Does color of bird blind matter?

I shoot from the house window which is about 10-12' from the feeders & perches. Currently I am using 2 old towels (1 red, 1 blue) which is draped across the window opening to hide myself. This technique works for the most part but I wonder if the birds would feel more relaxed and take less notice if I used camouflage fabric instead of the brighter colored towels.

Thanks for any feedback.

I used a blue tarp when I started and now use a camo tent style hide when I need to get a little closer...I see no difference. The biggest thing I feel is masking quick movement.

As long as your movement is concealed I don't see the need for camo in your situation. When trying to blend with your surroundings in the field camo would be wise, as well as setting up near or among vertical objects like trees and other foliage. At home the birds are comfortable/familiar with your blind so their only concern is your motion.

I use an old white sheet in my conservatory door when shooting from a similar distance, doesn't seem to bother them.

It depends on where you are.

If in an urban environment, the birds are use to our odd colors. (houses cars, pavement etc dominate the landscape)
In more rural settings, white can be a real problem, as can bright unnatural colors.

It's just got to do with what the birds are used to having around.

Mostly, just hiding you and your movements is what is needed.
I don't think Camouflage patterns are required much at all, but earthy tones over pastels and brights can certainly help.

Camo is as much about breaking up out lines as it is about colour. I like to use it if I plan to sit quietly in the woods letting things come to me. At home I use a sheet of plywood (fairly light coloured) fitted into the window. It has a hole cut in the centre covered is covered by a black rubber flap. It works very well as a blind.