144 Trans. Acad. Sci. of St. Louis 
parents, especially the female, with her “abandonment conceal- 
ment” are calculated to take advantage of the protective color 
of nest and young at all ages. 
12. Nest leaving. Young leave the nest usually by following 
a parent that has brought food. One case was noted wherein 
the female enticed a belated nestling from the nest with a 
food morsel. The young fly in about five days after leaving 
the nest. They hop for some days after nest leaving whereas 
the adults walk. This hopping may be anatomical or an 
atavism. 
V. Molt. 
Dwight (1890) showed that juveniles and adults have a com- 
plete molt in late summer. Breeding plumage is acquired by 
the wearing off in late winter of the brown tips that obscure 
the areas of blac 
VI. Eeology of the Nesting Site of the Prairie Horned Lark 
in Relation to Other Breeding Birds at Evanston, III. 
Throughout March, April and most of May the Prairie 
Horned Lark is the only breeding bird in the open field. The 
growth of verdure at Evanston, Ill., presented such a range of 
conditions that nine species and about 74 pairs of birds were 
occupying it in June, however. Though most of the Larks had 
been driven from it by this change of conditions, a few re- 
mained in the barer areas. A category of these breeding birds, 
listing their nest sites in descending order from the heaviest 
vegetation to the scantiest, gave the following: Dicksissel, Bobo- 
link, Savannah Sparrow, Meadowlark, Vesper Sparrow, Prairie 
Horned Lark. The Vesper Sparrow, as well as the Prairie 
Horned Lark, suffered a seasonal modification of nest site and 
was obliged to move for later broods, about two weeks of plant 
growth behind the Lark. Comparisons of many other habits 
are also noted. 
VII. Non-breeding Birds That Fed on or Above the Territory 
Occupied by the Prairie Horned Lark at Evanston, Ill. 
Twenty-eight non-breeding species of birds were noted feeding 
on or above the Evanston territory. Of these the most interesting 
were the Lapland Longspurs that occupied it with Larks i 
