I agree with Bob Armstrong that dogs should be "controlled" when walking on the Mendenhall/airport dike trail (and other areas as well). However, I do not think keeping dogs leashed is necessarily the answer. It certainly may be for some dogs, particularly at sensitive times of the year.
However, with a little common sense and courtesy, dog walkers should be able to continue to use the dike trail without harming the wildlife. Many of us who walk with our dogs are very aware of the importance of that area to wildlife, and in fact enjoy the dike trail specifically because of the abundance of birds and other wildlife, especially in the spring.
Just yesterday I walked the dike trail with one of my dogs, off leash for the majority of the time. In one area, there were hundreds of geese and ducks feeding and resting in the ponds between the trail and the airport. I thought this might prove a little too tempting for my dog, so when we went past that area, I called her to me and clipped on her leash, which I always carry with me. My dog stayed on the trail the entire time we walked, even when she was not leashed, and not a single feather was disturbed.
There was a woman walking behind me with a lab. She kept her dog's attention as they walked by tossing a stick along the trail for her dog to fetch. The lab stuck to the trail, retrieving its stick, and ignoring the birds. The woman and I commented to each other how beautiful the geese and ducks were.
This is the kind of common sense the Grateful Dogs of Juneau is advocating - being aware of wildlife and conscious of your dog's limits, and not bothering other users. Educating users with dogs about the importance of maintaining adequate control is a better way to solve this problem than instituting unenforceable rules that diminish the experience for many users.
Grateful Dogs of Juneau