The Peregrine Falcon

Since we named our two binocular series falcon names, we thought it would be a good start for the Bird Talk section to tell you a little about Peregrine falcons. The reasoning behind naming binoculars after these swift flying birds has to do with several correlative features, of which vision and speed are the most outstanding.

Below are some observations of these marvelous flyers.

The Peregrine Falcon probably occupies a larger portion of the land surface of the globe (thinly) than does any other bird, though absent from most of South America.

Although the Falconidae contains only about fifty-five species as compared with roughly four times that number in the Accipitridae, the contrast between the almost gallinaceous, weak-billed arboreal caracaras of the genus Daptrius and a Peregrine Falcon is as great, perhaps, as only found in the larger family. Falcons are bird eaters, unlike eagles.

In species of somewhat more sluggish habits, those in which, for example, rodents, reptiles, or insects form a large part of the diet, the sexual size distinction is less. This may be observed even within a genus, for instance a Kestrel as compared with a Peregrine Falcon. This helps to give the immatures an unkempt, less compact appearance than the adults. The same is true in the Peregrine, except for the primaries, which are the same length as in the adult, perhaps because the mechanics of the falcon flight require precision.

Sight is developed to a marvelous degree:

They are equipped with full-color vision and with eyes specially adapted to permit rapid adjustment of focus while moving at speed, and from four to eight times the resolving power of the human eye. Hovering may be compared to looking into a field from a car moving at twenty miles an hour or from one which comes to a standstill every few yards. It would be possible for a human being to see an individual rabbit or large game bird at a range of 600-700-yards; a bird of prey, with about four times the resolving power of the human eye, should therefore be able to see it at a range of nearly two miles.

Peregrine Falcons with an average body weight of 683 grams consume on average 104 grams of food daily in winter, or about 15% of their body weight. The requirement fell in summer.

Prey:

A few species of birds of prey are known to cache or store food on occasion, returning to it later. This is a well-known habit of the American Kestrel, is recorded in the Peregrine, African Hobby, and Goshawk, and may be more common than is thought. Although rarely, the Peregrine Falcon has been known to snatch a fish from the surface of the water.

It is not uncommon to be struck by a Peregrine Falcon when approaching its nest and the same is true of the Black Kite:

Distraction behavior has been observed in the Peregrine Falcon in that the birds threatened an intruder with maximum intensity in an area away from the nest.

In the Peregrine Falcon the male flies from ledge to ledge on the nesting crag, calling, but it seems to be the female who finally picks the actual nest ledge. Young Peregrine Falcons in the nest appear at this stage to be enveloped in a copious woolly garment, though they can stand and walk about.

Peregrine Falcons live longer than Kestrels, and Marsh Harriers longer than Montagu’s Harriers.

Finally, and most spectacular of all, there are a few species of birds of prey which habitually kill other species in flight by a tremendously fast and accurate stoop, or by rapid pursuit. They include the swift falcons of the chase, the Gyrs, Sakers, Peregrine and Lanners, and also small falcons such as Merlins and Hobbies:

These are aerial killers and limited by the fact that their prey must be on the wind before they they can kill it. Pigeons are safe from a Peregrine as long as they stay on rock ledges, and the Bat Hawk does not pursue bats into caves and snatch them from the ledges. The highest speed which has been recorded with even reasonable accuracy was of a Peregrine Falcon which stooped at 275 miles an hour.

Falconry:

The method of using these birds differs, according to the species and the quarry it is flown at. The Peregrine Falcon, generally accounted the best of all those in regular use, is trained to ‘wait on’, and prey on the ground below is put up for the falcon to kill.

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