Sometimes authors use the “dead Dove do not eat” tag as roughly equivalent to the phrase “what it says on the tin”, and it literally can just mean “hey. Did you read the tags? That’s what’s in this fic. Make sure you read the tags”.
But the other dimension present, that it’s for heavier content as the OP said, I want to lean into that for a moment. Part of the reason that that scene and that phrase resonated for people, is because of the probable unpleasantness implied in finding a bag full of the carcass of a dove.
In a fair amount of fanfiction, there is a tendency to address heavy topics or tropes, and then kind of make them better? Like maybe there is some kind of abuse, but over the course of the fic the person heals from it, or the abuser gets punished… Or maybe there’s technically a major character death tag, but it’s only temporary death, and the character comes back, etc
Which makes sense, because fanfiction is largely a form of escapism, and for a lot of people that’s what they prefer. That bad guys get punished and All is resolved and everyone lives either happily ever after or happily for now. (Also historically, in many places media was only Allowed if it did that, and so even if other things may be allowed in more places now, many of us have grown up in cultures where most other media we consume operates that way. Think of the Bury Your Gays trope, which was required to portray queer folks within the boundaries of Hollywood’s Hayes Code, or the innumerable “very special episode"s of television, intending to teach the audience something)
But because there can be that unspoken expectation in fandom, that even when heavy stuff does come up, that the author will somehow make it better… Then even though heavy stuff was tagged for in a fic, if that stuff is NOT “made better” or explicitly condemned or whatever in the fic, sometimes readers can have a bad time or get mad or feel betrayed. The author tagged responsibly, but because of that unwritten expectation of “positive” resolution, (positive in quotes here, because not all readers have the same idea of what that looks like, which is part of the problem) readers can find themselves accidentally consuming content that they didn’t want to. Because experience has taught them that those tags are often not accurate to the “final” experience of a piece.
And so some readers may read things that are tagged in a way that Should indicate to them that it’s not actually stuff they want to read, but because they have these additional expectations, they ignore the warnings and read it anyway and then have a bad experience and get mad at an author (this is not what the OP did, to be clear, they seem to have, responsibly, had an unfortunate time and then gone. “Ah, my mistake” and moved on, knowing it was not the author’s fault).
And specifically to address situations like that, and avoid accidentally discomfiting readers or having people be hurt or angry in the comments, some authors use “dead dove: do not eat” (and there are sometimes fandom-specific variants of that tag that do a similar thing, like “hydra trash party” in the MCU), they use that tag as an extra warning beyond the regular content tags for heavier/darker/more intense or taboo subjects. specifically to say:
“THIS FIC CONTAINS ELEMENTS THAT SOME READERS MAY FIND UNDESIRABLE. What is in my tags IS in my fic, and I am not promising to somehow soften those things or make them better or undo them over the course of the fic. What it says in the tags is what is present. Do not come in expecting to find that those tags are not accurate. If you read those tags, and that is not a fic you want to be reading, with no caveats or conditions, then you should go elsewhere.”
Which is where the idea of “dead dove” as a complete Category of fic comes from– that “dead dove” fic is fic that deals with darker or heavier themes Specifically without any caveats or wrapping them up in nice bows. (I have told you there’s the corpse of a dove in this bag, and so if you open this bag and look inside, you will see the corpse of a dove) Maybe it’s content with unhappy endings. Maybe it’s content where “bad guys” get to do a lot of bad stuff… And no one rescues the hero. Maybe it’s heavy kink content that’s garunteed to squick some people. Maybe there is abuse, assault, or questionable/abscence of consent, and the fic is either from the abuser’s point of view, or otherwise the narrative does not go out of it’s way to “condemn” or “punish” the abusive character.
For dead dove content like that, the author is indicating that a different/specific set of social rules and expectations should apply. Instead of
“everyone mostly likes and wants happy endings and justice and things to be resolved neat and clean and fluffy, so I can assume that most people are operating that way and are taking the opportunity of fic to right wrongs and imagine a ‘better’ world” etc.
The contract proposed by a dead dove tag is
“We are both consenting adults responsible for our own experiences. We both understand that fiction is not reality, and specifically that any dark/heavy/fringe/taboo/unethical/dangerous elements present in this work do not in any way indicate what the author wants to happen or not in the real world, or approves of happening in the real world, and we are stating that now, so that we do not have to apologize or justify it again later. That is addressed here. I, the reader, am trusting the author to accurately and clearly warn for content, and the author is trusting me to know what content I will not like/should not be reading. By reading this tag, and the other tags, and clicking through, I the reader am consenting to read about what is portrayed in these tags, and if I find that something in this content upsets me, and it is something that was warned for in those tags, then I am taking responsibility for having made that choice, and will not be harassing the author about it afterwards.”
This kind of content and this kind of tagging is necessarily reliant on very clear and explicit communication. It both acknowledges that the content is not for everyone, but also that people who would like to engage with that content should be able to safely do so together.
In my opinion, it is an ideal evolution of fan spaces. In my opinion, it is absolutely wonderful that we have arrived here, that we now have tools and language that allows all of fandom to be together in one space and also be able to have exactly the kind of experience we each feel comfortable with and want to be having.
It DOES require education and conversation, however, which is why it’s wonderful that people like the original poster are taking the time to do that, and that people like those who asked questions of the original poster are taking the time to educate themselves. 💚