DUNLIN. 611 



on the mud flats of the Tees and Humber estuaries a great 

 influx of immigrants takes place in mid- August, frequently 

 continuing to arrive throughout October. In very severe 

 weather many of these leave for more southern quarters, 

 though vast numbers make Yorkshire their winter home, 

 and may be seen on the " slems " and sands, or performing 

 their aerial evolutions at high tide. 



A return movement takes place in April and May, often 

 in company with Ringed Plovers and other northward 

 travelling waders ; some linger at the estuaries as late as June, 

 and a few non-breeding birds in partial summer plumage 

 remain during the summer ; on 2ist June 1899, a pair was 

 observed at Hornsea Mere in Holderness. 



The Dunlin is frequently found amongst the victims 

 lured to their destruction by the rays of our sea-beacons, 

 and on calm evenings in autumn I have many times listened 

 to the calls of birds passing overhead on migration. 



A divergence of opinion exists in reference to the question 

 of the different races of this species, and I may state that my 

 experience on this point shows that our nesting birds in- 

 variably belong to the small bright-coloured form ; both 

 the large and small varieties appear on the spring and autumn 

 passages ; I have shot examples of each kind from the 

 same flock in September, and am strongly of opinion there 

 are two races, but doubt whether the differences in size are 

 sufficient to constitute specific distinctions ; they are more 

 likely attributable to the influences of climate and food. 

 Measurements of the two forms, taken from Yorkshire speci- 

 mens, are set forth by Mr. J. Backhouse, in the Zoologist 

 (1901, pp. 91, et seq.). 



On all the sandy beaches between the Tees and Humber 

 the Dunlin occurs more or less frequently, generally whilst 

 on its migrations, at these periods being also observed in 

 small parties at localities far distant from the coast. 



Nidification commences early in May on the low grounds, 

 being a week or two later in the fell districts. Though most 

 authors agree that the nest is very difficult to discover, it may 

 be worth mentioning that one, found at the Teesmouth in 



