Emmeline Grangerford is a maudlin artist who appears in Huckleberry Finn only through the work she has left behind after her death: ridiculous crayon drawings of grieving women and elegies to dead people. Although it was not intended to be, her work is quite comical.

Mark Twain used the character of Emmeline to satirize the Romanticism movement, which was known for producing works of art and literature that emphasized deep emotion as a kind of aesthetic experience; by encouraging the artist to freely express himself/herself, Romanticism left inspiration up to the ramblings of the unconscious mind, generating "something" from "nothing."

It might interest you to know that Twain actually based the character of Emmeline on Julia A. Moore, a terrible American poet who was renowned for writing overly sentimental, unintentionally hilarious work in the 1870s. 

In my opinion, Twain is satirizing romantic art and literature through the character of Emmeline Grangerford.  The Romantic movement was one that really emphasized strong emotions.

If you look at the kinds of art and poetry and stuff that Emmeline likes or that she creates herself, the stuff is full of really strong emotion.  It is all rather caricatured with all this stuff with "Alas" in the title.  It is obsessed with death, which is of course a very emotional thing.

So I think Twain is starizing Romanticism because he has Emmeline being so emotional over things like dead birds.