ROM time to time we hear much of the immigration of aliens to this country. 
It would be interesting if some of our industrious statisticians would show us 
in figures of number and £ s. d. the results for good or evil of that greater movement 
of aliens to our shores that sets in with unfailing regularity at certain seasons of the 
year. Some of the visitors come to keep up the vigour, and improve the strain by 
crossing, of many of our direst insect foes. Others, as the nightimgale, are popularly 
thought to come solely for the purpose of making our woods perfect with song at just 
that period of the year when we can best enjoy an evening stroll beneath the boughs. 
But not all these songsters are aliens, for many of them first saw the light in the 
very woods to which they have returned after an eight months’ absence. 
Among those philanthropic migrants who come for nothing we ourselves value 
or want, and who do nothing but good to us throughout their brief sojourn, must be 
reckoned that weird bird, the Nightjar; and he must be put in the front rank of our 
friends. From the day of his arrival in May until his return to North Africa in 
September, he wages war upon certain of our enemies which constitute his entire food. 
He does his work, too, in the evening, when there are no other creatures to speak of 
preying upon the moths and beetles that fly at twilight. It cannot even be alleged 
against him that he makes us pay for his help by taking toll of our fruits and seeds; 
he is strictly insectivorous, though an ancient slander charges him with milking goats. 
Country folk who live on the borders of woods and heath-clad moors regard him as 
something uncanny, and really this is not to be wondered at. heir ideas have to 
some extent been embodied in the local names they have bestowed upon him. It Is 
clear from these that they have had some difficulty in placing the bird in their 
rather elementary systems of classification ; 
but they have done their best. Because of 
the small portion of beak that projects 
from the abundant plumage they have 
been tempted to place him among the 
owls, and have called him fern-owl and 
churn-owl. Because of his size, his barred 
and mottled feathers and his flight, they 
have styled him a hawk—night-hawk and 
