 In 1877 three stones were found in a cavern on Rodrigues , each near a Rodrigues solitaire skeleton , and were inferred to be the gizzard stones mentioned by Leguat . One of the stones was examined and found to be dolerite : somewhat rough , hard and heavy , c . 50 g ( 1 3 ⁄ 4 oz ) , but hardly flat on one side as described by Leguat . This could be due to its association with a young individual . Although Leguat asserted that the bird hatched with the gizzard stone already inside , in reality adults most likely fed the stones to their hatchlings . 
