190 THE ZOOLOGIST. 



inclined to think that these large flocks were very leisurely moving south- 

 wards for the winter, influenced a good deal by the winds and the plentiful- 

 nessof food. In southward migrations it is by no means uncommon for a 

 certain proportion of old birds to accompany the first flights. In fact, the 

 experience of a good many autumns on the Yorkshire coast has shown me 

 that the first Grey Plovers, for example, to appear are old birds in small 

 parties, still more or less in summer plumage. And the same with Sander- 

 lings and Curlew Sandpipers. — Henky H. Slater (Wansford). 



Sandwich Terns on the Upper Thames. — A visit from eight adult 

 Sandwich Terns, on April 10th, was quite a novelty to this neighbourhood. 

 They arrived before 9 a.m., and the greater part of the day was spent 

 exactly opposite this house, sitting on the hand-rail of the bucks and the 

 piles on the weir. The day was warm and bright, with a fresh westerly 

 breeze, and the Terns were careful always to sit facing accurately to wind- 

 ward. At frequent intervals one or more would take short flights, in beats 

 of perhaps 100 yards, in quest of fish, for which they plunged down from a 

 fair height, with the wings about two-thirds expanded, and always side to 

 wind. Early in the afternoon they moved half to three-quarters of a mile 

 further up the river, where, there being no convenient perches, they spent, 

 I believe, their whole time on the wing. About 4.45 p.m. six of them 

 returned to the rail and piles on Marlow Weir; whether the other pair had 

 separated voluntarily, or whether powder and shot had put an end to their 

 wanderings, I do not know. During the morning any attempt by a second 

 bird to share a pile already occupied by one had been successfully resented 

 by the tenant, but now a pair shared a pile more than once, and they com- 

 bined to prevent the intrusion of a third individual. I did not see them 

 leave, but I satisfied myself, with the help of a good night-glass, before 

 going to bed, that they were not roosting on the piles or elsewhere there- 

 abouts, and have not seen or heard of them since. The Common Tern is 

 entitled, I think, to be classed as an annual visitor to the Upper Thames, 

 and the Little and Black Terns are also frequent visitors. The Arctic 

 Tern, which is recorded in Clark-Kennedy's ' Birds of Berks and Bucks ' 

 as " occasionally obtained " in these counties, I have never myself seen on 

 the river, or at least distinguished from Sterna fluviatilis ; while the Sand- 

 wich Tern is not mentioned by him. Mr. Aplin, in his 'Birds of Oxford- 

 shire,' mentions it as " a rare visitor," and enumerates about six examples 

 obtained in the neighbourhood of Oxford between 1847 and 1879- These 

 may all have come from the West, and did not necessarily pass this neigh- 

 bourhood ; while it seems natural to suppose that those which lately visited 

 Marlow flew up wind from the mouth of the river. Another point notice- 

 able about this visitation is the number of birds which appeared, forming 

 the largest party of sea-birds that I have ever seen up the river, where such 

 stragglers usually appear singly. — Alfkkd Hkneage Cocks (Great Mar 

 low, Bucks). 





