I have gotten a couple of e-mails from folks who say they stopped seeing their backyard hummingbirds in early July or have not seen any.

One birder writes: "Where are all the hummingbirds?  This is the first year in many that I have yet to see even one hummingbird. My feeders have been out and changed regularly. I miss the show. Do you have any idea what's up??"

I just saw a hummingbird zipping around our cardinal flowers the other day, but I have not put up hummingbird feeders this year so I do not have a good grasp of the situation.

Has anyone noticed any changes in hummingbird populations and, if so, why?