I've kept my birdfeeders full, put out water for them, kept many thorny bushes I'd rather remove bc the songbirds love to nest in them and I am still seeing a decline. Not in the number of total birds, but each year the diversity goes down. Less songbirds, woodpeckers and hummingbirds, more cowbirds, more blackbirds. It's alarming.
I realize this is just my backyard, but it's wierd seeing a mass extinction just...play out. Right in front of me.