It wasnt that subtle! But quite beautiful. It only happened the once, but what happened cannot be explained away. Basically, in the weeks after Nik went, on my daily walk I asked her if Guinness was with her.
The next day, same walk, 2 identical, tiny black and white birds kinda waited for me. Then, for about 10 or 15 minutes, instead of flying off as I approached, (as birds always do), they followed me. One at the heel of my left foot, the other a few feet away. I stop. They stop. I walk, they come with me. It dawned on me, so I spoke to the birds as they looked up at me. I asked Nikki if it is her and Guinness. The two birds tweeted at me, tweeted/looked at each other, tweeted at me again, and flew away.
Never happened before, nor since.