Fast fliers, poor hunters
By Nutan Shukla

FALCONS, who are also known as raptors, have a very acute vision. This is because the foveae (parts of retina) of these birds have about 10 lakh (one million) cones per square millimetre compared with a mere two lakh in man, that is one-fifth as compared to falcons. In other words it may be said that the raptors have five times more acute eyesight than humans. While other birds usually have eyesight one time better than man’s, these birds have both their eyes in front of their head. The falcon sees with stereoscopic vision. This allows the bird to judge distances accurately. This is important when it is diving on its prey.

Despite the fact that falcons are fierce and specialised hunters, they often fail in catching the prey. Soviet ornithologist N.A. Gladkov in an observation calculated that out of 3,441 attempts only 213 were successful, that is 6.1 per cent.

Peregrine falcon, the most widespread of the raptors, is a very popular bird because of its speed, agility and efficient hunting. Its normal cruising speed is about 60km per hour, but in the spectacular slanting plunge, usually called a stoop, it can reach a tremendous speed. There are different claims about the speed of the bird. According to some, it can reach to an astonishing steep of more than 400 km per hour while stooping after prey. Some say it can dive at a speed of 360 km per hour at steep angles. Others claim that the bird cannot exceed the speed of 180 km per hour. Since no very accurate determination of speed is made so nothing can be said for sure. In some cases air speedometers were fitted to trained peregrine falcons and the maximum speed recorded was 132 km per hour. Among these birds males (also known as tiercel) are better fliers and may reach far greater speeds in a courtship display dives. The most baffling aspect is how this bird can pull out of such high speed dives without blacking out.

About 50 cm bird, peregrine falcon has 17 races with cosmopolitan distribution. The bird is a very skilful flier. It can change its path even just a few milliseconds before making an impact on its prey.

Despite being the fastest flying bird in the world (as claimed by some), peregrine does not succeed in every attempt to hunt down the prey. Rather it fails in many of its stoops. When the bird is successful, usually there is characteristic trail of scattered feathers leading to the remains of the prey with the breast-bone picked clean of meat. While stooping upon the prey the momentum and the impact is so powerful that the victim may even be decapitated by a slash from the hind toe. Such a killing is quick and probably painless.

Family Falconidae, to which these birds belong, is the world’s most widespread landbird family. Its members are found throughout the world except Antarctica. They are found in a wide range of habitats from deserts to Arctic Tundra. Almost all the falcon species have some common characteristics. Their feet and tarsi are bare and the thighs are covered with loose feathers, giving a pantaloon-like effect. Their upper mandible has a notch. Many species have great dispersive abilities. They are of many sizes ranging from miniature 14 cm Philippine falcon to handsome 60 cm gyrfalcon, the largest of all the falcons.

Most of these birds catch their prey in flight by flying faster than the prey or by diving on it from above. The remarkable hunting capabilities of some of these birds have made them the main birds used in falconry, the sport named in their honour. Falconry is the art of employing falcons, hawks and eagles in the hunting game. It is a very ancient sport and there is evidences of falconry having existed in Assyria as early as 705 B.C. It flourished in the middle ages as a pastime of the privileged classes. There was a time when India was the stronghold of falconry, and the hawk market at Amritsar was famous. As a perfect killing machine, the peregrine falcon holds a pride of place in the sport as well as in its genus ‘Falco’, which includes about 39 species. In falconry it was the nobleman’s bird and severe penalties were imposed on any commoner who harmed the bird. Red-handed merlin, a small European falcon, was known in the heydays of the sport as the Lady’s Hawk.

Sadly, this has led to many birds being taken illegally from the wild and sold mostly to Arab enthusiasts for large sums of money. Thanks to the awareness about the conservation of flora and fauna and the laws enacted to preserve the wildlife, now the trade in wild animals has reduced considerably.

Despite the above mentioned steps the situation is still not very good cuntrary it is bad. Now the culprits are synthetic compounds which are being used in the form of pesticides and insecticides. Of the many compounds introduces into the environment, the organochloride pesticides, notably DDT and the very closely related substances DDE and DDD, are the most commonly studied. They are a group of substances which remain in the environment for many years. In living tissues DDT is converted to DDE, and it is this form which is universally present in the fatty tissues of the world’s fauna.

Large-scale population declines of many kinds of birds, mainly fish-eating and bird-eating species, have been ascribed to exposures to organochlorine compounds, in particular DDT. In Europe and North America the most dramatic declines have occurred in Peregrine falcons, sparrow hawks, ospreys and Bald eagles. These chemicals result in direct poisoning of the birds through the food chain on the one hand, and loss of fertility and unsuccessful breeding attempts through eggshell thinning and breakage on the other. Now the most encouraging part of the story is that many of these chemicals are now banned and the position is much better in many western countries, but the situation in most of the developing countries continues to be the same.

This feature was published on April 18, 1999