Need Some Insight (1 Viewer)

I'm not a bird person. Couldn't tell you the difference between a wren and an owl, so this might be a challenge for you. In fact, I only joined this site to see if anyone out there could help me with what I saw.

I live in central Illinois (United States). The other day I was sitting on my deck and I noticed some birds in a neighbor's tree. One was a small black bird with a yellow beak. The others were smaller, grayish in color. The black bird was sitting on a branch, clutching one of the smaller grayish birds, which was hanging upside down beneath the branch. The black bird was pecking at the smaller one, which I initially thought was dead. (The other gray birds on nearby branches didn't seem too concerned with what I thought was some sort of intra-species murder in their midst.) Anyway, after a few more pecks, I was surprised to see the dangling bird flap its wings and take off. The larger black bird didn't pursue it. Just sort of sat there nonchalantly like, eh, whatever. Instead of being frightened by the black bird, the smaller birds kept hopping closer to the larger, black bird.

So then I thought that maybe the black bird was some sort of cleaning service for the smaller ones ... picking off parasites or something. I waited for something else to happen, but the small black bird flew away after a moment. The smaller grays didn't pursue.

Is my cleaning theory even remotely possible? If not, any idea what I might have been seeing? Again, I have no idea what type of birds they were.

I'm very curious about this behavior. To be honest, I'm starting to get a bit obsessive over this, so any insight you can give me would be appreciated. Thanks.

I'm not aware of any bird species that provide "cleaning services" by picking parasites off other species, as you see in some fish. More likely some sort of dispute over food or nesting space.

For identification, I'll take a stab and suggest that the black bird with a yellow bill was a European Starling. They'll be prospecting for nest holes this time of year and can be aggressive toward other species. Without more information, it's hard to say what the other species you observed were.