Thanks Brant ..... those are really good Downy pics.
There are 3 main ways to differentiate the Downy vs Hairy WP
1. Size: Downy is about the size of a sparrow (maybe 4-6 inches tall). Hairy is the size of a Robin (8-10 inches tall)
2. Bill: Downy has a short bill about 1/3 to 1/2 the head size. Hairy has a much larger bill more than 1/2 head size
3. Tail feathers: Downy has white outer tail feathers with spots of black and/or gray. Hairy has all white outer tail feathers with no spots
Looking forward to your images of the Hairy WP. They are frequent visitors to my set up but they are usually very nervous and easily spooked so it isn't often that I can image them in a good pose. One thing that helps is they will often stay out in the woods a bit and call several times before they come in so I can pre-focus on the perch that I expect them to use. That way very little camera movement is needed to get a few frames before they jump to the feeder or bolt away.