Odd Yellow Bittern

posted in: Morphology-Develop. | 0

“In July 2012 I posted an odd Yellow Bittern (Ixobrychus sinensis) from Kampar, Perak with pale pink plumage and pink at base of the bill. I considered at the time if it was a male with some mild leucism.

“Today I saw a similar Yellow Bittern. Processing the images does not do them justice as in the field the bird is pale pink and the striking feature is the extensive pink-red at the proximal half of the bill. The legs did not appear red.

1. My initial impression in the field was an immature male. There is a faint black cap and an adult male was in ‘attendance’ and appeared to be caring for this bird. The neck and breast streaks could be residual from the juvenile state and are only prominent after picture processing (contrast). In addition the bird was easily approached.

2. On reviewing the images at home I am more uncertain and now also considering a female in breeding plumage. The bright pink bill and attending adult male suggests that possibility.

3. Although not reported, it could be a colour variant.

a. When doing a literature search I came across Yuji Sawara from the Japan Bird Research Association who, in a Bird Research News article on the yellow Bittern (Vol.10 No.1, 2013), states that ‘The base of the bill turns red in the breeding season, which is more noticeable in the male’ (article available HERE).

b. See also my comments on male breeding plumage HERE.

“My final personal opinion is an adult female in breeding plumage.

“Appreciate opinions.”

Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
26th May 2018

Location: Tambun Interior, Ipoh, Perak, Malaysia
Habitat: Ex-mining pools with limestone hills and “wet-lands”

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