TIIK RIRD.S OF IIELIOOLAND 501 



nunicroiisly, several iiHli\ Iduals having been shot; on the 18th, in 

 still lar<,'er number, while on the 20th only solitary individuals or 

 strasjsilcrs were met with. 2'. arenarui was seen on the 10th and 

 20th of June. Of Gharadrius hiaticida, which breeds on the 

 island, the first individuals arrived on June 1 Ith ; from that date 

 the bird was rai"e, until the 20th, when it a[)[)cared in numbers. 

 [n the case of G. fulvus, which also breeds on the island, the first 

 individual was scon on the 12th of June; several were observed 

 on the 14tli, and large nund)ers on the 20th. Of G. helvctivus a 

 pair was noticed on the 19th, but its numbers were increased on 

 the 20th. This 20th of June seems in fact to have been a day 

 specially favourable for migration, for parallel facts are repeated 

 in the cases of many other species — e.g. Pludarojyua, Lestris, and 

 Anaa. It is further a noteworthy fact that on this particular day 

 the migration of species whoso breeding homes lie to the north of 

 the island either diminishes or ceases altogether, while that of species 

 which have remained to breed, such as 0. hiaticula and C. fulvus, 

 rises in numerical proportion. 



In Heligoland the Knot is of rather rare occurrence during 

 the spring migi-ation. In the course of May a bird may be met 

 with occasionally on the dune ; but I had to wait a good many 

 years before I succeeded in obtaining a fine old individual in the 

 pure nujitial plumage. About the end of July old birds in much 

 faded summer plumage occur somewhat more frequently ; in 

 such individuals the beautiful rich ferruginous colour of the 

 neck and lower parts had pa.ssed into a light orange-buff (Ovawf/e- 

 rosUjelb) while the ferruginous spots on the feathers of the back 

 and wings have faded to a bufty-white ('ro.stgelJjllchem Weiss.). 

 This last colour is in sharp contrast with the glossy black 

 ground-colour of the feathers of the back and shovdders, so 

 that the bird still presented a strikingly beautiful appearance. 

 However, birds like these have certainly not returned from 

 breeding homes in the high north, but belong to the numerous 

 individuals which have passed an errant kind of existence during 

 the summer, largo numbers of which are found among nearly all 

 the species of shore-birds. 



Young birds of the year in the grey i)lumago occur numerously, 

 sometimes in fiocks on the shore of tlie dunes, throughout August 

 and the first half of September ; on the other hand, old birds in 

 pure winter plumage are of rather rare occurrence. Most of 

 these are killed in the earlier part of the year on the upper 

 plain of the island. 



The breeding range of this species has been already discussed 

 above ; its eggs have never hitherto been discovered. 



