71 8 NESTS AND EGGS OF AUSTRALIAN BIRDS. 



sound extraordinary, or different from anything with which they were 

 previously acqviainted. 



" I re-visited Knockei-'s Bay on thc^ 10th of Febiiiary, and having with 

 some difficulty penetrated into a dense tliicket of cane-like creeping 

 plants, I suddenly foimd myself beside a mound of gigantic proportions. 

 It was fifteen feet in height and sixty feet in circumference at the base, 

 the upper part being about ai third less, and was entirely composed of 

 the richest description of light vegetable mould. On the top were very 

 recent m.-rks of bird's feet. Tlie native and myself immediately sot to 

 work, and after an hour's extreme labour, rendered the more fatiguing 

 from the excessive heat and the tormenting attacks of mjrriads of mos- 

 quitoes and sand-flies, I succeeded in obtaining an egg from the depth 

 of about five feet. It wa,s in a perpendicular position, with the earth 

 siUTOiuiding and very lightly toiiching it on aU sides, and without any 

 other material to impart warmth, which, in fact, did not appear necessary, 

 the nionnd being quite wai-m to the hands. The holes in this moimd 

 commenced at the outer edge of the sitmmit and ran down obliqviely 

 towards the centre : their direction, therefore, is not unifoiTn. Like 

 the majority of the mounds I have seen, this was so enveloped in thickly- 

 foliaged trees as to preclude the possibilitv of the sun's rays reaching any 

 parti of it. 



" Tlie mounds differ very miich in their composition, form, and situa- 

 tion. Most of those that art^ placed near the, water's edge were foiTned 

 of sand and shells, without a vestige of any other material ; but in some 

 of them I met with a portion of soil and decaving wood. When con- 

 structed of this loose material they are very irregular in outline, and 

 often resemble a bank thrown up by a constant heavy surf. One 

 remarkable specimen of this description, situated on the southern side 

 of Knocker's Bay, ha.s the appearance of a bank, from twenty-five to 

 thirty feet in length, with an average height of five feet. Another 

 even more singular is situated at the head of the harbour, and is com- 

 posed entirely of pebbly ironstone, resembling a confused heap of sifted 

 gravel. Into this I dug to the depth of two or three feet without finding 

 anv change of character. It mav have been conical originally, but is 

 now without any regularitv, and is verv extensive, covering a .space of at 

 least one hundred and fifty feet in circumference. These remarkable 

 specimens would, however, seem to be, exceptions, as bv far the greater 

 number are entirely formed of light, black vegetable soil, are of a conical 

 form, and are situated in the densest thickets. Occa.sionally the mounds 

 are met with in barren, rocky and sandy situations, where not a particle 

 of soil similar to that of which they are composed occurs for miles around. 

 How the soil is produced in such situations seems unaccountable. It 

 has been said that the parent birds bring it from a great distance ; but 

 as we have seen that they readily adapt themselves to the difference of 

 situation, this is .scarcely probable. I conceive that they collect the 

 dead leaves and other vegetable matter that may be at hand, and which, 

 decomposing, forms this part.icular kind of soil. The mounds are doubt- 

 less the work of many years, and of many birds in succession. Some of 

 them are evidentlv verv ancient, trees being often seen growing from tlieir 

 side. In one instance I found a tree growing from the middle of a 



