Tag Archives: tweeddale morph

Tweeddale morph? Origins of the name for a uniquely plumaged Oriental Honey Buzzard (Pernis ptilorhyncus)

stray feathers jou 10 1887 hume_0544

19th century painting of “Pernis tweeddalii” by J. G. Keulemans

This post was triggered by an avid birder who asked the above question.

In the late 19th century, an Oriental Honey Buzzard Pernis ptilorhyncus with an (until then) never seen before blackish-and-white plumage was collected in the southeast of Sumatra, Indonesia. This specimen was described by British ornithologist Arthur Hay in 1877, under Pernis ptilorhyncus, apparently hesitating to separate it from the very variable Oriental Honey Buzzard.

Subsequently, another two specimens of similar plumage were collected, and the distinct plumage of these birds led ornithologists to treat them as a new species of Honey Buzzard. In 1880, this new species was christened Pernis tweeddalii, in honour of Arthur Hay, who was also known as Lord Tweeddale.

Along the way, it was lumped back into Oriental Honey Buzzard Pernis ptilorhyncus as it breeds with the normal brownish-plumaged OHBs resident in the tropics. Therein lies the origin of the name “Tweeddale morph” of the torquatus subspecies of the OHB.  

Singapore Raptor Report – Early Autumn Migration, July-September 2020 

PF, ernesti, 260920, Marina East Drive, Fryap, crop

ernesti Peregrine Falcon, note the dark ‘helmet’ and dense barring on underparts, Marina East Drive, 26 September 2020, by Francis Yap

A total of 67 observations were made for the Oriental Honey Buzzards, the highest numbers ever during the July to September period : 17 in July, 15 in August and 35 in September. Notably, all the honey buzzards photographed were sub-adults, right up to end September, suggesting that all the honey buzzards were over-summering birds. Over the 3-month period, moult of the primaries (feathers) progressed steadily and symmetrically on the wings, for the birds photographed. In July, the honey buzzards had 4-5 new primaries; in August, they had 5-6 new primaries; and in September they had 6-7 new primaries. While the moult in primaries was consistent between individuals, the moult for secondaries and tail feathers varied.

OHB,-190720,-PRP,-Ko-Engwee,-label

An over-summering sub-adult male OHB on 19 July 2020 showing symmetrical moult of the primaries on both wings, 4 new primaries (P1-P4), P5 missing, and old P6-P10, at Pasir Ris Park, by Ko Engwee

OHB,-080820,-Holland-Plain,-Angie-Cheong,-label,-date

An over-summering sub-adult male OHB on 8 August 2020 showing symmetrical moult of the primaries on both wings, 5 new primaries (P1-P5), P6 partly grown & obscured, and old P7-P10, at Holland Plain, by Angie Cheong

OHB,-270920,-PRP,-Saravanan,-label,-date

An over-summering sub-adult female OHB on 27 September 2020 showing symmetrical moult of the primaries on both wings, 6 new primaries (P1-P6), new P7 partly regrown, P8 missing, and old P9-P10, at Pasir Ris Park, by Saravanan Krishnamurthy.

Three torquatus Oriental Honey Buzzards were recorded – one photographed at Pasir Ris Park on 11 July by Chung Wah; one photographed at Changi in August by Wang HM; and a tweeddale morph photographed at Jurong Lake Gardens on 5 September by Chan Kumchun.

OHB, posted 050920, JLG, Chan Kumchun

A torquatus tweeddale morph Oriental Honey Buzzard, Jurong Lake Gardens, 5 September 2020, by Chan Kumchun

A total of 20 Japanese Sparrowhawks were recorded in September, with the first arrival on 18 September. The only record for the Chinese Sparrowhawk was a male at Jelutong Tower on 30 September.

Three Western Ospreys were recorded, one at Seletar Reservoir area, another at Sungei Buloh – Neo Tiew area and the last one at Chek Jawa, Pulau Ubin.

Three Peregrine Falcons were recorded – a probable ernesti at Pulau Ubin on 5 July, far and high up a pylon tower, by Martin Kennewell; an adult ernesti feeding on a bird at Jurong Lake Gardens on 12 September, by Kok M Lee; and an adult male ernesti at Marina East Drive on 26 September by Francis Yap, the East Coast Park sighting by Mike Hooper on the same day may be of the same individual.

For the resident raptors, seven diurnal species were recorded. Apart from the usual ones, there were records of the rare Crested Serpent Eagle at Pulau Ubin on 5 & 12 July; Pasir Ris Park on 17 September; Malcolm Park on 23 September; and Kent Ridge Park on 30 September.

CGH, 260920, PRP, Derrick Wong 2

Crested Goshawk caught a lizard, Pasir Ris Park, 26 September 2020, by Derrick Wong

There were nesting-related records for 3 species of diurnal raptors. A pair of Black-winged Kites were nest-building on 16 August, with mating observed on 12 September, at Seletar. At Neo Tiew side, another pair of Black-winged Kites were observed mating on 29 August. For the White-bellied Sea Eagle, 2 fledglings were out of the nest at Fort Canning on 11 July; another 2 fledglings at Sungei Buloh Wetland Reserve were in and around the nest on 26 July, and the adults were observed mating on 19 September; at Kent Ridge Park, 1 adult was flying with a branch on 24 September, presumably to build a nest.

At Pasir Ris Park in September, a pair of Crested Goshawks were re-using their old nest (their nesting attempt in March appear to have failed), while another at West Coast Park was carrying a stick on 12 September, presumably for nest-building. The prey items of the Pasir Ris Crested Goshawks included Changeable Lizards, Javan Mynas, feral junglefowl chicks, rats, and on 25 September, a young water monitor lizard.

For nocturnal raptors, a pair of Buffy Fish Owls at Pasir Ris Park were observed mating on 9 September; another 2 Buffy Fish Owls were found together at Changi Business Park; while an Eastern Barn Owl made a 1-day show at Elias Road on 27 September.

For a pdf version with more details, please click Singapore Raptor Report, Early Autumn Migration, Jul-Sep 2020

Compiled by Tan Gim Cheong

Many thanks to everyone for their records and to Francis Yap, Ko Engwee, Angie Cheong, Saravanan Krishnamurthy, Chan Kumchun, and Derrick Wong for the use of their photos.