Zoology 6i 



the long-cared bat {Plccotii^ atiritus), and the barbastclle [Barhastella 

 harhastelltts) also occur, but the last-named appears to be comparatively 

 rare. The fox is general except in the Fcnland, where it is a straggler. The 

 badger has been noted occasionally in different parts of the County, and 

 the otter occurs in the river near to, and above, Cambridge, but is rather 

 infrequent. The stoat and weasel are plentiful, but the pine marten and 

 true polecat are extinct. Some of the later records of the last-named 

 species probably refer to polecat-ferrets and not to genuine wild specimens. 

 The- common shrew, the pigmy shrew, and the water shrew aU occur, the 

 first-named being the commonest. The dormouse appears to be very rare, 

 and, of the voles, the water vole and the short-tailed vole are prevalent, 

 while the bank vole is uncommon. The long-tailed fieldmouse appears 

 to be local, and the harvest mouse has not often been recorded. The red 

 squirrel occurs in various localities, while the American grey squirrel has 

 only been occasionally reported. 



AVES' 



In general, a county is a most unsatisfactory unit for ecological and natural 

 history studies. This is even more obvious when dealing with birds than 

 it is with more sedentary animals. Indeed, the only reason for choosing 

 counties as a basis for studies of bird distribution is that they provide 

 accurately demarcated areas of convenient size. Accordingly, the object 

 of this brief sketch is to call attention to the main bird habitats of the 

 Cambridge district without deference to county boundaries.^ 



To the west of Cambridge lies a countryside of heavy clay soils (see 

 Fig. 29), mostly under cultivation, with some small mixed deciduous 

 woods and copses in which oak predominates. Here the birds are typical, 

 in general, of the Midlands, although the absence of larger woods with 

 old trees restricts the fauna considerably. Indeed, as D. Lack has pointed 

 out, Cambridge itself is almost the only part of the district where old 

 deciduous trees are numerous, and where tree-climbing and hole-nesting 

 species are common. 3 Five species of tits, three woodpeckers, and the 

 stockdove, are all associated with old trees and may be observed on the 

 Backs. Here, too, the nuthatch is common, and the presence of the 

 somewhat elusive tree creeper is shovrai^ by the numerous roosting holes 

 scratched out of the bark of almost every specimen of Sequoia gigantia. 



' By W. H. Thorpe, M.A., Ph.D. 



^ A more detailed account is the excellent study by D. Lack, The Binh ofCamhrid<^e- 

 shire (1934). I am indebted to this, and to the reports of the Cambridge Bird Club. 

 3 D. Lack, op. cit. p. 13. 

 t W. H. Thorpe, "The Roosting Habits of the Tree Creeper", British Birds, xviii, 



20 (1924)- 



