Ocsooe 



1956 



r J 



Bakkk. The Su-alloiK-iiu/ of Sfoncs by .Animals 



89 



Xot all stones collected by Moas were pure white, as reports are given of 

 'dark stones' and "transparent flinty stones' having been found in the heaps. 

 Xor were the stones always found to be well rounded. 



Roger Duff (1949), referring to the food of the Moa states, "The number. 

 size, and weight of the gizzard stones required by Dinornis }uaxi)in<s tu 

 digest his food were more fully realized than ever before when the complete 

 >keleton could be found regularly. The average size approximated a half- 

 crown piece, but pebbles up to tour inches were noted. Normally, the stones 

 and food remains filled a seven pound biscuit tin, and an average collection 

 of 220 stones weighed five and a half pounds. The pebbles were of dark grey 

 uaterworn greywacke such as occur plentifully in the stream beds of the 

 Waipara and its tributaries to the south and the Hurunui and its tributaries 

 to the north. The handsome white pebbles found elsewhere were rare. An 

 interesting realization was that the majority of the stones showed little 



Fig. 5 — Highly polished gizzard stones, of quartz, chalcedony and jasper. 

 (Photo, by G. A. Thomas, from the collections of th^ National Museum, Melbourne). 



evidence of wear. This demonstrated that the small heaps of highly worn 

 'Moa-stones' so widely found by farmers breaking into virgin soil, do not 

 represent the final remains of a Moa whose hones had disappeared, but 

 have been passed or vomited when they become too worn for their purpose." 

 Another struthious bird, (rcnyornis newtoni, whose remains are found 

 near Lake Callabonna in South Australia, evidently swallowed small stones, 

 as E. C. Stirling ( 1900 ) states, "The positions of the bird remains were 

 indicated by the presence of circular surface patches of gizzard stones, 

 consisting of coarse sand and small siliceous pebbles not exceeding three- 



