They invoke fear and admiration

Eagles generally kill their prey before carrying it off, and the maximum load for the golden eagle is usually only about 4-5 kg, observes Nutan Shukla

FOLKLORE abounds with stories of birds carrying fantastic weights, but most are entirely fanciful. They generally involve birds of prey which have always filled man with admiration, and even fear. Yet the largest raptors, the vultures, are primarily carrion feeders and have neither the reason nor the claws for great lifting feats. Thus it is to the eagles that man has turned his attention, and of these the very widespread golden eagle has been the subject of most stories.

Eagles generally kill their prey before carrying it off and the maximum load for the golden eagle is usually only about 4-5 kg. But when birds have been disturbed at a kill or sense that a rapid exit is advisable, then there is reason to tackle greater loads.

Most tales of human babies, children and even adults being carried off by eagles have, not surprisingly, been disregarded by ornithologists, but there is at least one case which is apparently fully authenticated. In 1932 a four-year-old Norwegian girl is said to have been carried off by a white-tailed sea eagle while she was playing in the yard of her parents’ farmhouse. The huge bird tried to carry the girl (apparently small for her age) back to its eyrie 800 ft up the side of a mountain more than 1.6 km away, but the effort was too great and the poor child was dropped on a narrow ledge about 50 ft from the nest. Fortunately, a search party organised by the desperate parents pinpointed the eagle soaring above the eyrie and the girl was found in an unconscious state, but unharmed, except for some scratches and bruises. One theory is that the bird had the advantage of the powerful up-current of air. But whatever the truth, the girl, Svanhild Hansen, grew up happily and kept the little dress she wore that terrible day, with the holes made by the eagle’s talons.

The diet of the white-tailed sea eagle in Norway is generally 60 per cent fish and 40 per cent birds but may reach 90 per cent fish in some areas. They sometimes kill Arctic foxes and lambs, but mammals are mostly eaten only as carrion. Where fish are too large to lift, the bird will tow them to land by ‘rowing’ with its wings. The largest prey so far seen taken in flight is the greylag goose, which rarely has a maximum weight of about 4.25 kg.

Another member of the family is harpy eagle, which is probably the most aggressive and powerful true eagle. It is a formidable aerial hunter of the jungles of Amazon. Many experts are of the opinion that this bird should be given pride of place in the entire bird of prey family. Inhabiting the lowland tropical forests, harpy is a very agile hunter, despite its huge size. While on a hunting expedition it cruises through the canopy of the jungle trees at a speed of about 80 kph, chasing monkeys that make up a major part of its diet. It also feeds on sloths, tree porcupines and other tree-living creatures. It is expert in killing and carrying off monkeys and sloths. Its short, broad wings help it to lift prey almost vertically and there is a report of a female rising over 18m with a 5.9 kg sloth in her massive claws.

Other reported great lifts include a Pallas’s sea eagle barely managing to fly with a carp of 5.9 kg in India, and an American bald eagle flying well with a 6.8 kg mule deer in its talons. It is generally assumed that larger individuals among eagles can carry larger weights and it has been suggested that a very large female Steller’s sea eagle of 8.6 kg could probably carry a 9.1 kg young seal for several hundred metres.

This feature was published on February 21, 1999