370 NORTH AMERICAN BIRDS. 



were moving northward. These could, at a long distance, be readily distin- 

 guished from flocks of water-fowl or waders, by their flight being in no par- 

 ticular order. On the Mackenzie, Mr. Eoss observed these birds as far north 

 as Fort Norman in latitude 65°, while on the coast of Hudson's Bay they 

 are only found as far as 58°, even in warm summers. 



The Wild Pigeon appears to be almost entirely influenced in its migra- 

 tions by the abundance of its food, excepting in those parts of the country 

 in which it has not been known to remain during winter. Even in these 

 movements it is largely influenced by instinctive considerations of food. 

 Evidently the temperature has but little to do with their migrations, as they 

 not unfrequently move northward in large columns as early as the 7th 

 of March, with a thermometer twenty degrees below the freezing-point. In 

 the spring of 1872 a large accumulation of these birds took place early in 

 March, in the eastern portion of New York. They were present in the 

 forests about Albany, and were taken in such iuimense numbers that the 

 markets of New York and Boston were very largely supplied with them. 



As early as the 10th of March they were ascertained to have in tlieir ova- 

 ries full-grown eggs, ready for exclusion. In Kentucky they have been 

 known, according to Audubon, to remain summer and winter in the same 

 districts for several successive years, in consequence of the great abundance 

 of food, while in other parts of the State none were to be met with. They 

 suddenly disaj)peared as soon as the beech-mast had become exhausted, and 

 did not return for a long period. 



The Wild Pigeons are capable of propelling themselves in long-continued 

 flights, and are known to move with an almost incredible rapidity, passing 

 over a great extent of country in a very short time. It is quite a common 

 and well-ascertained fact that Pigeons are captured in the State of New York 

 with their crops still filled with the undigested grains of rice that must have 

 been taken in the distant fields of Georgia or South Carolina, apparently 

 proving that they must have passed over the intervening space within a 

 very few hours. Audubon estimates the rapidity of their flight as at least 

 a mile a minute. 



The Wild Pigeons are said to move, in their flight, by quickly repeated flaps 

 of the wings, which are brought more or less near to the body, according to 

 the degree of velocity required. During the love-season they often fly in a 

 circling manner, supporting themselves with both wings angularly elevated. 

 Before alighting, they break the force of their flight by repeated flappings. 



Their great powers of flight, and the ability thus given to change at will 

 their residence, and their means of renewing a supply of food, are also thought 

 to be seconded l)y a remarkable power of vision, enabling them to discover 

 their food with great readiness. Mr. Audubon states that he has observed 

 flocks of these birds, in passing over a sterile part of the country, fly high in 

 the air, with an extended front, enabling them to surve}^ hundreds of acres 

 at once. When the land is richly covered with food, or the trees well sup- 



