JVofes from Nortli Ifolland. 167 



after if, tliero seems to me no great improbaLility in tliis 

 View. 



The qncstion o£ fat leads us to another ol the migration 

 Problems, namely, the length of joiirney undertaken at a stretch ; 

 and i£, as seeius probable, this large störe of fat is used iip 

 before ahy prolonged re.st or food is taken, the Journej must be 

 of no inconsiderable length. 



I often watched migratory flocks pass over the island going 

 dne west, sind suppowng they held to their course it would 

 necessitate a flight of at least 200 miles from coast to coast. I 

 quote this distance not becaiise I believe it to be excessive or 

 anything approaching the maxinium length of a single flight, 

 but merely because ray observations tended to show fairly con- 

 clnsively that such flights were undertaken. Much, of course, 

 depends on the rate of flight, a matter almost impossible to 

 determine accurately ; but from some very rough calcuhitions 

 based on individuals not migrating but passing along the shore, 

 I found that over a short distance a rate equivalent to 90 miles 

 an hour by no means unusual in the case of the Grey Plover. 



Among the Limicola^ the flocks consisted almost entirely of 

 young birds ; on my previous visit in August old birds of ccrtain 

 species — e. g., Golden and Grey Plover, Dunlin, Knot, Green- 

 shank — were not uncommon, but on my last visit hardly any 

 ■were to be seen. My notes of 1906, moreover, show that, with 

 the exception of tvvo specieSj the old birds outnumbered the 

 young in August, so that it seems more than likely that they 

 migrate first. The two cases in which the old birds did not 

 outnumber tho young were the Redshank (^Totamis calidris) 

 and the Dunlin (^Tringa alpina), both of which have. a more 

 southerly breeding-range than many of the other species, while 

 of the Ruifs (Machetes) and Black-tailed Godwits [Limosa) that 

 breed on the isLind no adults were seen ; so that the balance of 

 evidence is certainly in fuvour of the adults travelling first^ in 

 spite of Herr (^rätke's observations, which, in this instance, I 

 find difficult to reconcile with my facts. At the sume time it 

 shüuld be remembered th:it the adults seen in August may be 

 l)irds that have spcnt the sumnier without going north as we 

 Jcnow so many do. Whatevcr may be the reason, however, the 

 fact reinains that after the iniddle of September, at anv rate. 



