BREWSTER’S WARBLER. 63 
remote degree the cries of young Chipping Sparrows at a certain stage in their 
career. But there were none of these birds in the swamp to confuse one. 
With this clue to the whereabouts of one of the families sought, a cautious 
approach would reveal one or both of the parent birds in their continual and 
indefatigable pursuit of food for the chirruping young. The source of the food- 
supply was to some extent the foliage of the tall trees overhead, but chiefly the 
undergrowth of ferns and Raspberry vines. At first the life of the young birds 
was passed exclusively in the dense herbage and shrubbery near the ground, 
but by the twenty-sixth of June they had acquired strength and confidence 
enough to make occasional sallies into the trees, soon to return to their favorite 
haunt on the ground below. Here they would take frequent short flights of two 
or three rods, from cover to cover, displaying in their course the obvious white 
markings of the tail feathers. By standing perfectly still, sometimes on the 
vantage ground of a small hillock or stump, I would from time to time get a 
good view of one or another of the brood. When Dr. Tyler was with me, we 
would sometimes adopt the following method of getting a close observation of 
the young birds: one of us would sit upon the ground, completely hidden in the 
Cinnamon Ferns, while the other would slowly drive the little birds toward the 
place of concealment. By this ruse we now and then succeeded in getting 
observations at a marvellously short range, so short, indeed, that I had to discard 
my field-glasses and put on my reading-glasses. 
On the approach of the parent bird with food, the youngling would receive 
it with accelerated chirps and quivering wings. In the intervals between the 
visits of the parents the young would condescend to a little listless gleaning 
of food for themselves, at least after they were a few weeks old, but this did not 
seem to moderate in the least degree their demands upon their parents. 
During some of our visits to the swamp we had all*three of the families. 
under observation within the space of two or three hours. As has been already 
pointed out, keys for the identification of the different families were furnished 
both by the adult and the young birds. In the group to which the nest belonged 
the father, a chrysoptera, was so much brighter in color than the father of the 
second family that he could be recognized at a glance; the young, moreover, 
were older and ever in a more advanced state of plumage. The third family 
was identifiable by the mother’s being a chrysoptera and the young ones also 
chrysopteras, with dusky throats and ear-coverts, whereas both the other broods 
had leucobronchialis mothers and, with the exception of one individual of the 
second family, lacked the diagnostic markings of chrysoptera. 
