SUMMER VISITORS 107 



from which the summer visitors come ; climatic conditions ; within a day or 



but if we take the analogy of the com- two days, a gradually rising tempera- 



mon winter visitants, it is probable ture appeared to have some influence on 



that the weather in the place of winter the dates of arrival, but only such as 



residence is one of the main factors, could be accounted for by the enhanced 



Algiers and other winter haunts of ease of the long journey ; and that as 



our summer nesting birds do not be- regards the wind, at any rate, no 



come suddenly inclement in spring, connexion could be found, since whether 



but probably the approach of increased it was dead against the travellers or 



heat is just as unwelcome to these birds fair and square astern, not a tittle of 



as the approach of extreme cold is to difference in time could be proved. For 



those species which nest in Scandin- instance, in five consecutive years, 



avia, and flee before their severe winter the first ring ousel was notified on 



to Great Britain and the coasts of the March 20, under widely varying wea- 



Mediterranean. An organization of ther conditions ; or to take a much 



naturalists has endeavoured during smaller and weaker bird, the chiff- 



the past ten years to prove that a late chaff annually arrives as nearly as 



spring delayed the great army of mi- possible on March 17, again irrespec- 



grants in any one species, but found, tive of wind or weather ; and so on. 



both by its own observations and by Further, the swift, which is probably 



bribing or persuading lighthouse keep- the strongest-winged bird of all that 



ers to send the wings of any birds nest in Great Britain, sturdily arrives 



that flew against the lantern glasses last of all and leaves earliest, with an 



and were killed, that the earliest arri- entire disregard of weather conditions 



vals in each species were found on the such as only a Scotch shepherd could 



coast on practically identical dates in hope to emulate, 



each year ; that the main body of the Again, different species have their 



migrants in any given species arrived well defined and preserved points of 



about the same time in each year in- entry to the country. Five species , 



dependent of wind or weather condi- the ousel, garden warbler, sandpiper, 



tions ; that in the case of species which swift and corncrake' have a marked 



immigrated in great flocks or droves at objection to landing east of Southamp- 



intervals of several days, these flocks ton. The obvious retort would be 



preserved those intervals unaffected by that they all winter in a western con- 



