Serious Question. What has happened to the birds?

I'm from Canada - Prairies - near the Mb.and Sk. border (rural area). I first noticed the absence of many humming birds. I used to fill 3, 4 cup feeders twice a week. This year I've only needed one and I often had to change the contents because it was too old. Over the past few weeks I've noticed there are no robins, gold finch, grosbeaks, and even the sparrows are gone, all of which were here in early spring. My neighbor was down today and I asked her if she noticed something strange on my yard. Without hesitation she said - "there are no birds." They are not laying around dead either. They simply disappeared. I even checked our old barn for barn swallows. Usually it's quite noisy with all their chattering. NOTHING!! Total silence. Has anyone else noticed this?