PRAIRIE HORNED LARK 349 



distances of the intruder from the nest during this reaction vary from 

 25 to 100 yards or often farther, a greater distance, it will be noted, 

 than would disturb even a timid lark under other circumstances. 

 A reaction that in many ways is the reverse of this, but still a marked 

 exhibit of solicitude, is that called distress simulation. This con- 

 sists of a precipitate flushing and rapid flutter over the ground after 

 the nest has been approached closely. This reaction would be given 

 most frequently on very cold days, in the dusk of very early morn- 

 ing or evening, and when the bird was flushed very shortly after she 

 had returned to the nest. It is certainly more primitive than the 

 first reaction here described and is probably a culmination of the 

 more frequent distraction display that most birds present when their 

 nests are disturbed. Between concealment by abandonment and dis- 

 tress simulation there occurs a complete gradation, which, since the 

 reactions are exact opposites in expression, involves a curve that drops 

 from the first to the zero point and then rapidly ascends to the ex- 

 pression of the latter. Thus, between the two, lessened expressions 

 of either reaction would result, with a curious hiatus midway in 

 which the incubating bird would allow an intruder to approach 

 closely and then leave without an expression of either type of solici- 

 tude. Experimental flushing of an incubating bird from a blind 

 showed that the bird, in one case, would give distress simulation if 

 flushed in an interval that was less than two minutes from the time 

 of her return; but would give casual abandomnent if flushed after 

 an interval of five minutes. A female lark, shortly after being forced 

 from a nest, would express her agitation by aimless ground pecking, 

 and, to be sure, would eventually be driven by the incubation urge 

 to return to the nest even though an intruder might be much nearer 

 than he liad been when the nest was originally abandoned. This 

 complex of instincts involved both the urge to incubate and the urge 

 to protect. The instinct to protect, by wdiatever method, would all 

 be overshadowed in time by the instinct to incubate. 



Young. — With the exception of those nests of early April, in which 

 incubation began before the set was complete, all young hatched 

 within an hour or two of each other. The young are fed within an 

 hour or two following hatching. In most cases the male assisted 

 the female in feeding the young. In carefully observed cases he 

 visited the nest less often but brought greater burdens and fed more 

 young at a visit than did the female. A total number of observed 

 feedings during one day (April 30, 1926) was 108. The male fed 

 39 times and the female fed 69 times. 



Observations of the adults and dissection of a few nestlings showed 

 that some vegetable matter (weed seeds) is fed early in spring, but 

 that even in March most of the food is animaf matter. Later in the 



