MU. J. n. GURNEY ON OUNITIIOLOOICAL MIGR.ATIONS. 
53 
U.S any literature wliich is extant.^ Why tlien are we still so 
ignorant about it? I think any one who fairly considers the subject 
will admit that one of the chief reasons is, because the mass of 
facts which are recorded in our Natural History journals have 
never been properly tabulated, or rather, I should say, no attempt 
lias ever been made to tabulate them in any way. Let me merely 
refer to the ‘ Zoologist ’ and to the ‘ Field ’ newspaper, containing 
a multitude of observations, and the “ lleports on the ^Migration of 
Jiirds” now annually published, as exemplifying wdiat 1 mean. 
Although it may seem like shirking the (luestion to call it instinct, 
science can as yet give no better solution to the mystery of 
migration. 
The theory of migration by sight is open to many objections. 
Perhaps it is intended that we never should unravel the mighty 
mystery. Enough for us to .say with the author of the Look of 
dob, “ Doth the Hawk fly by thy wisdom, and stretch her wings 
towards the south?” (Job xxxix. 2G), and leave it in llis hands, 
Who gave to each animal the attributes proper to its nature. 
On fine starlight nights migratory birds fly high, but if dark 
and misty they are taken at lighthouses, and this circumstance is in 
favour of migration by sight. More birds than we think for 
migrate by day. As corroborative evidence, we may remember 
the extraordinary acuteness of vision of the Vulture and Peregrine 
Falcon in discerning their prey. Again, there is the opinion which 
generally obtains on the subject in tiie case of Pigeons: for experts 
consider that the Homing Carrier is undoubtedly guided by sight, 
coupled with memory of prominent objects it has seen before. It 
will bo readily admitted that numerous instances prove the vision 
of birds to be more acute than the most perfect human vision. 
On the other hand the opponents of this theory of sight sa}" : “ How 
can birds find their way over oceans and seas ? How, for example, 
can the Grey Crow, the Woodcock, and the Goldcrest, find the 
right path over the North Sea?” Sight would be of no avail here, 
even granting birds the most extraordinary powers, exceeding a 
hundredfold that of human beings. That birds arc hatched with a 
migratory instinct is proved l>y the efforts of captives to get out of 
their cages, which efibrts generally cease when the usual period 
* A list of the ancient classics, in which the subject is alluded to, will be 
found in Forster’s ‘ Observations on the Natural Ilistorj’ of Swallows ’ (p. 51). 
