MIGRATION 567 
what is called the “homing” faculty in Pigeons might furnish a 
clue, but Mr. Tegetmeier and all the best authorities on that sub- 
ject declare that a knowledge of landmarks obtained by sight, and 
sight only, is the sense which directs these Birds, while sight alone 
can hardly be regarded as affording much aid to Birds—and there 
is reason to think that there are several such—which at one stretch 
transport themselves across the breadth of Europe, or even traverse 
more than a thousand miles of open ocean, to say nothing of those 
—and of them there are certainly many—which perform their 
migrations mainly by night. That particular form of BLUETHROAT 
which yearly repairs to breed upon the mosses of the Subalpine 
and Northern parts of Scandinavia (Cyanecula suecica) is hardly ever 
seen in Europe south of the Baltic.’ Throughout Germany it may 
be said to be practically absent, being replaced by a conspicuously 
different form (C. leucocyana), and as it is a Bird in which the 
collectors of that country, a numerous and well-instructed body, 
have long taken great interest, we are in a position to declare that 
save in Heligoland, it is hardly known to stop in its transit from 
its winter haunts, which we know to be Egypt and the valley of 
the Upper Nile, to its breeding-quarters. Other instances, though 
none so crucial as this, could be cited from among European Birds 
were there room here for them. In New Zealand there are two 
Cuckows which are annual visitors: one, a species of Chiysococcya, 
probably has its winter quarters in New Guinea, though commonly 
supposed to come from Australia, the other, Hudynamis taitensis, is 
widely spread throughout Polynesia, yet both these birds yearly 
make two voyages over the enormous waste of waters that sur- 
rounds the country to which they resort to breed. But space 
would utterly fail us were we to attempt to recount all the ex- 
amples of these wonderful flights. Yet it seems impossible that 
the sense of sight should be the faculty whereby they are so guided 
to their destination, any more than in the case of those which 
travel in the dark. 
Dr. von Middendorff (Jsepipt. Russl. p. 9), from the conclusions 
he has drawn, as before mentioned, as to the spring-movement of 
all birds in the Russian Empire being towards the Taimyr Penin- 
sula, the seat of one of the magnetic poles, has suggested that the 
migrating Bird is always aware (he does not exactly explain by 
but if that objection be raised the circumstance becomes still more puzzling, for 
then we have to account for some mode of communicating precise information by 
one bird to another. 
1 It has occurred indeed as a straggler in spring about a dozen times in 
England, and it arrives twice a year in greater or less numbers in Heligoland as 
reported by Herr Gitke. Its autumnal visits to this country, occasionally in 
considerable numbers, seem to be almost annual, though of course they are not 
always observed. 
