192 Henshaw on Causes affecting the Decrease of Birds. 
Old age among birds, as elsewhere throughout animated 
beings, is instrumental as a check on increase, and doubtless 
many birds survive the various dangers to which bird life is heir 
to and pay the last great debt from the decay of their vital 
powers. But the number of deaths from disease and old age 
doubtless varies within comparatively narrow limits, and hence 
either alone or combined with natural enemies cannot furnish the 
cause we seek. Of death-dealing causes none is so curious as 
that modern invention the telegraph wire. On the plains where 
high winds prevail and where there is insufficient shelter many birds 
have been noticed under the wires, dead or crippled from being 
blown against them. Under such circumstances it has proved 
a source of considerable mortality among small birds. But 
when the wires are first put up in a neighborhood it is by no 
means a rare accident for birds of various kinds to fly against 
them in calm weather, evidently not seeing, or at least not com- 
prehending, the nature of the obstruction. As might be expect- 
ed from the height at which it flies and the time of day when 
most active, the Woodcock is particularly prone to this sort of 
accident, and scores of this bird have been reported in the 
sporting papers as being found dead or disabled under newly 
laid wires. It bears witness to the intelligence of birds and 
their power to profit by the lessons of experience that in a very 
short time they learn to appreciate the danger and to avoid it by 
flying above or below the obstruction, so that they rarely suffer 
even in high winds. 
Storms, especially when they are prolonged and accompanied 
by sudden and excessive change of temperature, are directly 
responsible for important changes in the relative numbers in the. 
species of a district, and not a few instances could be cited where 
certain species have been entirely exterminated from a locality. 
The less hardy of our small Insectivores are specially liable to 
disasters of this kind, particularly in the spring, during or just 
subsequent to their return from their tropical winter quarters. 
Indeed, taking our country at large, it is probable that scarcely 
a year passes without the loss in one or several districts of great 
numbers of birds from this cause. Sometimes the storm-visited 
area is small, and occurring early in the season the storm works 
injury to comparatively few of the earlier migrants. But occa- 
sionally it is wide-spread in its effects and, coming in the height 
of the migration, destroys g^eat numbers of individuals and affects 
a considerable number of species. 
