204 
BIRDS OF NEW MEXICO 
section but on November 29 two were discovered on one of the Costilla peaks, 
farther north (Ligon).]—W. W. Cooke. 
Nest. —On ground frequently in the open, a depression in the grass or scantily 
made of grasses and a few feathers. Eggs: 8 to 15, dull creamy to pale reddish, 
generally lightly but sometimes more heavily marked with brown. 
Map 4. Southern White-tailed Ptarmigan 
Shaded areas show former and present range 
Food. In winter, largely willow buds and leaves; at other times, so far as known, 
beetles, grasshoppers and other insects, seeds, flowers (heather, blueberry, etc.), 
leaves, catkins, and the buds and leaves of dwarf birches, pines, and firs. The 
crop of one New Mexico specimen was filled mainly with leaves of the dwarf willow, 
and fruiting spikes of Polygonum viviparum , with one flower of Geum rossii, while 
the gizzard held mainly Polygonum seeds, a few other small seeds, a few small 
grasshoppers, and other small insects. 
