456 
BIRDS OF NEW MEXICO 
to take a section of trunk, eight inches through and twelve inches long, 
“saw off from one end a piece two inches long; with brace and bit dig 
out an opening eight inches long and six inches wide. Then nail on 
the end sawed off. Make a suitable ventilation at top; bore entrance 
one inch in size near upper end of cavity” (in Trafton, 1910). 
The southward migration of the Northern Violet-green is said to 
be made in a leisurely manner, nearly a whole day often being spent 
circling over a pond of water or an alfalfa field, with occasional rests 
on telephone wires. 
TREE SWALLOW: Iridoprocne bicolor (Vicillot) 
Description. — Length: 5-6.2 inches, wing about 4.5-4.8, tail 2.3-2.5. Tail 
emarginate. Adult male: Upperparts steel-blue or steel-green; lores black, tail and 
wings blackish, slightly lustrous; underparts pure white. Adult female: Similar to 
male and sometimes not distinguishable, but usually 
duller in color. Young: Upperparts and tail dull grayish 
brown, wings somewhat glossed with greenish; underparts 
duller white . 
Range. —Breeds in Canadian, Transition, and Upper 
Austral Zones from northwestern Alaska, southern and 
western Mackenzie, Manitoba, and northern Quebec 
south to Virginia, Kansas, central-western Texas, Col¬ 
orado, and southern California; winters from central 
California, southern Texas, southern parts of Gulf States 
and North Carolina (casually New Jersey) south over 
greater part of Mexico to Guatemala and Cuba. 
State Records. —Breeding from Colorado northward, the Tree Swallow enters 
New Mexico in fall migration about the middle of August—August 13,1910, Carlsbad, 
3,100 feet (Dearborn), and August 14, 1903, Pecos Baldy, 11,600 feet (Bailey). 
Migration continues for about a month, and some late dates are: September 14, 1902, 
at Roswell (Gaut), and September 16, 1900, at Albuquerque (Birtwell). 
In the spring migration it enters the State about the middle of April. [It was 
seen in May, 1916, in the San Francisco Range (Ligon)J— W. W. Cooke. 
Nest. —In old woodpecker holes, a hollow tree, or bird! box; lined with grasses, 
leaves, and feathers. Eggs: Usually 4 or 5, pure white. 
Food. —Animal matter, 80.54 per cent, vegetable, 19.46 per cent. The vegetable 
food is made up of seeds and berries, as cornel, Virginia creeper, and smartweed. The 
insect food is composed of over 40 species of beetles, most of which are injurious, 
including small dung beetles, cotton boll weevils, clover weevils, engraver beetles 
(destructive to pine trees), flea beetles (destructive to cucumbers, potatoes, and other 
vegetables); and ants, wild bees, wasps, plant lice, leaf and tree hoppers, and chinch 
bugs (80, evidently from a swarm, in one stomach). Flies make up 40.54 per cent of 
the total food, the major part house flies, but also horseflies, robber flies, craneflies, 
and flower flies. “It consumes vast numbers of gnats, flying ants, beetles, mos¬ 
quitoes, and other flying insects" (Henshaw). 
General Habits. —The pure white underparts in conjunction with 
the uniform, glossy upperparts distinguish the Tree, or White-bellied, 
Swallow when flying low enough for its back to be seen, or when resting 
Fig. 76. Tree Swallow 
