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as elsewhere. Now it follows if these supposed augmentations 

 of sight and endurance were peculiar to the ordinary migratory 

 periods, that these supplementary movements would have to be 

 made without their aid. They are not, however, observed to be 

 conducted in any different manner to the seasonal nights. 

 During the prevalence of fogs, conditions are necessarily quite 

 unfavourable to any ordinary vision. Whilst it may be denied 

 that the powers of sight possessed by birds during the periods of 

 migration are augmented beyond ordinary times, it may be 

 readily granted that the speed of flight they put forth may be 

 considerably greater than that during the ordinary courses of their 

 lives. But that at the latter period this speed is not always at 

 their command, or, at any rate, is not increased by any special 

 change in their organisation at the former time, must, in the face 

 of the clearest evidence, be accepted as a fact. When a Plover 

 or other species, capable of very rapid flight, is attacked by a 

 Falcon it naturally exerts itself to the utmost to escape, and a 

 wonderful increase in the speed of its flight is apparent ; but as the 

 Falcon still gains upon its prey, the latter has recourse to twist- 

 ing and turning, simply because the limit of its speed has been 

 reached, and is, in many cases, of no avail. Under the influence 

 of fear it is natural that a bird will exert itself to the very utmost, 

 and may attain to a marvellous velocity of flight. It may also 

 be granted that at the periods of migration similar efforts may 

 be made, but nothing that has yet been witnessed in an encounter 

 between a Falcon and its prey can be said to approach to the 

 tremendous velocities attributed to certain small species during 

 their annual flights, according to the theories of Herr Gatke. 



In commenting on the evidence furnished by the speed 

 attained by domestic Pigeons, as illustrative of the powers 

 known to be possessed by birds, Herr Gatke has, to the writer, 

 fallen into a very simple error. Accepting the statement that 

 100 geographical miles an hour was accomplished by a Carrier- 

 Pigeon from Ghent to Eouen as accurate, he remarks, in com- 

 paring the possible powers of the progenitor of the latter, i.e., 

 the wild Bock-Dove : " It cannot be doubted that the flight 

 capacity of the domestic form must have fallen far short of that 

 of its primitive wild ancestor." This, he thinks, must be the case 



