All you need to know about peregrine falcons: the facts

The facts about peregrine falcons

The fastest bird in the world with a formidable hunting style, the peregrine falcon is a bird of prey that has inspired many of my paintings. Read on for some fascinating facts about peregrines. 

A peregrine's other name is 'the wandering bird'

The name peregrine falcon comes from the Latin word 'peregrinus', which means 'wanderer' or 'pilgrim. It is so named because outside of the breeding season these birds travel widely. The scientific name for a peregrine is Falco Peregrinus.

How to identify a peregrine

About the size of a crow, a peregrine has a blue-grey back, barred white underparts, and an almost black head. Females are bigger than males. The barring of a peregrine's feather pattern means it is often mistaken for a sparrowhawk. To tell the difference, look for the peregrine's dark eyes, long pointed wings and short tail. In contrast, sparrowhawks have striking yellow eyes, short wings and a long tail. Peregrines are also characterised by their horseshoe moustache: black marks that reach down below the eyes. It looks as if the bird is wearing a mask.

The fastest animal in the world.

When in full stoop, diving for its prey, a peregrine can reach speeds of 242 mph making it the fastest recorded animal. Special adaptations in this bird's nostrils enable it reduce the change in air pressure experienced at this speed so that it can breathe. These small bony tubercles guide shock waves of air entering the nostrils so that the extreme pressure doesn't damage the bird's lungs.

Peregrine's influenced jet engine design

Scientists designing the first jet engines used the peregrine's nostril as a model. Researchers were confused by the fact that aeroplane engines started choking out at a certain speed. The air, instead of going into the cowl of the engine, encountered a wall of still air and split around it. Wondering how it was possible for falcons to be able to breathe at speed, the scientists found the answer inside the birds' nostrils. Here they discovered a small cone that protrudes slightl. They fashioned a similar cone in the opening of jet engines so that air could pass into the engines at great speeds.

Binocular vision

Peregrines are thought to enjoy binocular vision, eight times better than our own. They can see their prey from a distance of more than three kilometres. They also have a third eyelid to protect their eyes as they stoop to dive. This spreads tears and clears debris without obstructing vision. Studies also show that a peregrine sees more clearly when its head is turned at a 40 degree angle.

Their flight is curved

You can tell a peregrine in flight by the way it cruises with rapid steady wing beats and then drops like a bullet onto prey. It's eyesight means it can see better when its head is turned and so it flies in a curve towards its prey. Interestingly this curved approach proves to be quicker than a straight one because there is less drag slowing the falcon down.

Peregrines mainly eat pigeons

Pigeons make up the main diet of a peregrine falcon. However during the migratory season these birds also pick off small ducks, quails, moorhens, ringed and golden plovers, starlings, swift and little grebes. Urban birds hunt at night, hunting by street light.  Read about the diet of a pair of industrial peregrines I watched here.

Formidable hunters

A peregrine falcon hunts most often at dawn and dusk, when their prey is most active.  Once it spots its prey, a peregrine begins its stoop, folding back its tail and wings, and tucking in its feet. It strikes with a clenched foot, stunning or killing its prey with the impact, then turns in mid-air to catch it. If it misses, the falcon will chase its prey in a twisting flight. If the prey is too heavy to carry, a peregrine will drop it to the ground and eat it there.

Impressive courtship displays

Their courtship is spectacular to watch. It involves a display of dynamic aerial acrobatics, precise spirals, and steep dives during which the male passes gifts of prey to the female in mid-air. To make this possible, the female actually flies upside-down to receive the food from the male's talons.

Breeding and nesting

Males are known 'tiercels' and can be up to 30% smaller in size than females. Both birds reach sexual maturity at one year and mate for life. Pairs return to the same site to nest each year. They nest in a scrape, normally on cliff edges or, in recent times, on tall human-made structures. This bird is the most highly successful example of urban wildlife, often choosing ledges on skyscrapers, medieval cathedrals (click here to read about a peregrine pair I watched on York Minster) and on industrial factories. (click here to read about a pair I watched on a chemical plant in Hull).

Peregrine chicks

Peregrines lay up to five dark brown, speckled eggs  These are incubated for 29 to 33 days, mainly by the female, with the male also helping during the day. After hatching, the chicks are covered with creamy-white down and have disproportionately large feet. At this point both male and female leave the nest to hunt to feed their young. They have to work hard since peregrine chicks grow very rapidly. In six days they double their weight and at three weeks old they are 10 times their size at birth. Chicks fledge 42 to 46 days after hatching, and remain dependent on their parents for up to two months.

A protected species

Peregrines are a Schedule 1 listed species of The Wildlife and Countryside Act. They became a target during World War II when they were killed in order to protect homing pigeons. But populations reached critical levels in the 1960s due to human persecution and the impact of pesticides in the food chain.  Improved legislation and protection has helped the birds to recover. However, they are still persecuted - birds are illegally killed to prevent predation on game birds and racing pigeons. They also have eggs and chicks taken for collections and falconry.