No there is not, but one thing to consider is that if you have many similar objects you should put them in a list.
So the data frames data2015, data2016 should rather be something like birdsightings <- list("2015" = ..., "2016" = ...). Especially since you mention prefixes, that really sounds like you would rather want a list of data.frames.
You can add attributes or comments to data.frames in base R, but i never found that concept particularly useful (see help on ?attr and ?comment). I prefer to have my objects documented in the scripts that creates them.