Here is the best photo to date, taken by Kent Mortensen this morning with computer lightening by Terry Gray. It is my best evidence of it being a Rusty, showing the face pattern and rusty wing feather edges.
Just a couple notes about the significance of a Rusty Blackbird showing up in Idaho...
1. The Rusty Blackbird is listed as a Review species for the Idaho Bird Records Committee.
2. 20 sightings have been recorded in Idaho since 1952, but only five are records accepted by the committee. (IdahoBirds.net)
3. This is the first Rusty reported in the Treasure Valley since the 1996 Nampa Christmas Bird Count.
4. Populations of Rusty BB's have plummeted by 88-98% in North America. (eBird)
5. Rusty Blackbird will summer in Alaska and northern Canada and winter in the central midwest, east coast, and southern United States - a long way from Idaho.
6. 11 of the reported sightings in Idaho were in December or January.