Vol. XVII. 



ig^s'"'] White, Notes upon Eggs of the Wedge-tailed Eagle. I^g 



Notes upon Eggs of the Wedge^tailed Eagle (Uroaetus 



audax). 



By. H L. White, R.A.O.U., Belltrees, N.S.W. 



The six sets of [Uroaetus audax eggs which I send for exhibition 

 at this monthly meeting of the R.A.O.U. are not typical — in fact, 

 they are abnormal in coloration. 



It is extremely hard to decide upon the typical colour of 

 Uroaetus eggs. . During the last two seasons I have examined 

 upwards of 50 sets, every one of which differed from what I had 

 decided as a typical pair in my collection. The more one sees of 

 eggs of this species the more the fact is made clear that to establish 

 a type is almost impossible. 



My collection contains 30 clutches ; that of my friend Mr. J. H. 

 Bettington, of " Terragong," Merriwa, has a still greater number. 

 This gentleman has the largest collection of Wedge-tailed Eagle's 

 eggs in Australia. 



Some thirty years ago the Eagles existed here in hundreds, but 

 are now rare ; on the other hand, at " Terragong," 45 miles due 

 west, the birds are still very numerous, and Mr. Bettington might 

 easily collect 30 clutches of eggs during the spring. 



In my collection are specimens from each State of the Common- 

 wealth, all showing considerable variation, but none exhibiting 

 the extreme difference found in those collected by Mr. Bettington 

 on a comparatively small area round his estate. Not only do the 

 " Terragong " eggs show great variation in size and shape, but 

 the coloration is most unusual. Some specimens are almost 

 spherical, while others are rather long ovals. The shades of 

 colour range from pure white and bluish-white to dark rusty-red, 

 through many shades of lilac, brownish-red, and purple. 



The Merriwa country is chiefly undulating, black soil, volcanic 

 formation, very rich, and well watered. I am puzzled as to 

 whether some particular chemical in food or soil has anything to 

 do with the bright coloration' of the eggs generally. Some clutches 

 of Ravens' [Corone australis) eggs obtained in the locality show 

 a bright deep greenish-blue colour, quite unlike anything I have 

 seen elsewhere. As the Merriwa country has been ringbarked 

 for many years. Eagles find a difficulty in securing proper material 

 for nest construction. During late years some have utilized the 

 dead stalks (frequently with roots attached) of the variegated 

 thistle {Carduus lanceolatus), which grows most profusely in the 

 locality. These thistle-stalks become very limp in damp weather, 

 and the nests do not last long. In one particular instance the 

 stalks were so unstable that they kept slipping from their position, 

 and eventually formed a heap, equal to a dray-load, on the ground 

 underneatli. The birds exhibited remarkable patience, and at 

 last, with the aid of Angophora twigs, completed the nest. 



Of the eggs sent, the pure white clutch marked " A " is a gift 

 from Mr. Bettington to the R.A.O.U. collection. Had this set 

 been taken near the coast a suspicion might have arisen as to its 



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