4 Coward, Faunal Survey of Rostherne Mere. 



mussels, Anodojita cygnea, but we have not found the 

 shells of this mollusc with tooth-marks of the Otter at 

 Rostherne. Possibly the greater depth of the water 

 makes the capture of the fish more difficult than in the 

 shallower meres, but this would not apply to the mussels 

 which are easily seen in the shallower portions. 



The Water Vole is de- 

 Arvicola ajnphibius (Linnaeus), cidedly more abundant 



along the banks of 

 the outflow, Blackburn's Brook, than on the edge of the 

 mere. It feeds on the edge of the brook and in the osier- 

 bed at the south end of the mere. We have never found 

 its spherical nest, supported on a raft of cut reed-stems, in 

 the reed-beds at Rostherne, though we have occasionally 

 found it on other Cheshire meres ; at Rostherne the nests 

 appear to be underground. 



The Brown Rat is at 

 Epimys norvegicus (Erxleben). once the most abundant 



and troublesome of the 

 aquatic mammals. It is a common and destructive pest in 

 all game-coverts, and those which surround Rostherne 

 Mere are not exceptions. It burrows in the banks, no 

 doubt aiding their erosion ; it lives in the entangled roots 

 of the waterside alders, and raids the nests of birds which 

 breed in the reeds. Its omnivorus tastes lead it to 

 destroy vegetation as well as to kill and devour other 

 animals. The eggs of Mallards, Coots and other birds 

 are sucked by the Rat, and on one occasion we heard a 

 scuffle in the reed-bed and saw a full-grown Rat emerge, 

 followed by an irate Coot ; the young Coots had hatched 

 a day or two before and were scattered amongst the reeds 

 near the nest, and on this occasion the parent bird had 

 probably driven the intruder away. Close to the hole, into 

 which the Rat went so soon as it saw that it was observed. 



