Intermediate Egret breeding in Peninsular Malaysia [I]

“I was at a rural community visit and once it was finished (after lunch) decided to wander around this rural location (camera accompanies me on these rural visits). Came across an extensive egret breeding site with an excess of 500 birds (hard to estimate upper limit, muddy area and was in my work shoes/clothes). They were predominantly Little Egrets (Egretta garzetta) and Cattle Egrets (Bubulcus ibis) nesting together.

[above left shows a breeding adult at the nest; above right shows the breeding chest and back plumes]

“However there were a number of nesting/breeding Intermediate Egret (Mesophoyx intermedia intermedia). I say this cautiously as there has been no prior documentation of Intermediate Egrets nesting in the Peninsular.

“Features present in other white egrets during breeding that do support them in this ID:

Great Egret – legs usually red, purple-blue facial skin, diagnostic dagger behind eye, no chest plumes; Little Egret – yellow feet, purple-reddish facial skin, nape plume; Chinese Egret – bill yellow, feet greenish-yellow; and Pacific Reef Egret (White morph) – bill greenish-yellow

[above left shows the yellow-green facial skin; above right shows adult breeding back plumes]

Problems with this ID:
“The Intermediate Egret is noted in local literature to have a yellow bill even in breeding (See DR Wells 1999 and Craig Robson 2002). And as I mentioned, there are no prior records of Intermediate Egrets nesting in the Peninsular.

“However a number of web sites and images posted (e.g. on OBI) mention or show black beaks. In addition these birds have chest filoplumes in addition to the back plumes. The chest plumes are even present for the bird in flight (top, with nesting material) in high quality images but are windswept against the body. The yellow-green facial skin in breeding also supports the ID.

“I am grateful for comments from two of our prominent ornithologists:

“David R Wells (The birds of the Thai-Malay Peninsula, Volume 1 & 2) says: ‘This is quite exciting. You have Intermediate Egret in breeding colours here. Plumes seen occasionally in the Peninsular, but I have never heard of actual bare-part courtship colours (including black bill). Also, no record of nesting behaviour before. To my knowledge, no record of this egret breeding north of Java or south of Indochina (not in Thailand). Well spotted – again, and situation needs monitoring.”

Slim Sreedharan says: ‘Your hunch is right. It is quite likely to be the Intermediate Egret – they do not ALWAYS have a yellow bill during the early stages. But the plumes visible will give you the clue. Hard to separate from the Large except when seen side by side but the Large does not have the filoplumes on the breast. The Chinese Egret does not breed here.’

“Note that the 5 images posted are from 5 different birds. The population of Intermediate Egrets breeding here is in excess of 50.

“I have elected to keep this site location ‘unclear’ for the moment as concerned about disturbance to nesting.”

Dato’ Dr Amar-Singh HSS
South Perak, Malaysia (Padi fields, extensive wetlands)
30th March 2012
Equipment: Nikon D7000 SLR with Sigma AF OS Zoom 150-500mm, handheld