126 (^.ILP.ERT, The Oraiu/e-z.'iin/cd TrccRnuncr. U^i^^"" 



material in position, the other stood close by pouring out its sweet 

 notes, "tzir, zit-zit, tzir-zit-zit, tzir,-zit-zat-zat." F^or the time 

 being, further observations were informally interrupted. Several 

 keen-witted bush boys ap])eared on the scene, who know this 

 bird by the name of "Bark-tit" or "Bark-pecker." They were 

 not long in finding out the cause of the observer's interest. A 

 compact was entered into, that they should leave the nest intact, 

 and neither disturb nor interfere with the birds or eggs. They 

 did not touch the nest, but the smoothness of the trunk bore 

 evidence as to the frequency with which it was reached. The 

 birds deserted the nest when almost completed, owing, no doubt, 

 to continual hindrance by the youthful observers. Later, this 

 pair was found high up in a Stringy-bark tree building a nest. 

 This time they were o])erating well out of the way of boy 

 marauders, and eventually they brought forth a family of two. 

 This bird will build in the same tree, spring after spring, until 

 molested, when it abandons tliat tree, and selects one oi a dilter- 

 ent species. 



At East Hills, X.S.W., on the 9/9/1917, Mr. H. Kean, 

 R.A.O.U., and the writer saw seven of these birds engaged in 

 building a nest in a swamp-oak tree. Two of the seven had a nest 

 seventy-five yards away, which, later on, was occupied by three 

 young. While ])hotographing these birds, four have been ob- 

 served bringing in food for the young. As each bird fed a 

 young one, it Hew to a tree in the vicinity, where all four gath- 

 ered, and then flew off to collect food for the young in a second 

 nest one hundred yards away. Often two birds have been de- 

 tected feeding one sitting on a nest. This procedure is mis- 

 leading, for, on climbing to inspect the nest, one exj)ects to see 

 young, but in their place there are fresh eggs. 



If we follow uj) the various stages of development in the 

 Orange-winged Tree-runner's life, we shall see that each stage 

 suits its immediate environment — first, the adult bird upon the 

 branch or trunk of the tree, on which it toils for the means of 

 its existence; then the nest, which resembles the butt of a broken 

 dead branch ; the eggs, that harmonise with the velvety lichen 

 whereon they lie ; the young birds when fledged that agree with 

 the nest wherein they crouch. All this wonderful unconscious 

 mimicry suggests that the Orange-winged Tree-runner was 

 evolved' in an age when birds of j^rey and tree-climbing pre- 

 daceans were abundant, in consecpience of which, every variation 

 that occurred in the direction of protective coloration, or adap- 

 tation, conducive to greater security, was preserved. 



Lastly, the i)eculiar methods this bird adopts when searching 

 for insects may be referred to. .\s it ho|)s down the branch, it 

 throws itself from one side to the other, so that its downward 

 inspection of the chinks in the bark, on both sides of the branch, 

 is achieved in one descent. As soon as one branch has been ex- 

 amined, it either continues its search in the larger crevices of 

 the trunk, or flies to the to]) of another branch, in its endeavours 

 to make its arboreal host yield up its stores of lurking insects. 



