Student Magazine > Environmental > Environmental Issue 1 > Raptors and Kingfishers Skip Navigation Links Login

Raptors and Kingfishers

Barbara Bacci



GRIFFON VULTURE

The Duratón River Canyon Natural Park is situated north of Madrid, Spain, in the province of Castilla and León. The winding path of the river Duratón flows for 25 km within the Park. The river has excavated the surrounding limestone walls which, in places, measure over 70 metres. The area comprises 4 different habitats: Dry plateau, rocky ledges, riverbank forest, and  pine groves on the sand. The rocky ledges separate the dry plateau from the humidity of the river. Due to the poor soil cover, the steep gradient of the slope and the high pH of the soil, only specific rupicolous vegetation grows on these cliffs. It is in the habitat that the Griffon vulture, Gyps fulvus, makes its home.
Many more raptors live and reproduce in the area: Egyptian vulture, Neophron pernopterus, Golden eagle, Aquila chrysaetos, Peregrine falcon, Falco peregrinus, and in the pine forest zones: goshawk, Accipiter gentilis, black kite, Milvus migrans, short-toed eagle, Cyrcaetus gallicus.
 
Griffon Vulture. Pencil on paper

The Griffon Vulture is a large Old World vulture, occurring throughout Southern Europe and parts of Northern Africa and Asia. In flight, it can be identified by its broad wings with long “fingers” and a short, rounded tail. When light conditions are good, flight and tail feathers appear dark, while wing-coverts and body are light coloured. It flies with its neck folded.
Griffon vultures can be seen soaring for miles around the park – in fact, they are present in most of Spain, including the outskirts of the capital, Madrid. They can soar for 6 and more hours and reach heights of over 3000 metres.
Griffons feed exclusively on carrion and rely on seeing other birds feeding to find food. Apparently, this is because they have a poor sense of smell. The bald head allows the bird to feed on decaying meat without picking up harmful bacteria and dirt.
Some areas within the park offer great views of the ledges where Griffons have their large colonies. I visited the park  in November, during breeding season. The birds were displaying on the cliff faces, making a variety of sounds, mostly hissing and grunting. It is thought pairs mate for life. In December-January, the female lays one egg, which both parents take turns in incubating for about 50 days. Young are born covered with pale down and take 3-4 months to fledge.


COMMON KINGFISHER

The European, or Common Kingfisher, Alcedo atthis, is a small river kingfisher which inhabits fresh water areas in Europe, Asia and Africa. With the exception of those places where the water freezes during the cold season, it is a resident.
It is a resident bird on the Tiber, with some individuals present in the city centre. It’s a territorial bird, so every individual more or less occupies a certain area and thus it will always be observed alone. “Observed” in the case of the Kingfisher is a big word: Although it’s brightly coloured it cannot be easily spotted. Usually, I perceive it, or guess his presence: A familiar fluttering of wings close to the water surface, a direct flight, a glimpse of iridescent blues and greens. It generally perches on a low branch over the water, ready for its vertical plunge dive to catch a small fish. Kingfishers sometimes hover over the water before diving in. They have very good eyesight and polarising filters to cut out water reflection, but during the plunge the eyes are protected by a membrane, so prey is caught by touch alone.
They take their prey back on a branch where they whack it to death before swallowing it head first. They feed mostly on small fish but will also eat prawns, crabs and mudskippers.
The Kingfisher is a small, compact bird, with short legs and tail, a large head and a very long and thick bill.
It’s a shy animal and when I walk along the water edge I sometimes see him flying away from me, just over surface of the water. Its flight is fast and the short rounded wings whirr so rapidly they appear like a blur, but the metallic blue of the upperparts and the green reflections on the head and the wings are visible.


SPARROWHAWK

Slatty’s Bridge is one of the important ornithological sites in the Cork bird trail (Co Cork, Ireland). Situated on the northern most edge of Cork Harbour, the area comprises two different habitats: Estuarine mudflats on one side of the bridge and a brackish lake on the other. A variety of waders and waterfowl feed or inhabit the area. Surrounding the site are woodlands and cultivated fields, the kind of environment where sparrowhawks can be observed hunting.
The Sparrowhawk, Accipiter nisus, is a small diurnal raptor, belonging to the family Accipitridae. It has short broad wings and a long tail which enable him to manoeuvre through trees. I have seen Sparrowhawks pursue their prey flying at low level over the ground in the reedbeds, although usually I see them soaring over woods or fields looking for prey.
Sparrowhawks are becoming more common in urban areas, such as city parks or private gardens. This is the photo we took of a sparrowhawk plucking its kill in a garden, in Cork, not far from Slatty’s Bridge. Likely, it had killed one of the songbirds regularly feeding in the garden.
Sparrowhawks exhibit reverse sexual size dimorphism. Both sexes have barred underparts, the male being tinged with red with a bluish-grey back; females have brown upperparts and dark barring underneath. I believe this is a female.
 

