Since I've been banned from commenting on WUWT here is my response to
All bird deaths obviously should be avoided but consider your personal footprint in these deaths:
Berthold referred to a study published earlier this year in Nature Communications which found that free-ranging domestic cats kill 1.4–3.7 billion birds (as well as 6.9–20.7 billion mammals) annually: that works out to 40 birds killed per cat every year. Many of those birds represented the end of their species: as many as 33 species of birds are thought to have been eradicated by cats. However, it’s worth noting that stray cats, as opposed to pets, cause most of the damage.
From Sibley Guides
Figures are believed to be US only
Here's one that didn't make it. Window on our house facing west.
Communication towers – estimates of bird kills are
impossible to make because of the lack of data, but totals could easily
be over 5 million birds/year, and possibly as many as 50 million.
Electrocutions kill tens of thousands of birds per
year. This occurs mainly when large birds such as raptors make contact
between a live electrical wire and a ground such as a pole. The
relatively small number of birds affected belies the significance of
this threat, since species such as Golden Eagle are more susceptible.
Cars may kill 60 million birds per year.
Wind turbines may kill 33,000 birds per year, and, as
in the case of electrocutions, these birds tend to be large and scarce
Pesticides may kill 72 million birds per year or possibly many more.
Oil spills kill hundreds of thousands of birds a year or more
Oil and wastewater pits may kill up to 2 million birds per year.
Lead poisoning – kills unknown numbers of birds each
year, but Bellrose (many years ago) estimated that about 4% of the
waterfowl population dies annually due to lead poisoning, and the
California Condor recovery team stated that lead poisoning was the
primary cause of the condor population decline over the last 50 years
Hunting - as
a point of reference the carefully-managed annual waterfowl hunt kills
about 15 million birds a year in North America. This, of course, is
balanced by extensive and well-funded management and conservation
efforts so hunting is not a threat to the population of any North
Domestic and Feral Cats – may kill 500 million birds per year or more.
From a famous twitcher