Red Wing Black Birds invasive?

[AbAngler]

Can't find the info.... A buddy was telling us over the weekend that Redwing Blackbirds are invasive and that he shoots them. I was surprised and kind of like them but the guy isn't a BSer, so I believe him but can't find anything to confirm....

Are they invasive? Perhaps the more google inclined members could point me to an actual link?

Thanks in advance!