 


KITES, SPARROWHAWKS, KESTRELS, MONTAGU’S HARRIER

The Tolfa Mountains are a hilly mass reaching 638 metres above sea level, situated in north-west Lazio, close to the sea. These ranges formed following a series of volcanic eruptions in the Quaternary period and are now covered with coppice or grazing land. The flora varies from the lentisk, arbutus berry, cork and holm-oak of the lower levels closer to the sea, to the beech, hornbeam and chestnut trees higher up.
Many mammals such as wildcat, otter, wolf, wild boar, martens, squirrels and various rodents inhabit the area. There are also many bird species, amongst which a variety of raptors, the red kite and the eagle owl amongst others.
On a good morning walk in these mountains, it is possible to see a quite a variety of birds of prey. On just such a morning, we were able to observe red kites, kestrels, sparrowhawks, and one Montagu’s harrier.
Watching and identifying birds of prey is all about recognizing their body, wing and tail shapes; colour is secondary due to distance, as birds are often very far, and poor conditions, such as watching birds against sun glare.
The red kite, Milvus milvus, is a large bird with reddish-brown plumage, angled, “fingered” wings and a deeply forked tail. The white primary feathers contrast with the black tips and dark secondaries. Three birds circled over our heads long enough to study the various details. Sexes are similar.
The Sparrowhawk and the Kestrel are much smaller, almost the same size, and both have a long, rectangular tail, but the Kestrel has long, narrow, pointed wings. In addition, it is quite common to see the Kestrel preying by hovering, keeping still in the same spot. Only the Kestrel and the Lesser Kestrel adopt this curious hunting technique, which in Italian is referred to as doing “the holy spirit”. Although this is a costly technique in terms of energy requirements, it makes hunting more successful and is employed more often during breeding, when the birds need more food for the young. On this particular morning, the Kestrel and the Sparrowhawk attemps at hunting were constantly interrupted by hooded crows mobbing and chasing them.
Just before leaving the area, we saw a Montagu’s Harrier, Circus pygargus. With a wingspan of no more than 115 cm. this harrier is a littler smaller than the Marsh Harrier I see more often in the marshes closer to the sea. Sexual dimorphism is evident in this species. The male has light grey plumage with black wingtips, whereas the female is similar to Pallid and Hen Harriers. A characteristic of the Montagu’s Harrier, however, are the black bars along the secondaries, visible both above and below the wing, as well as chestnut streaks on the underparts. A melanistic form, with darker birds, can be seen.
 
                 Coloured pencil and ink.


OWLS

I have some first hand experience with nocturnal predatory birds because I have been volunteering at a local wildlife rescue centre for years. The species we deal with more often are Little Owls, Barn Owls, Tawny Owls and Long-Eared Owls, although occasionally we see an Eagle Owl or a Scops Owl. Generally, we get young birds who have just left the nest and are getting around but are still unable to fly. When people see such a young bird they think it has gotten lost or has been abandoned and they “rescue” it. In fact, the parents are just nearby and will continue looking for the chick for a day or two, which makes it possible, in some cases, to return the young bird to the care of its own parents. These birds have to learn to know their own environment and have to develop hunting skill, crucial factors which makes fostering them an arduous task. When it does happen, however, we keep the young birds as quiet as possible, limiting all contacts with humans to minimize the chance of imprinting. Barn owls and other owls hiss and make snapping sounds by clicking their tongue when scared and distressed. Chicks react in this way more often than adults.
The younger birds are fed liver and kidneys, which are highly nutritious and easily digested. Fledglings are fed day-old chicks or lab mice cut up in small pieces. Once they are able to eat by themselves, they are moved to an aviary where they hopefully will learn to fend for themselves by watching the adults (recovering individuals which can be returned to the wild).
Like other birds, owls can’t chew but, unlike other birds, they lack a crop. The food goes directly into the proventriculus, where the digestive process is initiated, and then passes through the gizzard, where insoluble items are separated and held back. While the soft contents in the food continue through the rest of the digestive system, the indigestible parts such as bones, fur and feathers, are compressed into a pellet the same shape as the gizzard. The pellet moves back to the proventriculus and a few hours later it is regurgitated.
Compared to raptors hunting during the day, night predators are very calm in the presence of humans and can be handled without too much fear of being pecked or attacked.
However, all raptors can become very tame. I have seen hawks raised with hens quietly perching and “begging” to be petted or fed. These animals have become irrecoverable and need human care to be able to live.
Some of the animals we have were once “pets” somebody grew tired of. I find it a curious thing that many Little Owls which have known captivity tend to be far more aggressive than the wilder ones.



