Here are some studies about bird mortality in the US.
Bird-Communication Towers - 6.8 million birds/year.
"The resulting estimate of mortality at towers is 6.8 million birds per year in the United States and Canada."
Bird-Vehicle - 89 million birds/year
"We estimated that between 89 and 340 million birds die annually from vehicle collisions on U.S. roads."
Bird-Building - 599 million birds/year
"We estimate that between 365 and 988 million birds...are killed annually by building collisions in the U.S., with roughly 56% of mortality at low-rises, 44% at residences, and,1% at high-rises."
Bird-Wind Turbine - 234,000 birds/year
"We estimate that between 140,000 and 328,000 (mean = 234,000) birds are killed annually by collisions with monopole turbines in the contiguous U.S."
Bird-Power Line - 26 million birds/year
They "estimate that between 12 and 64 million birds are killed each year at U.S. power lines."
Bird-Aircraft - 13,668 in US in 2014
And, lastly, I must throw cats into the mix:
Bird-Cat - 2.4 billion birds/year
"We estimate that free-ranging domestic cats kill 1.3–4.0 billion birds and 6.3–22.3 billion mammals annually."
This study has been contested. Professor of Anthropology Barbara King complained about "demonizing cats with shaky statistics."