Birds of prey

In the Friulian Dolomites birds of prey are very common and very charming to be observed in their natural environment, but unfortunately rare to find, especially the night ones.

Birds of prey can be of medium or large size and usually females are larger than males. This feature is most pronounced in the birds of prey with predatory attitudes that feed primarily on birds, while it is reduced in those that catch rodents, insects and reptiles and it is almost non-existent or even reversed in the scavenger species such as the griffon.

The head of these birds is compact and aerodynamic, the beak is pointed and characterized by a strongly curved upper mandible; it is mainly used to chop, clean and eat the animals taken; the structure of the legs varies greatly in relation to the habits of the different species, for instance hawks have very long fingers suited to capturing birds in flight.

The eyes of birds of prey are more developed than the size of the body, the bone structures around the eyes provide an attack balance to the muscles that regulate the opening of the pupil, the lens curvature and the small eye movements and all help to quickly locate, to focus accurately and adapt well to different light intensities. All these characters also denote a high visual acuity: birds of prey are in fact able to distinguish a form in movement from a great distance and the resolution power of their eyes is probably higher than that of all other vertebrates.

The eyes are protected and cleaned both from normal eyelids and by a third transparent eyelid with horizontal scrolling, called nictitating membrane; during flight this membrane falls on the eyes and prevents an excessive dehydration and it is also lowered during fights.

Some of the most common species can be found in the section:

Hospitalized birds of prey – Recovery Center of Andreis (PN)

Eagle owl

Gufo reale

  • Length: 65 – 80 cm
  • Wingspan: 160 cm
  • Weight: 1700 – 4000 gr.

It is the largest among the night birds of prey with reddish plumage, orange eyes and distinctive ear tufts.

It chooses to nest exclusively in peaceful slopes among rocks and woods close to the valleys or even higher up in the mountains.

Its verse is like a “huh” that echoes throughout the walls of the rocky gorges, together with the hard crash of the beak, a breath and a screeching sound.

Its nutrition is mostly made up of wild mice, hedgehogs, crows, reptiles, frogs and insects.

Most common causes of injuring: sometimes it can assimilate poisoned preys, be prey of hunters or it can also be a victim of the road traffic.

The golden eagle

Aquila

  • Length: 80-90 cm
  • Wingspan: 210 cm
  • Weight: 3000-6000 grams.

The golden eagle is a bird of prey of enormous size which can exceed two meters in wingspan. It prefers open areas and summit pastures, where it finds its prey such as marmots, hares and grouse, but also weasels and foxes. It can hunt both by ambush, placed on a tree or on the rocks which enable a panoramic vision, and by surprise, flying to hide behind natural obstacles. Very often these birds of prey hunt in pairs: one flies low to scare the prey, while the other attacks.

Its features are definitely the impressive size, reddish color and particular wings, especially the primary flight feathers that in flight take the form of an “open hand” making this beautiful bird of prey easily recognizable.

The eagle as a divine symbol was born at least 4000 years BC in the cultural cradle of Central Asia, going from there to Asia Minor from the end of the second millennium BC thanks to the expansion of the Hittites. Since then the eagle occurs in all cultures of the Indo-European and Indo-Aryan Semitic families.

The eagle takes today a new and more modern symbolic role in the conservation of nature, becoming the institutional symbol of the Friulian Dolomites Natural Park.

Dimensions

The golden eagle is about 76-93 cm long, 28-34 of which belong to the tail, it has a 190-240 cm wingspan and it weighs between 3 and 6 kg. Females are on average 10% larger and 20% heavier than males. The differences between male and female within a pair may however also be smaller or much more marked.

Flight

In gliding flight the eagle expresses a sense of grandeur and majesty. The flight is powerful and clean, without any wobble or continuous adjustments that smaller birds of prey are forced to do to counteract the wind and air flow irregularities: master of air, it twirls fluidly even with high winds that force buzzards and imperial ravens to a vigorous flapping flight. It is visible even from a great distance and recognizable by the apparent slowness of its flight.

Plumage coloration

The eagle color changes over the years, allowing you to easily recognize three age stages: young (1st year), immature and sub-adult (2-7th year) and adult.

The adult is characterized by a brown color that in the distance may look uniform but it is actually varied, with wings and tail marked by stripes of different shades from beige to milk chocolate on the wing for attrition of the coverts and typically golden blonde top (hence the scientific name of the species is Aquila chrysaetos).

The young have two large white spots on wings that in the distance appear as two spots almost round and for the white tail base. The brown parts are more uniform than in adults and they have a beautiful dark chocolate shade. As the young grows the extension of the white parts  reduces with the appearance of wing spots often before the caudal ones. In vaulting, if you are lucky enough to be at the same altitude or above the eagle, the white spots on the wings and tail are also visible on the dorsal side. In some special lighting conditions, such as when the eagle flies with clear sky over a snow stretch in the sun, the inferior side of the adult eagle’s wings may look very light and suggest, if the observation is short and distant, a sub-adult example.

Eyes, beak and legs

The golden eagle observed up close has light amber-brown iris, long legs suited to catch moving preys covered with feathers (trousers) to the base, with bare and yellow fingers. The toes are strong and have large hooked claws, particularly developed in the first and second fingers, that closing on the prey in opposition to each other, give the greatest strength to the paw grasp.

The eagle kills almost exclusively with the close of the claws, able to stifle or pierce their prey, while the beak is used mostly to tear the dead prey and unscrew the pieces or to cut pieces suitable for transportation. The eagle’s legs are capable, at the time of capture and killing of the prey, to exercise a pressure of 70 kg per cm²: more than three times the maximum power of human hand.

The eagle’s eyes are very large (in proportion as if we had eyes as big as oranges), a huge concentration of cones in the retina that provides a high resolution and the ability to notice the slightest movement in its field of view. The eagle has also a very wide visual field (about 1/3 of the human’s), thanks to the front-side position of the eyes, that at the same time allows a binocular vision on about half of the total field of vision.

It can dive at 200 km per hour in freezing temperatures of -20 ° C or preying moving animals swooping in on them through bushes and branches. For this, like all birds of prey, the eye is protected by a prominent brow ridge and a whitish nictitating and semitransparent membrane, that is beaten by the bird (from front to back) to moisten the eye or it is used during potentially dangerous situations for the eye itself, such as the catch prey or also, at times, while it rips the prey hair or breaks its bones.