Adam is a freelance naturalist working with Adventure Canada.

THERE ARE OVER 10,000 bird species in the world. A great many of them are relatively easy to find — you simply have to get to the right habitat in the right part of the world. Some are more challenging and take time, money, and effort. But a handful are so elusive, or occur in such isolated or dangerous places, that most birders will never see them in a lifetime of birding.

1. Inaccessible Island rail

This one is as hard to see as its evocative name suggests — it is confined to tiny Inaccessible Island in the southern Atlantic. To even have a chance to see this bird, you must somehow get to the world’s most remote inhabited island — Tristan da Cunha — and then with the Tristaners’ help find a way to get to Inaccessible, notorious for the big swells that dump on its beaches and make boat landings impossible on most days.

Once you’ve made it ashore, you still have to find it — a tiny, flightless black bird that scurries around mouse-like through the grass.

2. Dwarf cassowary

Of the spectacular bird species of New Guinea, none are harder to see than the cassowaries. Ironically, they are the largest native land animals anywhere in Melanesia, but it’s precisely their size that has made them an irresistible target for hunters for 50,000 years.

There are three species of cassowary in New Guinea, and all are very difficult to find, but the dwarf seems to be the hardest. Its preferred habitat is steep hill and montane forests. Judging by its piles of scat and dinosaur-like footprints, it’s pretty common and widespread but seems to have the ability to disappear into the forest long before a human observer has a hope of seeing it.

Researchers spend months or even years stalking quietly through dwarf cassowary territory without seeing a single specimen.

3. Amsterdam albatross

Amsterdam albatross. Copyright Meghan Kelly.

Many of the world’s seabirds have gone extinct in recent centuries due to the introduction of mammalian predators to their breeding grounds. Many others are clinging to the most tenuous of existence. The Amsterdam albatross is one of the rarest and most impressive.

With a wingspan of up to 3.4 meters, it is among the largest flying bird species on the planet. It lives only on tiny Amsterdam Island, a speck of land in the South Indian Ocean administered by France. There are only around 26 breeding pairs every year, all breeding on a small plateau at the top of the island, an area strictly off limits to visitors.

The only theoretical way to see this bird would be to get on one of the supply ships that visit every few months, and you may be very lucky to see it flying around its breeding island. But don’t count on it — most people who sail there don’t. It does range far and wide and is known to feed in waters off Australia and South Africa, but it looks so similar to other large albatross that you’d probably need to sight its leg band to be certain of its identity.

4. Congo bay owl

Owls can be the hardest of birds to see. Among them, bay owls tend to be especially difficult to track down at night in their rainforest habitats. This species is known from only two records in the eastern Congo mountains — a specimen collected in 1951 and a bird mist-netted in 1996.

In addition to being extra elusive, this owl has the distinction of occurring in an area that is so unstable politically that few if any scientists or birders have been willing to risk their lives to try and find it.

5. Scaled ground-cuckoo

South America is the bird continent. With far more species than any other, it’s the place to go to see a huge variety of birds in a short period of time. While most of the South American birds are relatively easy to spot, the five species of ground-cuckoos present a huge challenge to birders, with the scaled being probably the most difficult of all. It’s confined to the lower Amazon in northern Brazil and has only ever been seen a few times.

If you want a chance at this bird, be prepared to figure out a way to access some very inhospitable terrain and endure the stinging bites of the army ant swarms the species habitually follow.

6. Night parrot

The night parrot is as strange as it is elusive, a nocturnal ground-dwelling parrot that lives in remote parts of the Australian outback. Evidence of its continued existence in recent years had been very scant until a few months ago when details of a confirmed sighting emerged from outback Queensland.

So the bird is still out there! But that doesn’t make it any easier to see — details of the discovery have been kept top secret, and finding a night parrot in the outback is still like finding a needle in a haystack, in the dark.

7. Bronze parotia

Without a doubt, birds of paradise are the most extraordinarily plumaged of all birds. Thankfully, the males of many species can be observed displaying in all their glory as they habitually utilize the same display trees or courts early in the morning. Many of these are readily accessible, but some are not.

The bronze parotia is certainly not — it’s confined to the exceptionally rugged Foya Mountains of West Papua, Indonesia. It’s only known from a few sightings during full-scale scientific expeditions to one of the most poorly known mountain ranges on Earth.

8. Ash’s lark

This lark is known from only a small area near Mogadishu, Somalia. It was considered common the last time the site was visited, but that was a long time ago. Until conditions improve in Somalia, this bird is pretty much off-limits.

9. Black robin

Black robin. Copyright Nathan Green.

Like most Pacific Islands over the past thousand years, New Zealand has lost many of its bird species with the arrival of humans. But this nation has also led the way in bringing back the rarest of species from the brink of extinction. No comeback has been more dramatic than that of the black robin.

In the 1970s, the world population was down to five birds, and that included just one fertile female. They were constricted to the tiny and remote Little Mangere Island, in the already remote Chatham Islands. A team led by Brian Bell and Don Merton carefully managed the birds and not only saved them from immediate extinction but reintroduced them to two islands where their population is now thriving.

However, to this day they are confined to those two tiny islands — Rangatira and Mangere — and there are at present no other suitable places to reintroduce the species. Both islands are very remote, and landings are not only difficult to make but actually forbidden by the New Zealand government. And though the robins are very tame they rarely break cover, so sitting offshore in a boat almost never produces a sighting.

10. Dulit frogmouth

Frogmouths are another group of nocturnal birds that can be very tricky to see at the best of times — by day they camouflage perfectly on the branches they sleep on, while by night their bizarre calls may be heard but often very difficult to track down.

This species is the most difficult of all frogmouths — confined to the lower slopes of a few mountains in Borneo, it is almost never heard and even less often seen despite hundreds of birders visiting the island every year.