SPANISH IMPERIAL EAGLE

Eagles are large raptors which, aside a few exceptions, inhabit the Old World. They belong to the order Falconiformes, family Accipitridae, and are subdivided into various genera. The genus Aquila comprises 15 species, amongst which is the Spanish Imperial Eagle, Aquila adalberti.
Closely related to the Imperial Eagle, this species is quite rare, sedentary, and occurs only in South and West of Spain and Portugal, where it inhabits cork oak forests, plains and hills in central Spain, flood plains and dunes in the Guadalquivir marshes, but also high mountain areas in the Sistema Central.
It differs from the Imperial Eagle in having a white leading edge of wing above and below; the shoulder patches are more extensive and furtherforward. Flight feathers are somewhat darker and less barred. The inner portion of the tail is a paler grey, and it is not barred. It has a slightly stronger bill and cream head and neck. Juveniles are more rufous-brown and acquire a full adult plumage at six years of age.
Spanish Imperial eagles are highly territorial and will allow only immatures of their own species to enter. They build their nests in tall oak or pine trees, and have various nests within their own territories, which they use in turns. Courting begins in January and in March pairs have been formed. They abhor human presence and will abandon their clutch if molested. Both male and female incubate the eggs – 2 to 4 – for 43 days and cover them with small branches when they leave. They both raise the young, tearing prey apart for them until they can hunt for themselves. The chicks develop their first plumage within 35 days and start leaving the nest at two months of age. Generally both chicks reach adulthood, but when food is scarce they do practice Cainism.
Although it can hunt a variety of small animals (rodents and birds), the Imperial Eagle feeds mostly on rabbits and therefore its population is influenced by the abundance and distribution of prey in the area. The Spanish Imperial eagle is an endangered species and was made more vulnerable by reforestation: Unlike the eucalyptus and pine plantations, the original oak forests were rabbit rich and largely left alone by humans. The power lines surrounding the park of Doñana represent yet another problem and are the cause of death of many birds, especially juvenile females. Larger than males, the young birds are more likely to touch a live wire while perched on a metal supporting pylon. A possible although costly solution could be burying transmission lines. Finally, removing chicks to foster nests, avoiding their death by Cainism, could help population growth.


ELEONORA’S FALCON

Order: Falconiformes; Family: Falconidae; Genus: Falco; Species: Falco eleonorae

Eleonora’s Falcon is named after a Sardinian princess of the fourteenth century, Eleonora d’Arborea, who passed laws protecting falcons.
This medium sized falcon is about 36 to 42 cm in length, with a wingspan of 87-104 cm. It’s a slim bird, with long, pointed wings and a long tail. It’s similar to a hobby or a male peregrine falcon. It occurs in two different colour morphs: a light one, chestnut-red with longitudinal barring, the most usual, and a dark phase, almost black. A gregarious bird it can be identified by its typical call: a grating “kye-kye-kye-kye”.
It’s a migrant, and winters in Madagascar to returns to the Mediterranean in April-May. Eleonora’s falcon is the only European bird to breed in autumn. It breeds on rocky islands in the Mediterranean, especially Greece, and on coastal cliffs in north-west Africa in colonies of up to 200 pairs.
Until July, the falcon feeds on insects such as grasshoppers, beetles and moths. When the young hatch in late August, the falcon switches its diet to birds and relies on the massive front of migratory birds travelling south to raise its young. It hunts in groups. The young set off for the migrating journey a mere two weeks after fledging, in late October. When they reach Madagascar, the falcons resume their insectivorous diet.
Although it is not considered a threatened species, there is concern for the Eleonora’s falcon. The breeding sites the bird uses are few and there are threats such as egg-collecting, illegal hunting, human disturbance, habitat degradation. Given that about 70% of the falcon’s global population breeds in the Greek archipelago, Greece  is implementing a plan for the long-term conservation of what is its most important bird species.


