Page:The Zoologist, 4th series, vol 1 (1897).djvu/437

Rh Purple Heron, quote the account by Lieut.-Col. Irby of his visit to a colony in the south of Spain. It is interesting to learn that the latter ornithologist only found three or four eggs in each nest, in the place of five or six in rny own experience. Abundance of food may perhaps account for the greater fecundity of the Herons I came into contact with, for Dresser states that the Purple Heron is said to devour large numbers of young Green Frogs (Rana esculenta). Now these creatures abound in the large ponds before mentioned, and the Herons must have no difficulty in eating their fill throughout the nesting season. Some divergence of opinion may be noted on the dimensions of the eggs of the present species. Seebohm states that they are indistinguishable from those of A. cinerea, except that they are slightly smaller. He gives the following measurements: length 2·45 to 1·95 in. by 1·75 to 1·45 in. in breadth. Dresser states that eggs taken in Hungary varied from 2$4⁄10$ × 1$23⁄40$ to 2$10⁄40$ × 1$27⁄40$ in. The average dimensions of eggs of A. cinerea the latter author gives as 2$1⁄2$ × 1$27⁄40$ in. Saunders, in his 'Manual of British Birds,' states that average eggs of A. purpurea measure 2·2 × 1·5 in. These dimensions I find approximate to the sizes of the eggs I took in France; my largest specimen being equal to 2·23 in. in length by 1·62 in. in breadth, and my smallest but 1·95 × 1·47 in. An attenuated egg, however, has a length of 2·30, but a breadth of only 1·50 in.

Comparing these measurements with those of eggs of A. cinerea kindly supplied me by Mr. R.J. Ussher, who has had considerable experience with the latter species in Ireland, I think it may be laid down as a general rule that large eggs of A. purpurea in size rarely overlap those of small ones of A. cinerea. According to the above-named ornithologist, eggs of A. cinerea vary between 2·63 × 1·71 in. and 2·39 × 1·7 in. These dimensions, I may say, tally with those of eggs in my own collection.