168 THE BIRDS OF SHERWOOD FOREST. 
portion during the whole time it was being repaired, 
without exhibiting any alarm at the unusual proceed- 
ings. When all was finished, and her young ones 
restored, she flew around for some minutes, chirping 
cheerfully ail the time, as if expressing her thanks for 
the kindness shown her. 
The martin is much infested with a very disgusting- 
looking insect, as large, or larger, than the common bug. 
I have seen them swarm so thickly on some that the 
birds were rendered quite incapable of flight. I picked 
up one in this condition from the gravel walk in my 
garden. The poor thing manifested no alarm; buta 
glance told me the reason of this, as the bugs were creep- 
ing in and out of its feathers in numbers. I took it to 
the stream at the bottom of my garden, and got rid of 
its tormentors in the same way as the fox is reported to 
do. It seemed really grateful for the assistance, and as 
soon as the operation was completed flew off with the 
greatest alacrity. 
The next species, the Sand Martin (H. riparia), is, 
if possible, more subject still to these insect pests, and it 
is rather singular that two years after the occurrence I 
have just mentioned, I found in my garden a sand 
martin in a precisely similar condition, and freed it in 
the same manner. I have sometimes found their nests 
abound with fleas, and this was particularly the case 
with a group of some twenty nests which had been 
excavated in the sides of a shallow gravel pit in the 
forest. The pit was not more than five feet deep on its 
steepest side, and the holes were formed in a stratum of 
slightly hardened sand, which was only ten or twelve 
inches beneath the heather-covered surface of the 
ground. At least a third of these had been abandoned ; 
