[Tiktaalik]

It's an apples and oranges sort of issue here.

I have no doubt that stray and feral housecats in the cities and suburbs are killing great numbers of common house sparrows, but the things that are driving down numbers of endangered birds in rural and remote areas (where feral cats are not a problem) is habitat loss and the decline in food sources (ie. berries and bugs).

[tga_d]

Feral cats are extremely common in rural areas (though not in remote areas). Ask anyone who's lived on a farm or ranch about "barn cats".

Regardless, "the single greatest source of anthropogenic mortality for US birds and mammals" sounds unambiguously not great, even if they're mostly not endangered.