Nearly 10,000 bird species live on Earth, most of which are doing OK. But many also face threats like deforestation, hunting, invasive species and climate change, and about 12 percent are now on the worst perch of all: the brink of extinction.

Hundreds of rare birds may vanish within a century, which isn't just bad news for them. Birds offer an array of ecological services to keep habitats humming, and often act as sentinel species, hinting at an ecosystem's health like canaries in a coal mine.

That's the motivation for National Bird Day, held annually on Jan. 5 to rally support for endangered birds around the world. Organized by California nonprofit Born Free USA, the day focuses mainly on ethical and ecological issues with the pet-bird trade, but also covers other dangers such as habitat loss and exotic predators.

"On January 5, we will reaffirm our commitment to birds everywhere and acknowledge that the fight for their freedom and survival is not over," Born Free CEO Will Travers says in a statement. "With 46 million birdwatchers in America, the market is ripe for respecting and appreciating birds in their natural habitat. National Bird Day is a chance to consider the welfare of all birds — from the cage to the back yard to the skies across the globe."

In honor of National Bird Day, here's a look at 14 endangered birds whose existential dilemmas warrant at least a tweet in the year ahead:

Araripe manakin

(Photo: Rick Simpson/Wikimedia Commons)

The striking, critically endangered Araripe manakin was unknown to science until 1998, when it was first reported in northeastern Brazil. Only about 800 exist in the wild, all within roughly 11 square miles of forest. Much of their habitat has been cleared for a variety of human uses, including cattle pastures, banana plantations, homes and a water park.

Madagascar pochard

(Photo: Frank Vassen/Flickr)

The Madagascar pochard was thought to be extinct after fruitless searches in the 1990s, but it miraculously reappeared in 2006 when scientists found 29 adults living at a volcanic lake. Although the diving ducks are among Earth's rarest birds, their wild population is now supported by a captive breeding program and protected by permanent guards.

Blue-throated macaw

(Photo: Steve Wilson/Flickr)

Bolivia's blue-throated macaw has suffered mightily for the international pet trade, which caused its wild population to plummet in the 1970s and '80s. Bolivia banned live exports of the critically endangered parrots in 1984, but deforestation still threatens the roughly 120 wild survivors — a total many times smaller than the global number kept as pets.

Bali mynah

(Photo: Brian Jelonek/Flickr)

Also known as the Bali starling or Jalak Bali, this majestic mynah serves as the official mascot of Bali, Indonesia. It's a critically endangered species due to decades of illegal trapping for the pet trade, with only about 115 wild specimens confined to three small habitats. Meanwhile, an estimated 1,000 Bali mynahs live in captivity around the world.

Philippine eagle

(Photo: Shankar S./Flickr)

The Philippine eagle (aka monkey-eating eagle) can live for 60 years and grow nearly 3.5 feet long, making it the largest eagle species alive today. It's critically endangered despite its role as the Philippines' national bird, losing swaths of habitat over the past 50 years to widespread deforestation. Recent surveys suggest 90 to 250 mating pairs still exist.

Millerbird

(Photo: R. Kohley/U.S. Fish and Wildlife Service)

The millerbird is a Hawaiian warbler split into two subspecies, each from its own tiny island. One, the Laysan millerbird, has been extinct since 1923 due to non-native rabbits and livestock overeating local vegetation. That leaves just the critically endangered Nihoa millerbird, whose population on 173-acre Nihoa fluctuates between 50 and 800.

Golden white-eye

(Photo: Peter/Flickr)

Golden white-eyes live on two of the Northern Mariana Islands, Aguijan and Saipan, but the latter is home to 98 percent of them. Despite a total population of 73,000, the species is deemed critically endangered due to Saipan's recent invasion of brown tree snakes, exotic predators that have a history of decimating native birds on small islands.

Trinidad piping guan

(Photo: Heather Paul/Flickr)

Known locally as "pawi," this turkeylike curassow cousin haunts the rainforest canopy in Trinidad. Both its range and population have shrunk in recent decades, due to poaching (it's been legally protected since 1963) as well as habitat loss to logging and farming. Between 70 and 200 Trinidad piping guans are now thought to exist in the wild.

Northern bald ibis

(Photo: Richard Bartz/Wikimedia Commons)

Once common across the Middle East, North Africa and southern Europe, the northern bald ibis has been in a slow, mysterious decline for centuries, leaving just a few hundred in Morocco, Turkey and Syria. Scientists think unidentified natural factors are behind the long-term decline, but the faster pace of recent losses is also blamed on human activities.

Whooping crane

(Photo: John Noll/U.S. Department of Agriculture)

Whooping cranes, the tallest birds in North America, are still in the early stages of an unlikely comeback. Overhunting and habitat loss had reduced the species to just 15 birds by the 1940s, but thanks to intensive conservation efforts — including the use of ultralight aircraft to teach young cranes how to migrate — the population is now up to about 600.

Golden-cheeked warbler

(Photo: Jason Crotty/Flickr)

All golden-cheeked warblers nest in the old-growth, oak-juniper woodlands of central Texas, then spend winter in various parts of Mexico and Central America. The endangered birds are being squeezed in both habitats, mainly by construction, agriculture and reservoir development in Texas and by logging, burning, mining and cattle grazing elsewhere.

Yellow-eyed penguin

(Photo: Ross Land/Getty Images)

The yellow-eyed penguin eschews the close-knit communities and frigid environments of many penguin species, opting for a more spread-out, less sociable life in New Zealand's coastal forests. It's also one of the world's rarest penguins, although conservation efforts have recently helped it rebound to more than 400 pairs on mainland New Zealand.

Amsterdam albatross

(Photo: Vincent Legendre/Wikimedia Commons)

The Amsterdam albatross is a broad-winged seabird that breeds nowhere but Amsterdam Island in the southern Indian Ocean. It relies on just a dozen or two mating pairs, and their ability to raise chicks is hindered lately by grazing cattle, feral cats and longline fishing as well as naturally occurring diseases like avian cholera and E. rhusiopathidae.

Puerto Rican nightjar

(Photo: Mike Morel/U.S. Fish and Wildlife Service)

The mottled, 8-inch Puerto Rican nightjar easily blends into the forest floors and scrublands of its namesake island, but those habitats are increasingly fragmented by residential, industrial and recreational development. The species is endangered, but still has several hundred mating pairs, each of which can raise one or two chicks at a time.