112 Trans. Acad. Sci. of St. Louis 
no time does the young Lark have an audible food call (such as 
the continual clamor of young Cowbirds or young Baltimore 
Orioles, for instance), except when the parents are directly at 
the nest. Even then it is not audible more than a few feet away. 
In all plumages the young are remarkably concealed whether 
it be their clay-colored down or their mottled juvenile plumage, 
which is such a remarkable ‘‘picture pattern’’ of the lights and 
shadows about a ground nest (Plate X XXIII). 
The actions of the parents, especially abandonment conceal- 
ment and a stern reluctance to approach a nest in which there 
are young, are well calculated to protect ground nests. 
Nest leaving—The age of the young at nest-leaving de- 
pends upon the manner and amount of food they have received. 
The average is between the tenth and eleventh day. Some go 
on the ninth, one set remained until the fourteenth. They 0, 
usually, merely by following a parent who has just brought them 
ood. In one case I observed the female entice a belated young- 
ster from the nest by coming up with food and retreating until 
his hunger forced him out. 
Just prior to nest leaving, as has been noted, the young 
acquire a ‘‘crouch-concealment’’ habit that stands them in good 
stead once they are away from the nest. This crouch or ‘‘freeze”’ 
is maintained at all times, when the parents are not near, up t0 
five or six days after nest-leaving (Plate XXXIV). If they are 
disturbed when in this ‘‘crouch-concealment’’ they will not 
return to it unless left for a moment with one of the parents. 
This habit, plus their peculiar plumage, makes the Lark similar 
to the precocial young of a gallinaceous bird as Chapman (1918) 
has noted. Indeed the Larks are semiprecocial in many Te 
spects, not the least of which is the habit of leaving the nest 
several days before they can fly. 
any writers have noted that the young Larks leave the nest 
before they can fly and Forbush (1911) sets this time at a week. 
This is a little too long however. By banding the young I was 
able to get some definite material on this. Thus one young Was 
caught, able to make flights of about one hundred yards, at 
fifteen days of age. This one had been out of the nest just five 
days. 
The parents must find their quiet youngsters, in their crouch- 
concealment, by some method other than sound. To do 
