By River and Pool. 207 



continues into October, and during some years is 

 even prolonged into November, Sanderlings, Cur- 

 lew Sandpipers, and Knots, birds that migrate 

 amongst the latest in spring and breed in the high 

 north, are some of the first to reappear in autumn, 

 even at the end of July or early in August. Com- 

 mon Sandpipers, as their name suggests, are abun- 

 dant during their short stay at the mouths of these 

 northern rivers previous to passing south. In the 

 H umber district especially, vast flights of Dunlins 

 often appear upon the mud- flats towards the end of 

 August, and remain for the winter. When the rising 

 tide drives them from the muds, they often resort to 

 the fields to wait until the ebb. The movements 

 of these birds are most interesting, as a vast flock 

 wheels and spreads out or closes up with as much 

 precision as drilled troops. Scattered amongst them 

 are many odd Stints and Sanderlings and Ringed 

 Plovers. Curlews, Whimbrels, and Bar-tailed God- 

 wits also appear about these estuaries during migra^ 

 tion time, and some of them remain upon them 

 throuufhout the winter. At the latter season Ducks 

 of various species are regular visitors. Some of these, 

 however, keep well off the land out at sea, only enter- 

 ing the river mouths during rough weather, or at 

 night for the purpose of feeding in the shallower 

 water. One of the most familiar, perhaps, is the 

 JScaup; the Pochard is another, with a much more 



