Erato means 'lovely', and she is the muse of erotic poetry and - fitting or not - mimikry. Thus, she is also the patron of parrots and crows (I just presume the latter also includes other birds of the crowlike family...;)
Erato is said to turn those who follow her into people who are loved and desired. All in all, a really useful muse here...
A little odd, Erato is shown in a dancing motion which had better fit her sister Terpsicore. Also, she holds a strange thing that is supposed to be a tamburin and not her 'trade mark' kithara, which we see in the hands of Terpsicore on the previous card. Maybe the original artist who first created this set of cards had mixed the two up.