^8 Alexander, Changes in Colour of Bill of Moor-Hen. [j.fT,] , 



The Changes in Colour of the Bill of the Black 



Moor^Hen (Gallinula tenebrosa). 



By W. B. Alexander, M.A., Keeper of Biology in the 

 Western Australian Museum. 



In Novitates Zoologicce, vol. xxv., No. i, p. i (1918), Miss Frances 

 Pitt gives an account of the colour changes of the beak and shield 

 of the young English Moor-Hen {Gallinula chloropus), accom- 

 panied by a plate of coloured drawings of the heads of live speci- 

 mens at different ages. The most interesting feature of the 

 changes detailed is that when first hatched the young English 

 Moor-Hen has a bright red shield on the forehead, the upper part 

 of the beak being the same colour. This red patch dwindles in 

 size until it is entirely lost when the bird is seven weeks old. 

 The complete disappearance of all colour coincides with the 

 growth of the feathers, so that while the bird is in its immature 

 plumage its bill is dull greenish-grey in colour. Some months 

 later, during the autumn or winter succeeding its birth, the young 

 Moor-Hen acquires the adult plumage and the frontal shield and 

 bill re-acquire their bright red colour. Subsequently this colour 

 does not vary in brilliancy even during the moult. 



I believe that the Austrahan Black Moor-Hen [Gallinula 

 tenebrosa) undergoes similar if not identical changes. Curiously ' 

 enough, the matter had been brought to my notice by Mr. J. 

 Higham only a few days before the arrival of the part of the 

 Novitates containing Miss Pitt's article, and I am indebted to 

 him and to Mr. T. Carter for allowing me to examine two speci- 

 mens of young Black Moor-Hens obtained by them at the Warren 

 River, Western Australia, on 28th March, 1919. 



It is no doubt well known to most Australian ornithologists 

 that the young Black Moor-Hen as a chick has a bright red frontal 

 shield. This presumably remains, as in the English Moor-Hen, 

 until the down is replaced by feathers. The young bird in 

 immature plumage is, as described by Mathews (" Birds of Aus- 

 tralia," vol. i., p. 232)7 similar in general colour to the adult, 

 though perhaps rather browner on the back ; the under surface 

 is paler, and the feathers on the chin and lower abdomen have 

 white tips. A hne round the bend of the wing and the outer 

 edge of the first primary are white. Mathews and, as far as I can 

 discover, all previous authorities have failed to record the fact 

 that, just as is the case in the English Moor-Hen, the bird while 

 in this immature plumage has no red on the beak. Mr. Carter's 

 notes on the labels of the two specimens referred to above, from 

 the Warren River, read : — 

 $. — Bill mottled green and black (lower base green), frontal 



plate black. 

 S- — BiU mottled green and horn. 



Field notes as to the length of time during which this immature 

 plumage lasts would be of interest. 



