MIGRATION 557 
consider that the majority of observations have been made towards 
what is the northern limit of the range of the Passeres, to which the 
remark is especially applicable—in the British Islands, France, 
North Germany, and the Russian Empire—for it is plain that at 
the beginning of the journey any inequality in the speed of travel- 
ling will not have become so very manifest. There is also another 
matter to be noticed. It has been suspected that where there is 
any difference in the size of birds of the same species, particularly 
in the dimensions of their wings, the individuals that perform the 
most extensive journeys are naturally those with the longest and 
broadest remiges, and in support of this view it certainly appears 
that in some of the smaller migrants—such as the WHEATEAR (Sazicola 
enanthe) and WILLOW-WREN (Phylloscopus trochilus)—the examples 
which reach the extreme north of Europe and there pass the summer 
possess greater mechanical powers of flight than those of the same 
species which stop short on the shores of the Mediterranean. It 
may perhaps be also inferred, though precise evidence is wanting, 
that these same individuals push further to the southward in winter 
than do those which are less favoured in this respect. It is pretty 
nearly certain that such is the case with some species, and it may 
well be so with individuals. Canon Tristram has remarked (Ibis, 
1865, p. 77) that, in many genera of birds, “those species which 
have the most extended northerly have also the most extended 
southerly range ; and that those which resort to the highest latitudes 
for nidification also pass further than others to the southward in 
winter,” fortifying his opinion by examples adduced from the genera 
Turdus, Fringilla, Cypselus, and Turtur. But supposing this to be 
true for many Birds, it may fairly be doubted whether it is so for 
all, and whether in some species certain individuals do not always 
occupy the most northern portion of the range and others always 
keep to the most southern, no matter what the season of the year 
may be, or over what countries the range may extend. On this 
point therefore it will be advisable to await further investigation. 
For many years past a large number of persons in different 
countries have occupied and amused themselves by carefully register- 
ing the dates on which various migratory Birds first make their appear- 
ance, and certain publications abound with the records so compiled.! 
Some of the observers have been men of high scientific repute, others 
of less note but of not inferior capabilities for this especial object. 
Still it does not seem that they have been able to determine what 
connexion, if any, exists between the arrival of birds and the state 
1 These are far too numerous to mention here. Perhaps the most remarkable 
series of them is that carried on from 1736 to 1810 and again from 1836 to 1874 
by four generations of the Marsham family at Stratton-Strawless and Rippon 
near Norwich, of which an account is given by Mr. Southwell (Z'rans. Norf. & 
Norw. Nat. Soc. ii. p. 31), 