LAMMERGEIER

Order: Falconiformes; Family: Accipitridae; Genus: Gypaetus; Species: Gypaetus barbatus

The Lammergeier, also known as Bearded Vulture is the only member of the genus Gypaetus. It’s a very large, broad winged raptor, 105 to 125 cm in length, with a wingspan of 235 to 275 cm. Pliny had named him Ossifragus, which means Bone Breaker, because of the bird’s peculiar way of breaking bones: By dropping them from a height of up to 200 feet, usually on slabs of rocks. First, the Lammergeier approaches the slab downwind, holding the bone in its feet, then it dives and dips in flight to increase its velocity and finally releases the bone. The bird watches the bone land and then spirals down towards the scattered bone fragments to eat them. Like that of other carrion birds, its digestive system presents conditions of extreme acidity, capable of dissolving bone calcium.
Aside from bones, the Lammergeier feeds on freshly killed animals, carrion and on live turtles, which it too drops on rocks to open the shell.
It inhabits inaccessible high mountains areas (usually between 4,000 to 10,000 feet, but can be found above the 15,000 foot range) of Europe, Eastern and Southern Africa, India and Tibet. It breeds on steep cliffs, from late January to July. It generally lays two eggs which hatch after an incubation of about two months.
Adults have yellowish-buff body and head – unlike other vulture, the Lammergeir does not have a bald head – and a dark band of feathers. The pale body, which can appear rusty in colour due to the sand-baths, contrasts with the dark underwings. The upperparts are lead-grey with pale feather shafts. In the young, the dull grey body contrasts with the dark grey head. The upperparts are not uniformly dark but variegated; mantle, rump and some wing-coverts are light. It acquires the adult plumage at about 5 years of age. It has very large and strong feet and claws and a very sharp bill for ripping and tearing flesh.
In flight, it’s identifiable by the long, narrow and pointed wings and the long wedge-shaped tail. It soars and glides for hours at a time on mountainsides.


COMMON BARN OWL

Order: Strigiformes; Family: Tytonidae; Genus: Tyto; Species: Tyto alba

 
Barn owls. The male hunts, while the females broods the eggs and raises the chicks. Mixed Media.


Strigiformes are divided into two families: Tytonidae, comprising barn owls and related species, and Strigidae, or Typical Owls.
Although already known, the Barn Owl was first officially described in 1769 by an Italian naturalist, Giovanni Scopoli. Its name, alba, refers to its predominant colour, white. It is a medium sized bird, 33-39 cm in length, with a wingspan of 80-90 cm. It has a slim body with long wings and long legs. The heart shaped facial disk is pale white with a brownish edge. The eyes are dark, the bill whitish and the feet yellowish to brownish. The plumage is very light in colour, the upperparts are light grey and present many dark lines and scattered pale spots, on the white underparts there may be a few black spots. There are buff markings on the wings and on the back. Juveniles are more densely spotted. The male is slightly smaller than the female and a little paler in colour. Different subspecies have different coloured underparts.
It has a slow and wavering, silent flight and lets he legs dangle while hovering. It’s a sedentary bird and occurs worldwide, except Antartica.
Barn owls adapt to different habitats but are more common in open woodlands, heaths and moors. farmlands, and villages close to fields. They like to roost in tree hollows, caves, out-buildings or thick foliage.
They hunt along the edges of woods, and specialise in hunting small ground mammals, such as voles, rats, shrews and mice, but can hunt  frogs, insects, lizards, and small birds. They hunt both from a perch or by searching for prey in open grassland.
Barn owls are nocturnal birds, but they will often hunt at dusk and dawn and can be seen flying in full daylight.
Barn Owls breed in response to food supply, and will breed rapidly in case of mouse plagues. When courting, males fly in circles near the nest tree calling out with a shrill repetitive twittering and short screeches. They usually nest in tree hollows, but can nest in old buildings, barn lofts and church steeples. The female lays from 3 to 6 or more eggs and incubates them for 30 to 34 days. The chicks, covered in white down, are brooded for 2 weeks. They take 50 to 55 days to fledge and often leave the nest before being fully able to fly. They remain close to the nest for about 2 weeks to learn hunting skills and later disperse from the area. They can breed at about 10 months.


KOOKABURRAS

 
 
Laughing Kookaburra. Guache on coloured paper.


