32 BULLETIN 1245, U. S. DEPARTMENT OF AGRICULTURE. 
of such losses, and those are largely confined to the Northwest. 
There is no doubt that ferns will poison both cattle and horses, and 
probably sheep, and care should be taken that hungry animals do 
not have an opportunity to consume any large quantity. 
PREVENTION OF LOSSES. 
In Farmers' Bulletin 720 attention was directed to the fact that 
most of the losses from poisonous" plants occur at times when the 
animals are short of feed, and it was suggested that the larger 
part of the stock poisoning is indirectly due to scarcity of proper 
forage. This fact of the intimate relation of scarcity of feed to 
stock poisoning can not be too strongly impressed upon the people 
who handle range animals in the West. 
There is apparently a popular idea that range animals will volun- 
tarily seek out poisonous plants and eat them by preference. It may 
be stated as a general fact that this is not true. Animals seldom eat 
poisonous plants except as they are driven to do so by lack of other 
food. Almost all poisonous plants are actually distasteful to live- 
stock and under ordinary circumstances will be avoided. The only 
exception to this, perhaps, is the group of loco plants. Animals do 
frequently acquire a taste for loco and under some circumstances will 
eat nothing else, even in the presence of other forage; and yet the 
initial feeding in the case of loco plants is almost invariably brought 
about by scarcity of food. 
It has long been known that loco eating is ordinarily commenced 
in the winter season or in the early spring when the loco plants are 
green and luscious, and before the grass has started. The loco plants 
at that time are the most prominent plants on the plains, and animals 
commence to eat them because of lack of other food. Many animals 
ufter feeding upon loco a short time acquire a liking for it and will 
continue to eat it even in the presence of an abundance of other food. 
This is not true, however, of all loco-eating animals, for there are 
very many which, after the grass has started, will leave the loco and 
will recover entirely from the effects which have been produced by 
the preceding feeding. 
In the matter of the other plants, the relation between starvation 
and the eating of the poisonous plant is still more marked. For 
instance, the larkspurs spring up immediately after the snow leaves 
the mountains and grow much more rapidly than the surrounding 
grasses, and if cattle are allowed to go to the upper ranges before 
the glasses have had a fair start, they find already occupying the 
ground the succulent larkspur plants in large numbers. Sometimes 
the cattle come from dry winter feed and are anxious to gorge them- 
selves with any green material they find. Under such circumstances 
if they come upon a field of larkspur they frequently eat enough to 
produce fatal consequences. Later in the season there is very much 
less danger from larkspur because of the abundance of other food. 
1 f. however, cattle are driven from one range to another and the trail 
passes through a mass of tall larkspur, it is not at all unusual for the 
hungry animals to grab hastily at the plants, and this may result in 
disastrous consequences. Under such circumstances it is important 
that the cattle shall not be driven rapidly, for if driven rapidly they 
