate to father them.

A group of 20 tagged killer whales traveling at fairly rapid speed is followed as they head straight toward the summer nursery grounds of a pod of narwhal and their young. The science team and film crew are stunned as they arrive to see the killer whales lunging at the beach, pinning the entire pod of narwhal in shallow water before devouring them all.

Polar bears need the ice to hunt and as it vanishes they can no longer reach their traditional prey. With each Arctic summer providing more water and less ice, some polar bears are forced to try their luck with seaweed, birds, and Arctic char, a type of salmon, as they migrate upstream to spawn. Their ability to find food and develop new hunting skills may prove crucial to their survival.