It isn't unusual for animals to migrate to avoid harsh winters, but the sun-seeking Arctic tern takes this strategy to extremes. The small seabird flies between the Arctic and Antarctic to take in two summers each year and more daylight hours than any other animal. Making a round trip of 35,000 kilometers (21,748 miles), the tern breaks all records for migratory distances traveled.

If the tern takes prize for distance, the salmon surely deserves special commendation for effort. Hatching in rivers, they swim downstream to spend most of their lives at sea. But the hard work comes as they battle against the current and leap up waterfalls to make it home. If this wasn't struggle enough, hungry bears, eagles and people lie in wait for the exhausted fish as they near their goal.

By day, straw colored fruit bats hang from Africa's city trees like assemblages of broken umbrellas. But at twilight, they take gracefully to the air, traveling up to 180 kilometers before dawn and dispersing seeds and pollen as they feed. They span even greater distances by season, and in colossal numbers. Each fall, around 10 million of these "megabats" arrive in Zambia's Kasanka National Park.

Many whales hunt in polar regions but can travel 18,000 kilometers each year to enjoy warmer waters. Scientists had assumed they prefer to give birth in the tropics. But new research suggests they might be migrating for the sake of their skin. Whales need to molt, and in icy waters where their blood supply is drawn away from the skin, dead cells build up and put them at risk of infection.

It's hard to imagine a creature as tiny and fragile as a butterfly undertaking epic migratory journeys. And yet, surfing air currents, the monarch butterfly can travel up to 3,000 kilometers. In summer, they're at home in northern regions of the US, but when temperatures fall, they head south to California or Mexico to overwinter. Roosting together in large numbers helps them keep warm all year.

Leatherback turtles travel up to 10,000 kilometers, from Canada to the Caribbean and Alaska to Indonesia. No one knows how they find their way from feeding grounds rich in their favorite foods like jellyfish to the beaches where they breed. But scientists believe a spot on top of the animal's head may allow light to reach its pineal gland, triggering its journey at the right moment of the year.

The mass movement of wildebeest across the African plains is perhaps the planet's greatest migration spectacle. With no real beginning or end, their circular route takes 1.5 million wildebeest, and a good number of zebras, gazelles and other grazers, through the Serengeti-Mara — crossing crocodile-infested rivers and dodging lions and packs of painted wolves —- in search of fresh food and water.

Famous for their parental devotion, emperor penguins lay their eggs a good 100 kilometers from the Antarctic ocean where they feed. Mother and father must take turns to travel across the ice, fill up on fish, and make the long shuffle back to regurgitate it for their young. Their partner, meanwhile, goes hungry for weeks to shield the chick from cold that would otherwise kill it in minutes.

Animals help pollinate about 88% of the world's flowering plants — and few are better known than the honeybee. Humans have managed these bees for centuries, harvesting their sweet honey and wax to make items like candles. While domesticated honeybees aren't at risk of extinction, beekeepers worldwide are reporting massive colony losses. Threats include pesticides, climate change …

… and the loss of the plants from which they feed. Honeybees, which belong to the genus Apis, are among the main coffee plant pollinators. But research suggests extreme heat is harming bees and coffee production, with growers in Latin America seeing yield declines. Honeybees constitute only a tiny fraction of pollinators. Many of the species, so vital to our food supply, are under threat.

Insects aren't the only pollinators. Tequila and Mezcal lovers should toast to the long-nosed bat. These winged, nocturnal creatures' favorite tipple is the nectar of the agave plant from which tequila is made. The bats get a dusting of pollen when they stop off for a drink. However, conservationists say populations are in decline due to habitat loss, climate change and agave overharvesting.

The fig tree and fig wasp would not exist without each other. Females lay their eggs inside the plant's fruit, crawling through a hole so narrow they lose their wings, becoming trapped. The eggs hatch and larvae burrow out, transform into wasps and fly away, carrying fig pollen with them. While the tree and the wasp are not in immediate danger, scientists say increasing temperatures are a threat.

Robin populations are strong, but warmer temperatures are changing their behavior. American robins, for instance, are starting their migratory journeys to breeding grounds much earlier. Studies have shown other bird species are having fewer chicks because of climate change. If bird habitats are not protected, availability of food and shelter could be curtailed.

Fish face multiple threats from pollution and over-exploitation to climate change. One study found that sustainable fish catches dropped 4% between 1930 and 2010, with China and Japan seeing declines of 15% to 35%, due to warming waters. Some 90% of fish populations are now over exploited or depleted. Billions of people rely directly on a healthy marine ecosystem for food and work.

The durian. It's a polarizing fruit. To aficionados, it's the delicious king of all fruit. To haters, it's a stinky abomination. Whether you love or despise it, you have the flying fox, which is actually a bat, to thank for its existence. The giant bats help to pollinate the tree. Flying foxes are hunted as pests and are also under threat from habitat loss.

Swarms of midges — what a nuisance! Well, actually, we wouldn't have any chocolate without the chocolate midge. The tiny fly is thought to be the only pollinator that can get into the flowers of the cacao tree. These midges prefer wild cacao to the cultivated stuff and are suffering from habitat loss as forest is cleared for cacao plantations. Improving midge habitat equals bigger fruit yields.

In Montreal, states will try to reach an agreement to prevent mass extinction and to protect our ability to produce food as well as the trillions of dollars in ecosystem services, like pollination, provided by nature. But much of the wealth nature provides is unquantifiable, from the feeling of happiness at the sound of a robin's song to the sense of calm conjured by a forest stroll.