250 THE NESTS AND EGGS OF BRITISH BIRDS. 



2'5 inches in length, by Vj inch in breadth. Incubation, 

 performed by both sexes, lasts twenty-five or twenty-six 

 days. 



Diagnostic characters : The size, colour, and 

 texture of the eggs of the Heron readily distinguish 

 them from those of any other species breeding in our 

 islands. 



Before drainage and modern land improvement 

 destroyed its strongholds, the Bittern {Botaiirus stellaris) 

 bred regularly in the fens and marshes of East Anglia, 

 in various parts of Scotland, and in Ireland. There can 

 be little doubt that this species does not breed anywhere 

 in our islands at the present time. The fact could 

 scarcely be overlooked, as the birds would be sure to 

 attract attention by their singular booming cry. The 

 eggs are laid in April and May, sometimes as early as 

 March. The nest is built upon the swampy ground, 

 amongst dense aquatic vegetation, and is composed of 

 dead and rotting reeds, flags, and other herbage — a mere 

 heap of rubbish, with a shallow cavity at the top. The 

 eggs are from three to five in number, four being an 

 average clutch. They are uniform brownish-olive or 

 buff in colour, very similar in tint to those of the Phea- 

 sant. It may also be remarked that the interior of the 

 shell when held up to the light is brown, not green as is 

 universally the case with the true Herons. Average 

 measurement, Ti inches in length, by r5 inch in breadth. 

 Incubation, performed chiefly by the female, lasts from 

 twenty-three to twenty-five days. Only one brood is 

 reared in the year. 



