POT 
AGRICULTURAL AND HORTICULTURAL SOCIETY. 67 
interesting investigations as to the value of birds as one of the surest 
means of remedying, and indeed the only effectual means of meeting 
some of its various forms. ‘lhe French government has been especially 
active and the investigations that have been carefully and persistently 
made under its patronage, have been of the highest value. M. Florent 
Prévost has been at the head of the investigations, and has so devoted 
himself to them as to make them the great mission of his life. I have 
studied his reports, and give full faith to the general laws and principles 
which he has educed from his long continued investigations, that cover 
a space of a third of a century. They may all be summed up in this 
comprehensive and sententious dogma: ‘ No agriculturist can take the 
life of any bird without doing that which can result only in loss to 
himself.” I believe that in this he is entirely right. Every bird has 
its mission of good, though we may not now see it. 1 do not ask or ex- 
pect you to go so far as this in the present state of our knowledge. It 
may yet be a long while before we shall be educated to a full knowledge 
of the value of this standing army, this feathered host of nature’s con- 
stabulary who stand as her great counterpoise between the insect powers 
of destruction and the fruits of the earth. M. Prévost has demonstrated 
beyon 1 all dispute, that all birds are more or less insectivorous — that 
those we generally regard as insect-eating birds especially, do not, as a 
general thing, destroy those insects that do us the most harm, and that, 
for the most part, the birds which render the most effectual services in 
destroying the most noxious insects, are birds against which popular 
prejudices are the strongest, The sparrows, the starlings and crows are 
the great destroyers of the cockchafers, as our crows and blackbirds 
are of the May-beetles, and we are ¢at just finding out that many 
birds we have deemed to be our enemies are really our best friends. 
Another most important law of nature revealed by M. Prevost’s in- 
vestigation is of especial interest. This is, that all birds, during the 
period of reproduction, whatever may be their natural food at other 
times, are almost entirely insect-eaters, and that they feed their young 
almost exclusively with insect food. Then the amount of insect food a 
young bird will consume ina given time is enormous. Dr. Wyman 
took from the crop of a young pigeon, a mass of canker-worms, that 
was more than twice the weight of the bird itself; and it is shown by 
Prof. Treadwell, that a young robin will eat, and require too, for his 
well-being, at least his own weight in insect food. On less than this 
he cannot live twenty-four hours. 
