The Birds

Bittern (Botarus stellaris) perfectly camouflaged in the reed beds. (Photo I. Fossa)

     This group is well represented with a great many both resident and migratory birds. Two of the water birds seen on Santa Croce Lake during the Autumn migration are the rare black throated diver (Gavia arctica) and red throated diver (Gavia stellata); they are excellent swimmers and divers so feed almost entirely on the fish they catch underwater and their plumage is di-stinctive for the pure white underparts.
     The great crested grebe (Podiceps cristatus) is a common migratory species and has nested at Lake Santa Croce since the end of the 1980s. Its head and neck are decorated with a crest of feathers and collar. It is famous among ethologists for its dance-like courtship ceremonies which include a wedding gift – a small fish or piece of a marsh plant.
The bittern (Bottarus stellaris) and the little bittern (Ixobrychus minutus) are perfectly camouflaged in the reed beds by the Lake, remaining quite still and upright with their beak pointing upwards. They are migrants at Lake Santa Croce, but the little bittern has nested there.
     The heron (Ardea cinerea) is quite common along the Piave river and its tributaries; it is a wading bird with long legs, recognisable by its slow flight when it holds its neck bent back and legs outstretched towards its tail. A few pairs nest in the high beeches along the eastern side of Arsiè lake.
     The cormorant (Phalacrocorax carbo) is a fishing bird with a hooked beak and eats only fish. It was seen for the first time at Lake Santa Croce 20 years ago and since then has become increasingly common in the area.
     Migratory ducks are also frequent and are notable for their sexual dimorphism, the males having more colourful plumage for most of the year. Surface feeding ducks that live in shallow water, do not dive and spring into the air to take flight include the mallard (Anas platyrhynchos) with a dark green head and brown breast for the male, and the garganey (Anas querquedula) whose male has a white streak on a brown head. Diving ducks like deep water where they dive for food and they patter along the surface noisily as they take to the air. They include the tufted duck (Aythya fuligula) whose male has an occipital crest and is completely black except for white flanks, the pochard (Aythya ferina) with a dark chestnut head and neck, pale grey body and black under parts, and the golden eye (Bucephala clangula) whose male has a large round white spot in front of its eye.
     The Accipiter family includes most of the day-time raptors, birds of prey with sharp claws to seize their victims and hooked beaks to tear them apart. In this group the female is often larger than the male. In flight they are seen soaring on rising warm air currents, their keen sight used for identifying their prey.
     The largest raptor, of which there are about thirty pairs living in the higher, rocky mountains of Belluno area, is the golden eagle (Aquila chrysaetos). The buzzard (Buteo buteo) is smaller and quite common, usually easy to see and hear as it circles over open spaces. The goshawk (Accipiter gentilis) is found in forested areas where it mainly hunts birds. The black kite (Milvus migrans) nests in few parts of the Belluno area, preferring to live near water. The Falconidae include the kestrel (Falco tinnunculus), somewhat smaller than the raptors previously described, recognisable by its swooping flight and curious hovering position with outstretched wings.
     The Tetraonidae or grouse family are chicken-like birds, sometimes with feathery feet, which live in high mountain woods, scrub and pastures. In this group there is notable sexual dimorphism: the females are well camouflaged, while the males have bright plumage and obvious red wattles. Having limited flying abilities, when threatened these birds hide in the undergrowth and only take flight at the last moment. Their courting ritual is quite elaborate with the males displaying themselves in a kind of arena. The capercaillie (Tetrao urogallus) has a large fan-like tail and dark greenish black plumage. The black grouse (Lyrurus tetrix) male (also known as the mountain pheasant) has a beautiful lyre-shaped tail, white underneath, and black plumage with blue-green highlights. The ptarmigan (Lagopus mutus) is known for its pure white winter plumage which camouflages it on snow covered ground.
     There are many species of the Strigidae or owl family living locally in both natural environments and places inhabited by people. Their noiseless flight is assisted by the fine down which covers the tips of their wings and they have forward-facing eyes which see well in the dark. They have powerful claws to catch their prey – usually small mammals – and a hooked bill to tear it up. They regurgitate pellets, usually dropped under where they roost. The eagle owl (Bubo bubo) is the largest European owl and quite rare; it has prominent ear tufts and can even catch hare, fox cubs and young deer. The tawny owl (Strix aluco) is more common; it lives in woods, parks and gardens, hunting small birds and mammals. The barn owl (Tyto alba), with its heart-shaped face may nest in attics and bell towers, eating even shrews which are usually scorned by other predators. The little owl (Athene noctua) lives in isolated trees and open fields, catching insects, mice and small birds; if surprised in day-time it bobs and bows its head in alarm.
     Many species of Picidae or woodpeckers live in gardens, parks, isolated trees and woods. Wood-boring birds, they are specialised in catching larva living in trees.They have strong feet with 2 toes in the front and 2 in the rear, short, stiff tails which act as props in climbing tree trunks; they are armed with pointed bills and long, sticky tongues. Their nests are artfully dug into tree trunks with several feeding holes and their drumming on the wood is often heard. The black woodpecker (Dryocopus martius) is the largest European species and lives in mature woodland, nesting in old trees. The green woodpecker (Picus viridis) also lives in parks and gardens and it can be recognised by its loud, ringing laugh. The most common is the great spotted woodpecker (Dendropocus major) which is capable of cracking hazel nuts and drums on dead branches.
     The Corvidae or crow family is here represented by 2 species, the carrion crow (Corvus corone) and the hooded crow (Corvus cornix). The former lives in west-central Europe from Italy to Spain, the latter from central Europe, including Italy, to the east towards Asia. The two species meet along a corridor 10 – 100 kilometres wide which includes the median part of the Alps, giving place to fertile hybrids. The raven (Corvux corax) lives in the mountains and may even catch hares, while the alpine chough (Pyrrhocorax graculus) is the undisputed acrobat of the rocks, even above 3,000 metres. Another common occupant of our woods is the jay (Garrulus glandarius), easy to recognise with its blue-barred wing coverts and raucous caw.

Capercaillie (Tetrao urogallus). In the mating season the male sings in a “wedding pose” to call the females. (Photo I. Fossa)

The Morphology of Birds
     Birds are vertebrate animals with a constant body temperature and their body is covered with feathers. These grow directly out of the skin, the plumage feathers covering the body and helping to keep its temperature constant, while the wing feathers are designed for flight. Both types of feather are periodically renewed in the spring/autumn moult. A greasy substance secreted by a gland above the tail makes them waterproof.
     Birds have a relatively light weight skeleton with pneumatic, that is hollow, bones which contain air sacs connected directly to the lungs as part of the respiratory system.
     The forelimbs have been transformed into wings while the hind ones are used for movement on land and in water.
The bird’s beak is used for holding, digging and for breaking up food; it is a very versatile organ, having many forms, depending on the type of food the bird eats. The most well developed senses are sight which is better than humans’, and hearing which helps nocturnal predators localise the noise of their prey at a distance.
     Birds are oviparous, that is they lay eggs. They reproduce in spring after courting and choosing a nesting site; after the eggs have been laid and hatched the chicks are looked after by their parents.