30 SCIENTIFIC SURVEY OF YORK AND DISTRICT 



We possess most types of fresh water, with the exception of large lakes 

 and mountain tarns. The following are quite close to the city. Hob 

 Moor (2 m.) contains old brick workings, giving both deep and shallow 

 clay-bottomed ponds. The Ings begin beyond the city, and extend along 

 the banks of the Ouse. They are water meadows of alluvial deposit with 

 ditches and hollows periodically flooded. Bootham Stray (2 m.) is a flat 

 stretch with ponds and ditches, typical of the grass-lands of the district. 

 Stockton Common, already mentioned, contains private fish-ponds, old 

 ' stews,' and marl-pits typical of the arable lands. The Foss is a silted-up, 

 overgrown, disused water-way, extremely rich in its varieties of aquatic 

 life. The above description is intended to give a rapid survey of the 

 regions which the York naturalists have found most productive, in order 

 that members of the British Association may readily select places to visit 

 with the greatest advantage. 



The various forms of life to be found in these regions are now to be 

 discussed. In the account of them which will be given such species as 

 would be almost certain to be present will not be mentioned. 



Birds and Mammals. 



The Derwent Valley is a nesting place for large numbers of snipe, 

 redshank, and green plover, but during the past three years the heavy 

 floods during the season of incubation have destroyed large numbers of 

 nests. During the winter these flooded areas are the resort of many 

 thousands of mallard and widgeon. There are also large numbers of teal, 

 pochard, tufted and golden-eyed duck. 



Skip with Common has also been adversely affected by floods. A colony 

 of about 500 pairs of black-headed gulls has been established here for 

 many years. About ten pairs of shoveller have nested here, as also do the 

 pochard, mallard and teal. There are also always several pairs of nightjars 

 during the summer months. The green plover is becoming scarce in this 

 area, because its nests are raided by the black-headed gulls, and when 

 situated on arable land, much of which has been reclaimed from the 

 common, many eggs are destroyed by farmers' rollers. 



The thickets of birch and sallow in Askham Bog are the summer 

 haunts of sedge warbler, reed bunting and the garden and blackcap 

 warblers. The rarer reed warbler has nested here in recent years, and so 

 has the grasshopper warbler. The sparrow-hawk, kestrel and jay occur, 

 and also the coot, little grebe and snipe. Askham Bog was once the 

 haunt of the bittern. 



At Strensall Common was once a colony of black-headed gulls, but they 

 were driven away by the soldiers from the camp, who constantly raided 

 their nests. Numbers of duck, which nested on the marshy parts, also 

 suffered from the same cause. A few pairs of mallard and tufted duck 

 still occur. Curlews may often be seen and heard, and in recent years 

 several pairs have nested on the common. The long-eared owl and tawny 

 owl nest in the fir thickets, and so also does the great spotted woodpecker. 

 The jay and carrion crow, the sparrow-hawk and the kestrel also occur in 

 good numbers. Ringdoves nest here in large numbers, and the rarer 

 stockdove occurs. 



