As a case in point, witness this video, in which she dismisses Coleridge as a source for the expression "the birds and the bees" by virtue of being written in 1939, whereas the Cole Porter song, "Let's Do It," which has the line "Birds do it, bees do it," was written in 1928.
I have no idea where she got the 1939 date for Coleridge (some edition that she found?), but anyone with even the most cursory acquaintance with English literary history ought to know that Coleridge is early 19th century. The poem she references antedates the Porter song by over 100 years.
As far as I can tell, Marina is just presenting the Wikipedia page on this expression. These are the only two theories mentioned, and tellingly, if you check the page's history, the [correct] date of the Coleridge poem was only added after her video appeared on YouTube. [Before that, there was no date at all.]
[Update: the material in brackets was added to clarify my original intention. See also the comment from Marina herself below.]
This may seem like a minor point, but the whole focus of her presentation is on word history, so it's essential that she get her chronology right. More importantly, it would be nice if she did a little digging in some original sources instead of relying on others to do the heavy lifting. A quick search of Google Books turns up some interesting early uses of the phrase, which perhaps I'll write about a little later.
In any event, Marina is clearly aware of the Wikipedia criticism. See this video where she pokes fun at herself:
BTW, she hasn't made a dating error in this [second] video. Although her accent makes it unclear, she really does mean Gullible's Travels by Ring Lartner and not Gulliver's Travels.