1921 BIRDS OF MONTANA 17 



which are less than a hundred feet across. They are only found in the moun- 

 tainous parts of the state, and are more abundant in the northwestern part of it, 

 particularly in the Glacier Park, where there are said to he at least two hundred 

 and fifty. As in the case of prairie lakes, the l)ird life of these lakes is very vari- 

 able. One species, the Spotted Sandpiper, is characteristic of tlieir shores, and 

 may be practically always found about them. Other species are local, such as 

 ducks (particularly tree nesting species, like the mergansers, golden-eyes and 

 Buffle-head), the Canada Goose, Osprey, Kingfisher and Tree Swallow. 



Rivers (see fig. 3) flow mainly through the prairie region and the moun- 

 tain valleys. They are much varied in character, and might perhaps be divided 

 into several stream-border associations, according to whether their banks were 

 bordered by grass-meadows, cottonwood groves, or rocky cliffs. The birds breed- 



Fig. 3. View ox the Teton River, ivEAit Button, Teton County, Montan.\. 



GRASS-tOVERED BENCH-LANDS IN THE FOREGROUND AND IN THE DISTANCE, AND 

 COTTONWOOD GROVES BORDERING THE RIVER. TRANSITION ZONE. PHOTO BY A. D. 



Dubois. 



ing along these rivers vary, and, as in the case of mountain lakes, the Spotted 

 Sandpiper is the only species that is entirely characteristic. Other species found 

 more or less locally along rivers are the Great Blue Heron, Killdeer, Kingfisher, 

 Kingbird, and Bank Swallow. Where steep cliffs border the sides of rivers, 

 some species nest in the cliffs, but since their presence is due to the rocks rather 

 than the water, they should be considered as belonging to a rock association. 



Mountain streams (see fig. 4) are somewhat similar to rivers, except that 

 their current is swifter and that they contain frequent waterfalls and rapids. In 

 some places well within the mountains the streams often take on the quieter 

 character of rivers, and in such cases the one characteristic bird of river borders 



