248 MICHIGAN BIRD LIFE. 
As to the cause or causes of the disappearance of the Passenger Pigeon 
the greatest diversity of opinion exists. Most naturalists agree that man’s 
warfare upon the bird on its nesting grounds has been the prime cause of 
its extinction; but there are not wanting those who refuse to admit this, 
and it seems perfectly certain that other causes must have combined to 
effect. the complete extermination. Some believe that the development of 
some unknown but deadly parasite was responsible for the death of the Pigeon 
host, and it is pointed out that the gregarious nature of the birds would 
favor the increase and spread of such a parasite, which might naturally 
pass through a cycle which would culminate in the practical extermination 
of the Pigeon. There is, however, not a particle of direct evidence to 
support this theory. A similar theory ascribes the sudden disappearance 
to some unknown disease. 
The fact that during sudden and heavy storms, and particularly during 
foggy weather and snow storms, hundreds and perhaps thousands of 
pigeons have been drowned in the waters of the Great Lakes gives color 
to the supposition that the last remaining bands of pigeons may possibly 
have perished in this way. Unquestionably the clearing away of the great 
pine and hardwood forests of the north has been very largely responsible 
for the rapid decrease, since this removed their principal food supply of 
beech nuts, acorns and the seeds of various conifers, and these areas, recently 
cleared by the lumberman’s axe, were almost invariably devastated soon 
after by fire, which in some cases swept over entire counties and left 
hundreds of square miles a barren wilderness. 
In the opinion of the writer the most probable cause of the disappearance 
of the pigeon lies in the fact that, through this clearing of the forests and the 
increasing persecution by man, the birds were driven from one place to 
another and gradually compelled to nest farther and farther to the north, 
and under conditions successively less and less favorable, so that eventually 
the larger part of the great flocks consisted of old birds, which, through 
stress of weather and persecution, abandoned their nesting places and 
failed to rear any considerable number of young. Under such conditions 
they would naturally become weaker, or at least less resistant, each year, 
and in the attempt to find nesting places in the far north they may have 
been overwhelmed by snow and ice during one or two of the unusually 
severe summers which occurred between 1882 and 1890. 
Many attempts have been made to domesticate the Wild Pigeon and the 
birds have proved hardy in captivity and have nested somewhat freely; 
yet no domesticated race has ever been established, and so far as can be 
learned not more than two individuals of this species are now living 
in any zoological garden or aviary in the world. Audubon sent living 
specimens to a British nobleman, the Earl of Kirby, as early as 1830, and 
they lived and bred for many years, but seem to have died out eventually. 
Mr. David Whittaker of Milwaukee, Wisconsin, secured a pair of young 
Passenger Pigeons from northeastern Wisconsin in the fall of 1888, and in 
the course of eight years succeeded in breeding from them a little flock of 
fifteen birds, six males and nine females. Many eggs were laid each year, 
but few of the young which were hatched could be reared, apparently for 
lack of proper food. This flock was divided, part of it going to Dr. C. O. 
Whitman of Chicago University, who in 1904 had ten birds, but thought 
they had been much weakened by inbreeding, as few of the eggs were fertile 
and the flock steadily decreased. The following year only four were left. 
Meanwhile the original Milwaukee flock had decreased in the same way, 
