442 THE BIRDS OF HELIGOLAND 



the birds which had just begun their breeding occupations, as to 

 compel them to resume their spring migration after the manner of 

 other southern and south-eastern species. Such birds, if they did not 

 at once alight upon districts offering them the requisite conditions 

 for nesting, would then travel beyond the limits of their natural 

 home ; their extraordinary capacity for flight would, in fact, convey 

 them in a few days to countries four thousand miles distant. 



The ovaries of Sand Grouse which were taken here at the 

 beginning of May contained only very small eggs about the size 

 of a No. 5 shot. Now, according to Radde (Reise im Suden von 

 Ost-Sibirien, ii. 287), these birds begin to breed as early as April, 

 and therefore one is led to suspect that these exceptional migratory 

 hordes consisted of individuals whose first clutch of eggs had been 

 destroyed. 



As has been already intimated, the velocity of the flight of these 

 birds is truly astonishing. In whatever high esteem the noble 

 Falcon is held in this respect by Heligolanders, all of them are 

 agreed, without exception, that this bird would not be able to over- 

 take a Sand Grouse. The rapidity of their flight is particularly 

 remarkable in cases where large flocks cross the sea at a considerable 

 distance from land ; hardly have such birds approached within the 

 vicinity of one's boat before they are again lost sight of on the 

 distant horizon. I do not entertain the least doubt that cases may 

 have occurred in which they have crossed the North Sea between 

 Jutland and England several times in one day. 



In Heligoland the birds resort by preference to the base of the 

 sand-hills or dunes on Sandy Island, where it is hardly possible, 

 so long as they remain quietly on the ground, to discover them 

 among the sand and variously-coloured shingle. Amongst the con- 

 tents of their stomachs I have found, in most cases, only the seeds of 

 wild plants, very rarely a few grains of wheat or barley, but rather 

 frequently the seeds of the sand lyme-grass {Elymus arenarius) ; 

 sometimes, again, only grass cut up into fine bits ; also sand-grasses 

 and other shore plants, always mixed up with a quantity of small 

 grains of quartz. In several cases, too, I found a number of sea- 

 snails, such as Littorina littorea and L. obtusata; but in no instance 

 did the stomachs which I examined contain the remains of beetles 

 or other insects. 



This interesting bird occurs as a resident breeding species in the 

 sandy steppes of Asia, from Turkestan to China, and is especially 

 abundant in the desert tracts of Mongolia. 



