12 MICHIGAN BIRD LIFE. 
A few years ago we might have included in this list the Wood Duck and the 
Woodcock, both of which had become very scarce and were believed to be 
in imminent danger of extinction; fortunately, however, these two birds 
seem to be no longer decreasing, and there is reason to hope that they may 
again become fairly common. 
Of course there are scores of other species which have decreased greatly, 
and some of them may be exterminated eventually before those just named. 
Almost every so-called game bird and water fowl is far less abundant than 
formerly, and nothing but a general recognition of the danger and wise 
legislation coupled with hearty and universal support can prevent their 
final extinction in the not distant future. The eight birds just named, 
however, at present seem to be those in greatest danger. The supposed 
causes of their decrease are discussed at length in connection with the life 
history of each species, so that we need not go into details here. It may 
be well to note, however, that five separate, yet more or less connected factors, 
have been operative in affecting the numbers of our birds; namely, the gun, 
the axe, fire, the drain, the plow. Of these by far the most important agent 
for decrease has been the gun, and its influence is steadily increasing. Axe, 
fire and plow form a trio of destructive and reconstructive agents which 
perhaps are now near the maximum of their combined power, though the 
sound of the axe has been growing steadily fainter for twenty years past. 
The drain and the plow are still powerfully affecting our bird fauna, un- 
questionably lessening the number of species, but just as surely increasing 
the total bird population through the increased food supply and better 
protection during the nesting season. 
With the exception of the Pileated Woodpecker, whose decrease depends 
directly on the removal of the forest, probably no one of the eight species 
now in danger has reached its present condition through the action of any 
single factor among those named. The Greater Egret, never common, has 
decreased steadily with other members of its family as the swamps have been 
drained and the use of the gun become more common. The Sandhill Crane 
has been a favorite mark for the rifle, its flesh forms palatable food, and its 
nesting grounds have been lessened through drainage. The disappearance 
of the Knot and Curlew is not fully explained, but is partly, though not en- 
tirely, due to the gun; neither species, however, nests within our limits and 
doubtless some factor operative on the nesting ground is largely responsible 
for the decrease. The Upland Plover has been rigorously followed as a game 
bird, but the cultivation of the prairies and pastures in which it loves to 
nest is partly responsible for its steadily failing numbers. Much the same 
causes have aided the disappearance of the Prairie Chicken, although the 
drain, the plow and fire have all been operative. The case of the Raven is 
unique. It certainly retires before advancing civilization, but precisely 
for what reason we are unable to say. The territory which seems to become 
untenable for the Raven is at once fully and safely occupied by the Crow, 
a near relative and of similar habits. Of late years, especially in the Upper 
Peninsula, the remaining Ravens have been largely killed by poison intended 
primarily for wolves. 
HOW TO STUDY BIRDS. 
The study of birds, like any other study, has two main objects, first, to 
acquire additional knowledge of facts; second, to increase the power of gaining 
knowledge. The lover of birds wishes to increase his knowledge of them, 
