435. Pycnonotus blanfordi robinsoni

(435) Pycnonotus blanfordi robinsoni Ogilvie-Grant.
THE SIAM OLIVE BULBUL.
Pycnonotus plumosus robinsoni, Fauna B. I., Birds, 2nd ed. vol. i, p, 420.
Pycnonotus blanfordi robinsoni, ibid. vol. viii, p. 616.
The Siam Olive Bulbul appeared to me to be the Eastern repre¬sentative of the preceding species but Kloss, with far more material, thinks otherwise. It is said to occur from Patani in the extreme South of peninsular Siam, up the East coast, perhaps entering the borders of East Tenasserim near Tavoy, as far North as Ayutbia, Natrang and Kraben, whilst there are also specimens, apparently identical, from Annam in the British Museum.
There is little that can be added to the excellent account of this bird given by Herbert (Journ. Siam Nat. Hist. Soc. vol. vi, p. 94, 1923) under the name of P. blanfordi, robinsoni not then being admitted:—
“One of the commonest birds in Bangkok, and it may be found nesting in nearly every compound, yet it is one of the instances where I delayed collecting a series of eggs to show the difference in marking until it was too late.
“The nest is usually built within easy reach of the ground, sometimes in the steep fork of a croton, though more often on the light branches of some small tree, or even a creeper. It is con-structed of fine grasses or, where there are cocoanut-palms near by, of fibre, and cemented together on the outside with small patches of cobwebs. The inside is hemispherical in shape and is neatly finished with the same materials, but the entire structure is always very thin.
“The nesting season commences in January and extends to the latter part of September, though the hot weather and early part of the rains are the more general times. These birds do not make successful parents for, despite their devotion and fussiness, they are in many ways very casual ; this is borne out by the number of instances in which the old birds may be seen in attendance on a single young one. Two eggs are laid and very occasionally three, but some-times only one is hatched, and even when there are two young ones some disturbance usually causes the loss of one of them. The nest is often very insecure, and several times I have known them to be capsized in a wind-storm ; on one occasion I placed the nest in a more secure position in a Croton and, after I had replaced the half-fledged youngster, the agitated parents continued their family duties. Two or more broods are raised during the season.
“The eggs are moderately broad ovals in shape, and only slightly compressed towards the smaller end ; they are fine in texture but without much gloss. The ground-colour is pale pink or pinky white, with markings in deep red or reddish brown, and secondary markings of pale purple. They show much variety and are handsome eggs, though not so richly marked as those of many other Bulbuls. The markings consist of speckly and blotchy spots of irregular form of varying depths of colour, and are more closely massed in a zone or cap at the large end. The average size of the egg is 21.5 x 15.5 mm.”
I have a very fine series of the eggs of this Bulbul, given to me by Sir F. W. Williamson and Mr. Herbert and, as a series, I should call them poorly-marked eggs, quite indistinguishable from those of Otocompsa jocosa. Most eggs are only marked with speckles and spots, blotches are quite uncommon, and any depth of pink in the ground-colour is rare. On the whole they are more slender in shape than Otocompsa eggs.
One hundred eggs average 21.6 x 15.6 mm. : maxima 23.0 x 16.2 and 22.2 x 16.7 mm. ; minima 20.1 x 15.1 mm.
Williamson’s eggs were all taken between the 1st February and the 18th June, but odd eggs may be taken, I understand, in almost every month of the year.
The normal clutch of eggs is two, and out of seventy-six nests examined by Williamson only four contained clutches of three eggs.

BookTitle: 
The Nidification Of Birds Of The Indian Empire
Reference: 
Baker, Edward Charles Stuart. The nidification of birds of the Indian Empire. Vol. 1. 1932.
Title in Book: 
435. Pycnonotus blanfordi robinsoni
Book Author: 
Edward Charles Stuart Baker
CatNo: 
435
Year: 
1932
Page No: 
402
Common name: 
Siam Olive Bulbul
M_ID: 
22040
M_SN: 
Pycnonotus blanfordi conradi
Volume: 
Vol. 1
id: 
13620

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