Crested Hawk-eagle

 

Crested Hawk-eagle

               Introduction of Crested Hawk-eagle

     The Crested Hawk-eagle (Scientific Name :Nisaetus cirrhatus), is a bird of prey belongs to the family Accipitridae. Previously,they were in the genus Spizaetus. But now they are separated and placed in Nisaetus.

                   How to identify Crested Hawk-eagle 

     The Crested hawk-eagle is a raptor. Length of this bird is about 60-82 cm. and wingspan from 100 to 160 cm (3 ft 3 in to 5 ft 3 in). It is a relatively slender forest eagle with some subspecies (especially limnaetus) being dimorphic giving the name of "Changeable". 

    Body of Crested Hawk-Eagle is slender.  Color of the body is normally brown above and white below with black streaks on throat, on breast and  on the undersides of the flight feathers and tail. There is a long narrow crest projecting behind the head. It has rather short wings, a quite long, thinly-barred tail and long feathered legs. Crested Hawk-Eagle tends to perch “bolt” upright,  When perched, their wings reach only about one-third to halfway down tail. Colors of eyes of adults are yellow to orange yellow, while those of the juvenile are grey-brown to pale greenish. Cere of adult are grey to pale greenish yellow and juveniles’ ceres are dull greyish. Feet of Crested hawk-eagle of all ages are yellow.  Male and female looks  alike. But female is larger than male. Head of  young Crested hawk-eagle's  varies from buff with white-tipped black crest  through entirely whitish, but almost always the young birds are spotted and streaked with black or dark brown about the rear crown and nape

    The species tends to fly with a fast agile flight, showing powerful shallow beats interspersed with glides on flat or bowed wings with their carpals well forward (above level of bill) and primaries swept back.

                     Distribution

    Crested hawk-eagle may be found anywhere from sea level to 2,200 m (7,200 ft) but mainly live below 1,500 m (4,900 ft).Crested hawk-eagle are found much in the Indian subcontinent and southeast Asia such as Sri Lanka,  southern Nepal and Bhutan east through Myanmar, Burma, western Laos, southern Vietnam, Cambodia, Thailand and peninsular Malaysia. In India, they are found almost continuously from the peninsular tip north to Rajasthan, Uttar Pradesh, Bihar and Odisha and Himalayan foothills (Garhwal to Assam)

Crested hawk-eagle on perched
(Photo by: Mrs Anu Kadri)

                    Habits and Habitats

    Natural habitats of this species are savannah woodland, cultivation with trees, timbered watercourses, tea plantations, forest villages and even suburban edge. Beyond these, they are  often found  into fairly open or less dense parts of undisturbed vast evergreen or deciduous forests. This species are primarily ambush predators who use concealing foliage to still-hunt from hidden branch or open branch with a leafy background, pouncing fast to take most of their prey on the ground.

                    Food

    The  Crested hawk-eagle have a slight preference for birds as their food, but  various mammals, reptiles and some other vertebrates are also in their food list.

                     Call

    The Crested hawk-eagle  is mainly silent but in breeding season it may readily call. Their calls are a form of high-pitched scream. The shrill ringing and loud call of the changeable hawk-eagle is various described in pattern of yeep-yip-yip-yip, rising kwip-kwip-kwip-kwee-ah and penetrating klee-leeuw . Ascending kri-kri-kri-kree-ah and kreeee-krit with much stress on the elongated first syllable are similar. From western birds from India and Sri Lanka, the call is a slightly different ki-ki-ki-ki-ki-ki-ki-keee, beginning short, rising in crescendo and ending in long, drawn-out scream.

                   Breeding and Nesting

     The Crested hawk-eagle is mainly solitary bird but form pair during breeding and often mate for life. Each pair engages in a courtship display.  This aerial display is usually engaged in by a male but sometimes the female or both members of the pair will engage in displays. Courtship often start with their wings and tail arched upwards in exaggerated poises. During the display, the shoot up vertically and nose-diving or stooping. They fly at each other doing a complete loop-the-loop turn in air. They often call loudly throughout the display.

     The breeding season of Crested hawk-eagles is from November to May in southern India, and from January–April in the more temperate climate of the Himalayan foothills. This species builds a large  nest with sticks.  Dimensions of their nest is 37 to 41 in.  and depth can range from 14 to 47 in.  Nests are lined with green leaves. Both male and female of the pair participate in building new nests and take part in repairs. Nests are often solidly built and resilient, more so than those of other medium-sized eagles, against high winds and monsoons. Crested hawk-eagles  build their nest usually at  height of 39 ft  82 ft in the crown or high fork of a large tree. Nests  are generally build  near a stream or near a ravine. But sometimes varies from deep forest to isolated trees on village edges also.

    Female lays only one egg.  The egg is coarse and glossless, mainly white but have sparely and faintly  blotched with light reddish. Egg sizes is 2.57 to 2.87 inch in height.  Mainly the female alone incubates the egg.  Estimated incubation period is  about 40 days. After the nestling hatches, the female will brood intensively for about 25 days.  After a couple weeks, prey is delivered to nearby branches rather than  to the nest and  the parents  encourage the young eaglet to come out of the nest. By 52 days of age, the eaglet is fully-grown but does not fledge until about 60–68 days.