Since 1998 a pair of resident Oriental Honey Buzzard (Pernis ptilorhyncus torquatus) in the Royal Perak Golf Club, Ipoh, Malaysia, has been coming back to nest yearly (1, 2). Most of the time they produced one chick only but twice they produced and unsuccessfully attempted to raise two chicks.
The first attempt was the October 2001-March 2002 nesting. One of the two chicks died while still covered with white down. The other was found dead at the foot of the nest tree just days before fledging. The second attempt at raising two chicks was the November 2004-March 2005 nesting. Here, one of the fledglings was run over by a vehicle not long after fledging while the second fledgling disappeared and was never seen again during subsequent visits.
The resident pair returned to the golf course on 1st November 2005 and built their nest from 3rd November-13th December 2005. Nest foundations were built on three different tembusu trees (Fagraea fragrans) before the pair finally selected their nest location.
Copulation was observed from 26th November 2005 onwards. On the 5th and 13th December 2005, the male thwarted attempts by a pair of Crested Goshawk (Accipiter trivirgatus) to build a nest in a nearby tembusu tree.
On 17th December 2005, laying of egg(s) or incubation commenced. The male brought food to the female who remained in the nest all the time. By 18th December 2005, laying of eggs was assumed completed as the male was seen sitting in the nest. The very next day, eight to nine Large-billed Crows (Corvus macrorhynchus) launched an unsuccessful attack on the nest in an attempt to force the female to vacate and expose the egg(s).
Initially, on 30th January 2006, one chick about 7-9 days old in fluffy white down was sighted in the nest but on 6th February it was confirmed that there were actually two chicks.
The chicks were guarded all the time until they were about 12-14 days old when the female started to leave them on their own in the nest for short periods for the first time. At 32-34 days old, the chicks were generally left by themselves in the nest while the female stood watch from nearby trees. As similarly noted on previous observations, the pair copulated again while still caring for the young in the nest.
The chicks were fed with honeycomb and meat, provided for initially by the male. The female only provided food later. At 41-43 days old, the chicks were able to tear the honeycomb and meat into smaller pieced in order to swallow them.
On 10th March, at 46-48 days old, one of the chicks fledged but continued to roost in the nest for the next five days. The other chick fledged three days later, to also return to roost during the next four days.
After the chicks had fledged, the adults continued to drop off food in the nest until 13th April. For three weeks after fledging, the juveniles remained within 40 m of the nest tree and thereafter started to explore other parts of the golf course.
On the morning of 20th March, the adult pair each brought back a big piece of honeycomb and dropped them in the nest. Both the juveniles flew back to the nest and were observed tearing up the honeycomb with their bill and claws and then eating whole pieces of honeycomb. Jeyarajasingam & Pearson (1999) states that Oriental Honey Buzzards principally eat bee and wasp larvae but our observations that day revealed that they eat the honeycomb too.
Other food items brought back or fed to the fledglings included a young bird. On 30th March, Connie Khoo observed the adult female raiding the nest of an unidentified bird. She raided the nest three times, each time carrying out an egg with its bill to feed to one of the juveniles which swallowed the egg whole. It was noted that the juveniles partially depended on the adults for food 34 days after fledging.
On 13th April, Connie saw one of the juveniles dived from its perch on a high tree into a lower tree in which small birds were feeding/perching. It did not succeed in catching any and flew back to the same perch. It tried again before finally succeeding on its fourth attempt in catching and eating either a Eurasian Tree-Sparrow (Passer montanus) or sunbird.
Another observation made was that the adult Oriental Honey Buzzard have three types of calls. Previously, two calls were identified: a string of notes and a short call heard given out by the male during the 9th nesting when bringing food to the fledged juvenile. This season, a third type of call was heard given by the female which sounded like the “pee..ooh” call of the juvenile but shorter and with a deeper tone.
On 28th March, Connie again saw one of the juveniles peeling bark from the branches of a tree. Later it was seen swinging upside down on a branch before perching upright and then swinging upside down again. This went on for 20 minutes and was probably a form of “play-exercise” to strengthen its leg muscles and grip. Continued sighting of both the healthy-looking juveniles around the golf course on 19th April 2006 was a reassuring sight.
Breeding chronology for this season:
Nest building to 1st juvenile fledging: 127-128 days
Incubation to 1st juvenile fledging: 83-84 days
Incubation to hatching: 35-36 days (previously 42-47 days)
Hatching to fledging: 46-48 days
Input by Chiu Sein Chiong who wishes to thank Connie Khoo Siew Yoong for her patience in spending many hours observing and taking photographic records of the juveniles during the post-fledging period. Her contribution has resulted in new data being obtained. I also wish to thank Ooi Beng Yean, Cheang Kum Seng, Dr. Chan Kai Soon and Susan Cheong Suit Kuen for their participation in the observations and for taking photographic and video records.
Images from top: male Oriental Honey Buzzard, chicks, 7.5 weeks old juvenile (Chiu Sein Chiong) and juvenile (KC Tsang).
The above was first published in 2006 – Chiu, S.C. 2006. Oriental Honey Buzzards Succeed on Third Attempt at Raising Two Chicks. Suara Enggang (2): 15-16, 18.
Jeyarajasingam, A. & Pearson, A. (1999). A Field Guide to the Birds of West Malaysia and Singapore, Oxford University Press, UK.