344 BULLETIN 17 9, UNITED STATES NATIONAL MUSEUM 



often peck the ground furiously, like barnyard cocks, but all fighting 

 is in the air. On a boundary this fighting often results in a curious 

 game of "tit for tat," as the male larks chase one another back and 

 forth. Every adventitious lark, wandering into established terri- 

 tories, is promptly evicted by the male. Such a bird will leave with- 

 out protest. So far as noted, the female is never the direct cause of 

 fighting; in fact fighting is most frequently noted when the female 

 is brooding and the male is no longer attending her. Only once was 

 a female noted driving out another lark, a male. She was defending 

 a recent nestling. 



The female has no courting maneuvers and was never observed to 

 sing. Only once was she seen to importune sexual attention and 

 then by a crouch and flutter similar to the actions of the English 

 sparrow. The male struts frequently before the female with wings 

 dropped, tail spread, and horns up. He will assume this attitude be- 

 fore another male at the territory boundary. 



Nesting. — The literature shows a surprisingly large range of 

 habitats in which the prairie horned lark has been known to nest. 

 These habitats, resulting for the most part from agricultural activity 

 or other human agencies, are those that most nearly result in barren 

 conditions. It does not matter that these barrens may be seasonal or 

 otherwise very temporary, if they are suitable for the initiation of 

 nesting. That bare ground is the determinant is shown by the fact 

 that variations of moisture, soil, elevations, and temperature will 

 all be tolerated in the selection of nest sites. The prairie horned 

 lark thus, it seems, does not differ greatly in the ecological condition 

 of breeding habitats from other horned lark subspecies. 



Some typical Chicago marsh in the Evanston region was drained 

 for a golf course. The course was later cut up into real-estate sub- 

 divisions; sewers were laid exposing a wide area of bare soil in the 

 streetways; and old sand hazards remained here and there. This 

 series of activities provided nesting sites for many larks. More than 

 a score of nests were located on this area (about 90 acres) in 1926. 

 A plot of vegetable gardens bordering this region on the west, where 

 larks had probably nested for some years, was also subdivided and 

 the vegetation subsequently neglected. Here several larks also 

 nested. 



The advent of vegetation in both areas and the demand of the 

 lark for bare ground forced a seasonal succession of horned-lark 

 breeding sites first from lot surface, to streetway, to sand hazard, to 

 vegetable garden, in the order that each was successively occupied 

 by verdure. 



At Ithaca, N. Y., one nest was located on the overturned sod of 

 a former hay meadow. Most of the observations there made, how- 



