The Food of Rattus norvegicus Berk. in an Area of Sea Wall, Saltmarsh and Mudflat

Abstract

(With 1 Figure in the Text) It has long been known that rats, living independently of man, occur along the coast of Britain, but relatively little information is available about their food. Most of the records can be summed up in the words of Barrett-Hamilton & Hinton (1910-21, p. 622); 'on the seashore the food is what is cast up by the sea, together with prawns, shrimps, shellfish, eggs and young of sea birds, and vegetable matter'. Further observations are, however,- available from the Islands of Norderoog (Steiniger 1948) and Scharhoern (Habs & Heinz 1951), off the west coast of Germany. On both islands, not only did the rats eat the eggs of many birds, but they also (particularly on Norderoog) caught and ate live adult birds. The seeds of Elymus arenarius L. (Norderoog and Scharhoern) and Chenopodium spp. (Norderoog) were eaten during the late summer and autumn. Steiniger also mentions that in late December apparently almost all the plants on Norderoog were being eaten, but particularly striking were traces of gnawing at the rhizomes of Triglochin maritima L. On these German islands, both of which are bird sanctuaries, observations on the rats were incidental to rat control to protect the birds. In the present study it was possible to make records of food for a whole year in a rather different type of coastal habitat on Bridgemarsh Island in Essex, where breeding birds were few and where occurred only three of the twenty-nine angiosperms noted from Scharhoern.