THE WREN. 19 
THE FALL MIGRATION OF THE TREE SWALLOWS. 
The past two falls, while I have been staying in Duxbury, I have 
come upon, quite unexpectedly, large migratory flocks of the Tree 
~ or White-bellied Swallows. Duxbury is, I think, an unusually 
favorable place for these birds, since it has an extensive salt marsh, 
bordered by a long stretch of sandy beach. The Tree Swallows 
are summer residents of the vicinity in small colonies; but in the 
fall, it would seem as if all the Tree Swallows of New England 
gather there for the southward flight. 
In 1907, on September 2, I noticed a tremendous flock of the birds. 
From a distance, as I approached the head of the marsh where a 
road with the ever-present telegraph wires crossed, the flock looked 
like a cloud of snow flakes. When I reached the road and stood 
still, they began to settle on the wires. Gradually the wires be- 
tween three successive poles filled up, until the birds landed on each 
other’s backs to get a place. All the while, they kept up a con- 
tinual twittering, and gossiping, and quarreling. There were ten 
wires and each wire for the distance between three poles was 
covered with Tree Swallows. An accurate count of the whole 
flock was impossible, owing to their restlessness, so I counted the 
birds along one wire and multiplied by ten. From this‘ rough 
estimate, I decided there were between 3000 and 4000 birds in the 
flock. As I watched them, an old farmer came along. He was a 
talkative soul and to emphasize the number of birds there really 
were, he told me the following yarn. He said that the day before, 
he had been out on the marsh with his flint-lock or some such 
antique fire-arm. ‘There was an old saddle out there covered 
with swallows. He fired the gun into the midst and killed 80 birds 
in one shot. ‘This story shows how numerous the birds were, 
although it is undoubtedly much exaggerated. It shows, too, the 
need of enforcing the laws to protect valuable birds from wholesale, 
wanton slaughter. 
On Sept. 10, 1908, I noticed another multitude of Tree Swallows 
on the sandy beach. I could not make any estimate of the numbers, 
but when they settled down, the beach as far as I could readily see, 
appeared to be covered with black and white stones. In this 
flock, I noted one Cliff Swallow, the only bird of another species 
