See the most recent WWF page on birds and climate change here. WWF contends that "Birds suffer from climate change effects in every part of the globe. Scientists have found declines of up to 90 per cent in some bird populations, as well as total and unprecedented reproductive failure in others."
Then, here is the equivalent page from BirdLife International.
The National Audubon Society has information of its own at this page.
Great Britain's RSBP has its information posted here.
More at: this link
"Mistle thrushes are disappearing from UK gardens says the RSPB. The
RSPB’s annual Big Garden Birdwatch survey – back this weekend - shows
that mistle thrushes are now seen in fewer than half the number of
gardens they were seen in ten years ago."