Thanks for your wonderful comments. You inspire me - only 24 more blocks to go!!!
Here are the color changes I made to blocks M*N*O - not very interesting reading - grab your coffee or tea:
Mermaid: hair 838 to 938 & added a curl, flesh 407 to 950, tail 3052 to 3013 Fish: 3011 to 3012
Birds: 3857 to 3858, 838 to 839 3828 to 422, 420 to 680; Fledglings: 422 to 677, 3828 to 422 Nest: 869 to 3828, 838 to 839 BS: 422
Owl: upper chest 3828 to 422, lower body 3828; Leaves: bottom right & left red leaves next to trunk 3857 to 3858 Letter Box: leaves around letter 3012 to 3013, 3011 to 3012, 3362 to 3052, letter "O" 3857 to 3722 Small Owl: 3828 to 422, 838 to 839
I started in the center with the letter N because it was the largest of the blocks - 74 by 102, stitched it and then roped off all the blocks in that size. I really like the dark richness of the Flickr photo and don't want to lose that look. As for the colors, you've probably noticed I've gone a shade lighter, not really deviating in actual color (exception letter "O" which might get ripped out later - UGH!). I pulled out my DMC thread chart, found the original color and went from there. I was concerned that the first stitchers were finding that the alphabet letters were not showing up. The color world has its own language and I, unfortunately, have not learned it but I'm trying to keep all the letters the same value and still be visible. In some of the posted photos, I really like the white space left around the letters. If I had seen that first, I might have done the same and left that area unstitched. Hope this helps - Happy Stitching!