Birds that have their normal habitat in the lowlands fly at a higher level during migration than at any other time. For instance, migrating pelicans, ducks and cranes have been observed flying at 3,000 to 8,000 feet (900 to 2,400 meters). Lapwings and larks have been sighted at over 6,000 feet (1,800 meters), while plovers and sandpipers have been seen flying at 10,000 to 12,000 feet (3,000 to 3,700 meters). In each case, these heights were sufficient for the birds to clear obstacles in their path. Could they have flown higher?

From observational reports, the answer is, Yes. In the Himalayas some years ago, two types of lowland birds​—curlews and godwits—​were noted flying at 20,000 feet (6,000 meters).

It has also been observed that high-flying migrating birds may drop down to lower altitudes during bad weather. This suggests that they are not bound into some inflexible flight pattern, but, rather, will instinctively choose to fly under instead of over a storm in order to pass it.

Even the hopping birds that we enjoy watching in our gardens often are very seasoned travelers. Blackbirds, thrushes, finches, tits and those tiny bundles of energy, the wrens, travel widely and regularly.

In the autumn vast numbers leave their nesting sites in Scandinavia and eastern Europe and fly south and west toward Britain, to enjoy the milder winters. Then they make their way back in the spring. Radar observations on the east coast of Britain have revealed that these small birds arrive generally at speeds under 30 miles (48 kilometers) per hour and at heights of less than 3,000 feet (900 meters).

High-flying Hummingbirds

Since ability to fly high is noted among many large birds, it may seem odd that some varieties of hummingbirds have been observed on the wing at a height of 16,000 feet (4,900 meters). This tiny creature is one of the few birds able to fly backward momentarily. Astonishing, too, is the speed of its wingbeat. It does not seem possible that the ruby-throated hummingbird, found in the United States and Canada, may flap its wings from 50 to 70 times per second. Yes, per second! Contrast this with the wingbeat of the pelican, which needs to flap its wings only 1.3 times a second to keep flying.

Obviously, one would question how the tiny hummingbird could possibly have enough energy to reach 16,000 feet (4,900 meters). But the answer is simple enough. Those hummingbirds seen at this height were in the vicinity of perpetual snow in the Ecuadorian Andes, mountains that range from 8,000 feet (2,400 meters) to peaks over 20,000 feet (6,000 meters). Since these particular birds are known to live high in the Andes, they have a good start in achieving a great height when flying.

‘Dwellers on the Heights’

Hence, it is understandable that other ‘dwellers on the heights’ are observed flying high. Among these is the Andean condor, a giant bird that ranks in size with the California condor and is at home in the highest elevations of the Andes. So, it is not surprising that one of these birds was seen flying with apparent ease in the thin air some 6,700 feet (2,040 meters) above an Andean peak of 12,958 feet (3,950 meters).

Possibly the greatest known recorded height attained by birds in flight was that achieved some years ago by a flock of geese in migration across the lofty Himalayas. At that time scientists were photographing the sun over India when they saw the geese flying in V-formation at the height of Mount Everest, around 29,000 feet (8,800 meters).

What about the high-flying bird seen by Sir Edmund Hillary and his guide? Neither man was able to identify it. It may have been that huge vulturelike bird, the lammergeier. On occasion lammergeiers have been spotted flying at 24,000 to 25,000 feet (7,300 to 7,600 meters) in the Mount Everest area.