Good morning Napper
The birds that you are missing like the Red-winged Blackbirds, Common Grackles, Cedar Waxwings, and Robins are not gone yet. Most of them disappear from the breeding areas by 1st of August or so and end up in sometimes huge flocks in fields north of the city or marshes. In October if you are in the right place like High Parks Hawk Hll or base of Leslie St. Spit in the am you may see many thousands of these birds (including Bluebirds) as they start their migration and if you go to Long Point in late October through November you could encounter up to 100,000 Blackbirds including Rusty, Red-winged, Grackles, and Cowbirds in the and around the marshes.
As far as the Swallows go there are already hundreds of them at the Leslie St. Spit as they prepare for their migration and they start to gather along the Lake Erie North Shore in their 10's of thousands now before they migrate at the end of the month and into September and Waxwings also gather in flocks prior to migration even though some stay the winter.
You have noticed the Goldfinches singing,. This is their nesting time. The Leslie St. Spit yesterday had 30+ Goldfinches there, singing, displaying and gathering nesting material.
Hope this clears up the missing birds mystery.
Norm