We decided to visit and camp at Colockum Pass based on it being recommended as a good place to bird. Our timing wasn't the greatest though - we visited in September, which is the beginning of hunting season. The place was crawling with hunters. We stayed close a closed off area that was to protect Roosevelt Elk. Hunters would literally drive around the closed off area waiting for an elk to wander off the reserve. Being such a high use hunting area, there were plenty of place to camp in areas that hunters created right off the road.
Other than the abundance of hunters, Colockum Pass was a beautiful place to stay. We had wild turkeys (protected and not hunted) wander through where we camped. And there were several Williamson's Sapsuckers in the area. The pass is a great place to stay and bird, though not highly recommended during hunting season.
Northern Flicker - "red-shafted" and "yellow-shafted"
Yellow-rumped Warbler "Audubon's"
Other Critter List
Directions: from Ellensburg (off I-90), take Colockum Road north.