Instinct is one thing, the migratory impulse another: we must also take into account, when considering the migration of birds, except the very young, the wonderful powers of memory displayed by animals. Those who are accustomed to ride and drive much, must have noticed how rarely a horse forgets any road he has once travelled, or any house he has stopped at, it may be years previously. Out of many instances, I will mention one of this memory in birds. In 'The Zoologist' for 1875, p. 4698, Mr. Nicholls, writing from South Devon, mentions the case of a young Herring Gull taken from the nest in May, 1871, and brought up in a state of domestication. In May, 1872, it left its quarters, and was given up as entirely lost, but, strange to say, in November, 1873, it returned, then in beautiful plumage, and allowed its old friend and playfellow, a little boy of eight years old, to take the same familiarities with it as formerly.
The migratory seasons are undoubtedly the most important periods in the life of a bird: without these regularly recurring periods life would be impossible for them; their existence and the continuation of their race is dependent on these annually recurring voyages through the air. If, then, the instinct has been so strongly and rapidly developed in birds in the case of the paper kite and telegraph-wires, how much stronger may we suppose it to be in guiding the bird along its air-path towards that bourne which countless generations of its kind have sought before.
Enough I think has been said to prove the untenabilily of this new automaton hypothesis. Indeed, the more it is considered the more absurd does it appear. Nothing short of a miracle would be required to cause a gust of wind to take the same Stone Curlew, in the case above cited (and it is impossible it could have been otherwise than the same bird), year after year, from its winter quarters somewhere in Africa and set it down in its former nesting haunt in what is now the middle of a Suffolk wood.
