Bob, I have nothing to offer as to why this scored what it did. To me it's an absolutely delightful picture and very much in line with the challenge. Heh. Pun not really intended there, with the "in line" bit. Really adorable!
Although this is an adorable image I find it very snapshotish.. there are over exposed points and it seems it could benifit from a slight crop as well as levels adjustment.
Need to work on your exposure and contrast. Also the water has a lot of distracting grain that takes away from the cuteness of the photo. You may have too much water. More detail and closeness on this duck train may have created a stronger image.
Yep, baby ducks are always cute. It looks to me like you bumped up the yellow saturation too much and the water has a weird look to it. And the mom duck is lacking in detail.