KILBUCK AND AHKLUN MOUNTAIN BIRDS 145 



Table 17. Continued. 



Dwarf shrub mat 



Low, medium, and tall shrub thicket 



Common name Status 



Common name Status 





Common redpoll B 





Hoary redpoll B 



birds of wetlands, typical tundra habitats, thicket and forest habitats, or 

 coastal cliffs. On our study area, most of the widespread but uncommon- 

 to-very-rare species used wetlands or rivers, dwarf shrub mat other 

 alpine habitats, or thickets or open forests. 



Thirty-one species were normally associated with thicket and forest 

 habitats in the Kilbuck Mountains, of which only 18 (58%) were found 

 in the Ahklun Mountains. This reduction with distance into the taiga- 

 tundra ecotone was predictable but might have been exaggerated by 

 limited fieldwork in the woodlands of the Ahklun Mountains. However, 

 of the 51 common species of the interior Alaska-Tanana valley taiga 

 (Spindler and Kessel 1980), 46 (90%) nested or probably nested in the 

 Kilbuck Mountains, whereas only 21 (4l%) nested in the Ahklun Moun- 

 tains. These taiga species were 53% of all breeding or probably breeding 

 species in the Kilbuck Mountains, and 28% of all breeding or probably 

 breeding species in the Ahklun Mountains. 



Twenty-eight species nested both at Napaskiak and within our study 

 area. Of those 28 species, Williamson (1957) suggested that 6 species 

 (21%) penetrated the taiga-tundra ecotone in the lower Kuskokwim 

 River area to only a limited extent, 50% penetrated the ecotone some- 

 what further, and 29% occurred throughout the ecotone. Our data for 

 the same 28 species agree with Williamson (1957), although we found 

 some species penetrating the ecotone farther (e.g., common redpoll). 

 A complication in our area was that some species (e.g., Bonaparte's gull) 

 occurred in a separate taiga-tundra ecotone at the Togiak River (which 

 extended west from the Wood River-Tikchik River area woodlands) as 

 well as in the main taiga-tundra ecotone extending south and east from 

 the Kuskokwim River area. Still other species were rare or absent in our 

 upland area, but Williamson (1957) found them common in the taiga- 

 tundra ecotone in the Kuskokwim River lowlands (e.g., black scoter). 



Twenty-two species of the thickets and forests in our area were not 

 recorded in the same ecotone by Williamson (1957), and some of these 

 were sufficiently widespread to be characteristic of our taiga-tundra 

 ecotones (e.g., golden eagle, arctic warbler). Most of these 22 species 

 were restricted to the extreme interior of the ecotone or fluctuated 



