Current thinking is an abundance of hogs along the advancing frontier may have been one more of the nails in the coffin of the acorn- and mast-dependent passenger pigeon.
I'm going to need a link for that because I studied the case of the passenger pigeon pretty hard and I do not recall ever seeing hogs mentioned at all.
The passenger pigeon was killed simply because it couldn't nest. Once the northeast was covered in rails and telegraph lines, it was simply too easy for hundreds and even thousands of market hunters to descend on roosting sites and kill millions of birds in a week or two. And when the adult birds picked up and moved away to a new spot, rinse, wash, and repeat.
