Here's something you might not be aware ofhttp://www.pacificwildlife.org/info/online%20docs/fmbtalist.pdf
I read somewhere the cowbird eggs hatch faster than the host eggs and the hatchling pushes the other birds out of the nest. I've seen them in the yard begging food from their foster parents that are sometimes smaller than the baby.I wonder if they protect the cowbird as a starling population control measure?
The European starling is not protected. Easy to get confused on these lists so it's good to look up the individual species such as the ashy which is strangely enough native to Tanzania....
Cowbirds are protected under the migratory bird act regardless of what state people are in. In order to shoot them you must have a permit. If one has a permit, go for it. If not, then one is absolutely hunting them unlawfully. Hopefully no one is encouraging unlawful hunting on here. They are not an invasive species and there is no evidence that they endanger other nestlings.
There is lots of evidence that cowbirds hurt other species. Michigan DNR trapped and killed them in the thumb area for years because they drove the warbler population almost to extinction. Fact