254 THE BIRDS 
many eves and young are destroyed by black snakes 
climbing the poles on top of which is attached the box 
or bird house erected by those desiring them around. 
While I have never personally seen a black snake in a 
martin box, I have seen them in other artificial nesting 
sites, such as Bluebird, House Wren, and Crested Fly- 
catcher, which I had put up on my farm. A long rainy 
spell checks the insect food supply materially, often result- 
ing in the loss of many young birds. The nests are 
generally placed in some box or house made for them, 
placed on top of a pole; many also building on ledges 
under the wide, overhanging roofs of houses. I do not 
know of a case in this section of their resorting to their 
old habit of building inside a hollow tree. Nests are com- 
posed of grasses, pine needles, straw, or weed stems, lined 
with a few green leaves and feathers. Eggs, white, four 
to five in number. Size, .95x.65. May 3rd to 25th finds 
a full set of eggs. They do not winter with us, arriving 
about April 4th. Occasionally they raise a second brood, 
June 15th. During the time the eggs are being incu- 
bated, the birds keep the nest supplied with green leaves, 
deposited around the rim, and continue to do so until the 
young are partly grown. Aside from their being beneficial 
as a poultry protector, the enormous amount of insect 
food taken while on the wing, classes them as one of our 
most beneficial birds. The colony remains around the 
box a short time after the young are able to fly, return- 
ing each night to roost in the box until they migrate south- 
ward, about August 6th. Those comine from further 
north pass through in flocks until September 10th. 
