12 Coward, Faunal Survey of Rest heme Mere. 



the partly-exposed roots of the alders, or in the thick 

 clumps of rushes or other plants which grow actually in 

 or close to the water. Not infrequently the water grad- 

 ually washes away the soil from around the roots of the 

 trees which grow at the edge of the mere, and in conse- 

 quence they fall during strong winds ; the Wren almost 

 invariably builds amongst the exposed roots of these 

 fallen timbers. 



Naturally all three of 

 Lhelidon rustica (Linnaeus.) our regular summer 

 Hirundo urbica Linnaeus. swallows are constantly 

 Riparia riparia (Linnaeus). to be seen over the 



waters during their stay, 

 but the numbers vary considerably. When the birds first 

 arrive in spring they remain about the water for a period, 

 the length of which mainly depends upon the date of 

 arrival and the weather at the time. Should a cold snap 

 follow the arrival, the birds find far more food above the 

 water than in the surrounding districts, and they do not 

 distribute to their nesting haunts until a return of more 

 favourable conditions. At night they roost gregariously 

 in the reed-beds. But even after the home-breeding birds 

 have settled down there are repeated arrivals of passage 

 birds, spending a few days in feeding as they move slowly 

 northward, keeping more or less regular pace with the 

 advance of spring. The Swallow nests in the boat-house 

 and a summer-house close to the water's edge, but the 

 House Martin goes further afield. There is no suitable 

 sandy bank of sufficient depth for the Sand Martin. As 

 the summer advances the numbers of all three species 

 which feed above the water increases ; local birds begin 

 to pack, families joining families and forming small flocks, 

 and these repair to the reed-beds for roosts ; then the 

 passage birds from the north arrive, and in the late 



