Last year my family only had Ruby-Throats at the feeders,and this year we haven't seen a single one. Instead, we have at least three Black-Chinned, and now a Hummer has appeared that has us all totally perplexed. It is silver-grey all over, and seems larger, longer and 'sleeker' than any hummingbird I've seen. I work with a lady who lives 3 or 4 blocks away from me; she first saw these birds about a month ago and told me of it then. She now has at least four at her place. Any ideas as to what in the world they are? We have ruled out females of R-T's, B-C'd and Rufous. (I'm also setting up the camara stand to hopefully get a shot of these).