266 BULLP]TIN 146, UNITED STATES NATIONAL MUSEUM 



does not involve the win^ coverts and very few scapulars, so that 

 j'^oimg birds can be recognized by these retained feathers. 



Adults have a partial prenuptial molt in March and April, involv- 

 ing the body plumage but not the wings and tail and not all the 

 scapulars and wing coverts. The black markings on the head are 

 acquired and the new feathers of the mantle are broadly tipped with 

 " pinkish buff." The complete postnuptial molt is accomplished in 

 July and August. The winter plumage is similar to the nuptial, 

 except that the black loral patch is lacking and the black crown patch 

 is replaced by dull brown. 



Food. — Feeding on the dry upland plains and prairies, the moun- 

 tain plover's food consists almost whollj^ if not entirely, of insects. 

 Grasshoppers seem to be its principal food, but many crickets, beetles, 

 and flies are eaten. It seems to be a wholly beneficial species. Grin- 

 nell, Bryant, and Storer (1918) quote Belding as saying "that he 

 often found this plover in recently sown grain fields, but was never 

 able to discover a single kernel of wheat in the stomachs of those he 

 shot." 



Behavior. — Coues (1874) writes: 



They were not difficult of approach, and I had no difficulty in securing as many 

 as I desired. On being disturbetl by too near approach, they lower the head, 

 run rapidly a few steps in a light, easy way, and then stop abruptly, drawing 

 themselves up to their full height and looking around with timid yet unsus- 

 picious glances. When forced to fly by persistent annoyance, they rise rapidly 

 with quick wing beats and then proceed with alternate sailing and flapping, 

 during the former action holding the wings decurved. They generally fly low 

 over the ground and soon realight, taking a few mincing steps as they touch the 

 ground ; they then either squat low, in hopes of hiding, or stand on tip-tms as it 

 were, for a better view of what alarmed them. 



Grinnell, Bryant, and Storer (1918) say: 



This plover is a flocking species found in bands of from fifteen to several hun 

 dred individuals. Often upon alighting after they have been in flight, the birds 

 will immediately run to some distance, so that it is not always possible to 

 follow them up easily as with other shore birds. The flocks fly low over the 

 ground and are difficult to see, except when they wheel. As they do this the 

 under surfaces of their wings show momentarily as silvery white flashes. 



Aiken and Warren (1914) say: 



The mountain plover differs greatly in habits and characteristics from it3 

 near relative the killdeer. It shows no preference for wet ground but on the 

 contrary frequents mesas or high rolling prairie land, often remote from water. 

 Their manner is quiet ; they have no wailing cry ; they run rapidly a short dis- 

 tance and stand silent and motionless with the head sunk low on the shoulders. 

 Their unsiwtted plumage blends with the color of the dry grass and parched 

 ground and makes them difficult to discover. But in August, when the young 

 birds shift for themselves, they gather in flocks and repair to the vicinity of 

 water holes and flooded fields. 



William G. Smith says in his notes : 