Order: Coraciiformes; Family: Halcyonidae; Genus: Dacelo

Kingfishers are divided into 3 families: Alcenidae, river kingfishers, Halcyonidae (or Dacelonidae), tree kingfishers, and Cerylidae, water Kingfishers.
Kookaburras are terrestrial birds; like all kingfishers, they have a compact body, short neck, and short legs. The largest species, the Laughing Kookaburra, reaches about 45 cm in length. The bill is strong, rather long, pointed and black. The upperparts are dark brown, the under parts off-white and the wings mottled with grey. The tail is somewhat reddish and barred with black. A white band separates  the head from the body. A dark brown stripe goes over the eye.
There are 4 species: The Laughing Kookaburra and the Blue-winged Kookaburra both occur in the woodlands and open forests of Australia. The Rufous-bellied Kookaburra inhabits the rainforests of New Guinea, and the Spangled Kookaburra lives in New Guinea and on the Aru Islands.
Kookaburras have adapted to humans and can be found in the suburbs. If given a chance, they might steal from a barbecue!
They are carnivorous and feed on lizards, insects, and mice. They catch snakes, dropping them from a height to kill them, or which they batter senseless before swallowing them. They prey on ducklings and other chicks too.
Kookaburras live in small flocks and favour open woodland. They are territorial, monogamous, and nest in tree trunks, tree holes, and in termite nests, where they lay 2 to 4 white eggs. Both parents incubate the eggs for 25 days. The young are then fed by their parents for the first month in the nest, and for a further 40 days after leaving the nest.
At dusk and dawn, kookaburras roost in treetops and emit their loud call, similar to a human laugh. The Aborigines say that when the sun first rose a god, Bayame, asked the kookaburra to give out his call to wake up all of humanity, so that they should not miss the spectacular sunrise. It is the Aborigines who have given the kookaburra its name, taken from a word of the Wiradjuri people, guuguubarra, which sounds like their unique laughing call.


DIFFERENCES AND SIMILARITIES BETWEEN DIURNAL AND NOCTURNAL BIRDS OF PREY


Diurnal and nocturnal birds of prey are not strictly related, but they share the same environments and have adapted to similar conditions, and therefore present convergent evolutions traits, such as a hooked bill, keen eyesight, powerful talons, and cryptic plumage.
 

 

Keen eyesight and a hooked bill are necessary for hunting. Ink.

 Body part/behaviour  Diurnal birds of prey
  Nocturnal birds of prey
 They both capture live prey and need an acute sense of hearing.  Some diurnal raptors, like the Hen Harrier, also have a facial disk to enhance hearing.  Many owls have asymmetrically set ear openings, making each ear more sensitive to sounds coming from different directions. The facial disk directs sounds into the ear opening.
 Sight
    Large, forward sight with overlapping binocular fields of vision.
Some raptors have a central and a lateral fovea. Foveas have a much higher concentration of rods than humans, which means the birds visual resolution is better than ours.
Eagles and hawks have the largest and most elaborate pecten of all birds. Pecten is a folded tissue which supplies nutrients and oxygen throughout the vitreous humour of the eye. 
 Forward sight with overlapping binocular fields of vision. The eyes are very large and held in place by bony structures, the sclerotic rings. For this reason, owls cannot roll their eyes and make up for it by turning their head around and almost upside-down.

     
Flight 
 Falcons capture their prey in flight, by stooping; their pointed wings and aerodynamic structure allow them to reach a speed of 200 km/h.
Accipiters, like the Goshawk and the Sparrowhawk, hunt in woodlands, and use their narrow, falconlike tails and broad wings to manoeuvre quickly through the vegetation.
Soaring birds, such as hawks and vultures, can separate their long and narrow outer primaries to fly at a lower speed without stalling. Buteos have long, broad wings and tails for gliding and kiting.
Harriers have primaries bent upward to fly at low speed, and they hold their wings in a V position to gain stability.
 Owls have a silent flight. The primaries of owls have a comb-like leading edge. The air rushing over the surface of a flying bird creates turbulence, producing a gushing noise. The comb-like feather edge of owls breaks down the turbulence into little groups of micro-turbulences, muffling the sound made by the air.
 Feet 
 Diurnal raptors have 3 toes facing forward.
The Osprey has a toe he can point either forward or backward.
  Nocturnal raptors have 2 toes facing forward.
The Tawny Owl, like the Osprey, has a toe he can point either forward or backward.
 Behaviour  Reversed sexual size dimorphism, particularly evident in some species, such as the Sparrowhawk. One of the advantages of this trait is the use of different hunting areas.   Reversed sexual size dimorphism.