Page:The Emu volume 3.djvu/33

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Vol. III. 1903 ]
Milligan, Notes on a Trip to the Stirling Range.
15

27 miles, and produced three male birds as the result of his labours. From what has been stated cabinet naturalists will perceive that their brothers in the field make many sacrifices in the interest and pursuit of a common study.

Although there is not, perhaps, any doubt that the birds we secured were M. pulcherrimus, nevertheless there are some minor differences between them and Gould's bird which it may be desirable to mention. In the first place, the total length of Gould's bird is given as 5¼ in. and the tail as 3¼ in. In the Stirling Range bird the total length is ⅞ of an inch greater, but the tail measurements are equal, thus confining the difference to the body length, which is material. Gould's measurements, however, are not always reliable, and as an example of such let me mention a similar inaccuracy in Gould's recorded measurements of M . elegans. Again, Gould gives the measurements of the bill of his bird as 1/16 of an inch. Obviously this is an error, and should read 7/16. I think, therefore, these points of difference may be put aside.

Now, on the question of colour, Gould gives the colours of the crown of the head and eye-spaces of his bird as glossy violet-blue and verditer blue respectively. In the Stirling Range bird the colours are deep violet-blue with a purple glint and light cobalt respectively. Possibly, and probably, on comparison, the shades of blue in each bird would prove identical, and the differences may only rest in the discrimination of the respective writers. Some other minor differences appear in the tail colours and in the purity of the white on the abdomen, but these may be regarded as trivial. Attention, however, must be directed to the facts that in each of the Stirling Range birds dingy brown feathers appear in the cap, and that the upper tail coverts are of the same shade. Upon these facts the following questions arise:— (a) Must these dingy brown feathers be taken to be permanent? (b.) If not, are they the badges of approaching adolescence? and (c.) If not, are they the remnants of a plumage being cast off?

The persistency of the brown feathers almost negatives the notion of their being the badge of approaching adolescence, for according to the law of averages it is scarcely possible that five male birds could be shot promiscuously and all prove young males.

As against the first notion the additional fact must be recorded that the season was an abnormally late one, and that in one specimen the uppermost tail feathers showed they were last year's by their faded and abraded appearance, and that in another specimen the uppermost and undermost pairs of tail feathers were only ¾ of an inch long—all which point to a moult in progress. As a counter fact, however, it may be stated that we shot male birds of M. elegans and M. splendens all of which were in complete new plumage.

If the first and second questions are to be answered in the negative, then the theory that the adult male annually assumes a nuptial plumage is well founded. To say with definiteness