Bill - Somewhat confusingly, Cornell has two different Merlin offerings.
One is the original Merlin Bird ID app that is available both online and
for mobile, as you mention. With this program, you answer questions
about where and when you saw the bird, the color, shape and size of the
bird, habitat, etc. and it guesses what your bird is based on your answers.

Their other Merlin program is called the Merlin Photo ID. It is at the
link I gave in my earlier post:
http://merlin.allaboutbirds.org/photo-id-help/

At this link, you upload your photo, draw a tight box around the bird,
click first on the tip of the bill, click second on the eye, and click
third on the tip of the tail. Then click on the submit button, and the
Merlin program will guess what your bird is.

It often is right, but also a fair number of times wrong. The better
your photo, the better Merlin performs, which is not surprising. It also
apparently does better when the bird is in a "typical pose." The
Cornell researchers are trying to improve Merlin Photo ID's performance,
and I gather that the more photos it sees, the better it becomes.

One of the shortcomings of the program is that it can ID only the
commonest North American species -- 400 in its database. So if your bird
falls outside of that group, you're out of luck. But I do not mean to
complain -- it is a miracle that Cornell has gotten as far as it has
with this program.

As I mentioned earlier, just for fun, I ran one of your photos through
Merlin Photo ID, and it identified it as Canyon Towhee.

Jane