chaoticneutral said "North America has lost three billion birds since the 70's due to loss of habitat, pollution and, well, humans. it's not that surprising that you're noticing less of them. "
If that is the case then please explain to me why we observe greater numbers and varieties of birds ( including migratory birds), mammals , insects, wild plants and flowers establishing and thriving on and near our mixed farm every year.
The biggest habitat loss that we never discuss or challenge is caused by development of land to expand towns and cities.
That said I live in a smaller town and we observe a huge wild bird variety at our sunflower seed , Nyger seed and suet feeders.