How high can birds and bees fly?

Doug and George reply:

We always knew someday we’d have to explain about the birds and the bees.

Bees can fly much higher than they do, so we don’t really know the upper limit. If we go by the altitude at which bees occur, they get into the Himalayas, so we can say that some species will fly in areas that are thousands of feet above mean sea level. If there’s anything that seems to be a limiting factor, it’s temperature. Bees have very high body temperatures (a honeybee drone, for example, has a thoracic temperature of about 125 degrees F while flying), and they can’t sustain themselves long if the temperature is low, as it would be at extremely high altitudes. Of course, live insects of other types can be found in the upper atmosphere, when the wind currents are right and the insects are tiny enough that they don’t need to flap to stay airborne–they’re just carried aloft by the winds. They go into a sort of aerial hibernation, thawing out if and when they drop down to warmer atmosphere. Because of this, insects and other arthropods like mites and spiders can get higher into the atmosphere than any other members of the animal kingdom (anything larger would be unable to stay aloft once it was too cold to flap its wings).

But we don’t think floating was what you had in mind. The organisms that fly highest are birds.

The altitude record is held by a Rüppell’s griffon Gyps rueppelli, a vulture with a 10-foot wingspan. On November 29, 1975 one was sucked into a jet engine 37,900 feet above the Ivory Coast in West Africa. The plane was damaged but landed safely. What the bird was doing up so high I have no idea, since this species is not migratory.

The bird that flies highest most regularly is the bar-headed goose Anser indicus, which travels directly over the Himalayas en route between its nesting grounds in Tibet and winter quarters in India. They are sometimes seen flying well above the peak of Mt. Everest at 29,035 ft. Birds have some natural advantages for getting oxygen at high altitudes, in particular an arrangement of air sacs that allows them to circulate inhaled air twice through the lungs with each breath–much more efficient than the in-and-out system used by mammals. Bar-headed geese have special adaptations that make them even better at high-flying than other birds. They have a special type of hemoglobin that absorbs oxygen very quickly at high altitudes, and their capillaries penetrate especially deep within their muscles to transfer oxygen to the muscle fibers.

Other high flying birds include whooper swans, once observed by a pilot at 27,000 feet over the Atlantic between Iceland and Europe, and bar-tailed godwits (a shorebird), which have been seen at almost 20,000 feet. The record for North America is a mallard duck that collided with an airplane at 21,000 feet above Elko, Nevada in July, 1963. Most birds, though, fly lower–waterfowl typically at between 200-4,000 feet, and small songbirds at between 500-2,000 feet. However, the tiny Blackpoll warbler will fly up to 16,000 feet high in order to catch favorable winds on migration between Canada and South America. I’m not sure how well a sparrow would do, but similar-sized birds are quite capable of flying very high indeed.

Doug and George

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