Cool observation, Brian. I’d suggest that this bird probably was an early fall (southbound) migrant. In other parts of the interior west, including much further south (Arizona and New Mexico), southbound migrant rufous (typically beginning with adult males) routinely arrive around the final week of June. The first southbound shorebirds (usually beginning with Phalaropes, Tringa sandpipers, and peeps) should also begin to appear any day. “Fall” migration begins in late June after about 10 slow days in the middle of the month.