Sunday, March 29, 2020

Blyth’s Hawk Eagle Spizaetus alboniger (Blyth) 1845


Blyth’s Hawk Eagle Spizaetus alboniger (Blyth) 1845
Other Name: Black and White Hawk Eagle
Resident

Status and distribution
This species is found resident throughout Malaysia.

Description
Adult black and white distinctive. Up right crest distinctive. Underpart white with black streak on the breast and barred remaining lower part. Throat white with mesial streak black. Upperpart black sometimes appear dark brownish black on the wing. broader compare to terminal.
Barring below extend to thigh. Tail is diagnostic to this species where black terminal, pale subterminal

Some adult show pale white supercilium, which require further observation and study to see the relationship between age or sexes.

Identification of male and female plumage can be read in the post here.

Inflight wing shape typical of Hawk Eagle and black and white plumage are distinctive. Wing feather at leas 4 black band.

Juvenile very similar to Wallace’s Hawk Eagle. Mainly brown all over. See confusion species.

Juvenile (up to first year)
Very similar to Wallace’s Hawk Eagle. Overall rusty brown plumage. Crest always erect with circular nostril. Throat paler and thighed paler. Faced and cheeked rusty brown. Underpart of body rusty brown. Crown darker brown compare to body. Upperpart of body brown with pale tip on feather.
Tail band show only part currently differ from wallaces where terminal dark band slightly broader then subterminal pale band. Overall roughly 5 tail band can be seen.

Subadult
Heavily moulting on underpart. Tail show marking of adult. Underpart of body can be seen on thighed and vent and at least some part of the mid body. Breast streak at this age are still very little.

Moulting four years to adult. However every plumage require further documentation as this were poorly recorded.

Confusion Species
Highly confuseable depending on age to Wallace’s Hawk Eagle. Juvenile bird moult begin on thigh <= => wallaces on breast.
Differ greatly on the tail banding in adult. See description above <= => wallaces evenly devided tail band.

From Indomalayan Honey Buzzard tweedled morph, by crest always erect <= =>drop floopy in Honey Buzzard. Nostril shape which is circular <= => slit in honey buzzard. Position of leg and shape of head provide best clue to separation.

Geographical Variation
No other was recognize.

Behaviour
Many of this species behaviour are poorly recorded. Hunting are mainly in perching hunting method. Diet remain poorly recorded with one crow sighted on nest. Other are small mammals include species such as Low’s Squirrel Himalayan Stripe Squirrel. Reptile not identified in this country however lizard have been seen. This was further confirmed through Well’s 1990.

In regards to method use, it was believed to have been based on the habitat of which hunting in highland and lowland however this require further research. This however the bird never observed to hunt below canopy compare to Wallace’s which hunt and track prey below canopy.

Breeding photo and video see the topic of photo and video.

Habitat
In Peninsula Malaysia this species is seem mainly in submontane elevation however there is occasion where it wander lower such as the Lembah Bujang and Taiping Lake Garden. See nesting altitude. Seen up to 1,500m asl.
Other lowland forest include foot hill of Maxwell Hill. A lot of nest were also observed below 500m asl.

Breeding
Nesting poorly documented however recorded year round. Nest in in few location from Pahang, perak and kedah which has include incubation on February, August and September. Period observed including February to March, September to December. Eaglet with juvenile plumage at nest recorded in April, November and May. Juvenile hatch plumage recorded in March and May.
Tree were estimate at 40 meter high emergent at that location at the altitude of about 470m asl. 

Display behaviour non recorded. Copulating non recorded. Nest building and incubation period poorly recorded. Both male and female are seen in the nest. Only once there was a display observed in Perak which describe “One individual believe to be the male soar at very high altitude. The bird make a fast and agrresive stoop verticle downwards and lift itself up later to a perch. Anotehr individual believe to be a female was observed circling and observing nearby. Time of observation was 11am” There was no nest observed during this display.

Nesting tree selection usually on slope area and emergent tree. This with additional criteria of the location required a bare tree nearby of the approximately same high to the nest where perching bird can oversee the nest. Only one nest where it was observed both parent actively adding new fresh twig to the nest.

Nest in lower altitude. In sabah Smytheis 1999 Nest was location at 400m. No difference in P. Malaysia where nest were found in the same altitude. However nest was also found above 1200m asl in Genting Highland and Cameroon Highland.

Dependency period unknown. In all nest only one egg and one eaglet was raised.


Photo
Nest 1
Nest 2

Video
Nest 1
- Video 2 - Nestling at nest.
- Video 6 - Eaglet age Day 36-42
- Video 7 - Eaglet Day 40-46
- Video 12 - Eaglet at day 45-51
- Video 13 - Adult near nest
- Video 15 - Upclose day 51-57

Reference
Ben F.King & Edwards C.Dickson, 1989, A Field Guide To The Birds of South-East Asia, Collins, Grafton Street, London

Craig Robson, 2017, A Field Guide To The Birds of South-East Asia, Bloomsburry, London

Handbook to Birds of The World, Lynx Edicions, Bercolona, Collins, Grafton Street, London

Smythies B.E Revised by Davison G.W.H, 1999,  The Birds Of Borneo, Natural History Publication, Sabah Malaysia. (ISBN 983-812-028-6)

Susan Myers, 2009, A Field Guide To The Birds of Borneo, Talisman, Singapore

Boonsong Lekagul & Philip D.Round, 1991, A guide to the Birds of Thailand, Saha Karn Bhaet Co., Ltd Bangkok

David R Wells, 1999, Birds of The Thai Malay Peninsula Vol 1, Academic Press, London UK

James A. Eaton, Bas van Balen, Nick W. Brickle & Frank E. Rheindt, 2016,  Birds of the Indonesia Archipelago Greater Sundas and Wallacea, Lynx Edicion, Bercelona

James Fergusan Lee and David A Christie 2001, Raptors of The World, Christopher Helm, Great Britian (ISBN 0-618-12762-3)

Medway & David R Well 1976, The Birds of the Malay Peninsula Volume V: Conclusion and Survey of Every Species, Broadwaterpress, England



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