The Zoologist— April, 1874. 3929 



if they were one body, and showing the gorgeous blue, yellow and red of 

 the upper side gleaming in the sunshine : screaming meanwhile as they flew 

 with harsh discordant cries. This gaudy-coloured and noisy bird seems to 

 proclaim aloud that it fears no foe. Its formidable beak protects it from 

 every danger, for no hawk or predatory mammal dares attack a bird so 

 strongly armed. Here the necessity for concealment does not exist, and 

 sexual selection has had no check in developing the brightest and most con- 

 spicuous colours. If such a bird was not able to defend itself from all foes, 

 its loud cries would attract them ; its bright colours direct them to its own 

 destruction. The white cockatoo of Australia is a similar instance. It is 

 equally conspicuous amongst the dark-green foliage by its pure white colour, 

 and equally its loud screams proclaim from afar its resting-place, whilst its 

 powerful beak protects it from all enemies excepting man. In the smaller 

 species of parrots the beak is not sufficiently strong to pi'otect them from 

 their enemies, and most of them are coloured green, which makes them very 

 difficult to distinguish amongst the leaves. I have been looking for several 

 minutes at a tree, in which were scores of small green parrots, making au 

 incessant noise, without being able to distinguish one ; and I recollect once 

 in Australia firing at what I thought was a solitary 'green-leek' parrot 

 amongst a bunch of leaves, and to my astonishment five ' green-leeks ' fell to 

 the ground, the whole bunch of apparent leaves being composed of them. 

 The bills of even the smallest parrots must, however, be very useful to them 

 to guard the entrances to their nests in the holes of trees, in which they 

 breed."— P. 196. 



It is really delightful to accompany a man who rides a favourite 

 hobby so well, and with such entire confidence ; but it may possibly 

 strike the reader that all big beaks, — for instance, those of the horn- 

 bill and toucan, — are not equally adapted with tliat of the macaw 

 for battle with the hawk and the eagle. Mr. Belt sees this, and 

 explains that the toucan, by means of its powerful beak, can 

 " defend itself against all its enemies, especially when nesting in 

 the hole of a tree." This assimilation of the objects of two such 

 dissimilar beaks as those of the macaw and the toucan is certainly 

 ingenious and plausible ; but since both parrots and toucans nest 

 in trunks of trees, both possess gaudy and most conspicuous 

 plumage, I think it requires an additional hypothesis to explain 

 why the beaks in these two tribes should be so remarkably differetit 

 in all their characters. There is, however, a feature in these specu- 

 lations which perhaps has been too much overlooked; they induce 

 investigation, and this is always beneficial, even though instituted 

 for the unworthy purpose of disputing a conclusion. Investigation 



