I don't know of any studies to prove it is true, but I suspect that the US Midwest (in particular) has had a similar decline. Anecdotally I can say that there are certainly far fewer insects here than there were in the 60s and 70s when I was growing up, and also that there seem to be far fewer birds. I wonder if we'll stop dumping this stuff into the environment before it's too late. It would require a whole new way…
No there are not fewer birds. Ornithologists routinely census areas for species and counts. They notice when species decline in an area. They notice when new species arrive in an area. There have been zero reports of birds in general declining. EDIT: Here's a reference [1]. Note that it specifically calls out species in general decline: the Northern Bobwhite, American Kestrel, and the Loggerhead Shrike. [1] http://ww…
In fact, apart from two or three statements about one particular species I see not a single statement about the overall status. So I don't see how this article in particular supports your assertion of "No there are not fewer birds.", it does not say anything one way or the other. The only statements about bird numbers made in that article are about declines, but only about two or three selected species, for example with this sentence (quote from your linked article): "A disturbing finding from last year was the continued decline of the Northern Bobwhite".
So you may or may not be right, the one reference that you provide does not help me to come to a conclusion, except that I wonder why you chose it.