Why such a point of characters' birthdays?

[caspenzoe]

No: HPFGUIDX 110926

Sorry if this question has already been addressed, but, I can't help 
but wonder why, with the exception of Harry and Neville (whose 
birthdays are, or at least seem at this point to be, pivotal to her 
plot), JKR seems to feel that it's important to give us the 
birthdays of the characters in the series. 

What, for instance, is the point of telling us that today is Percy's 
birthday? August is not the seventh month in our current calendar or 
in any Latin or other calendar that I know of. Therefore, this 
information does not seem to be clue-related (clarifying or 
muddying) in any way. Likewise, why do we need to know that Fred's 
and George's birthdays fall on April 1st or that Ron's falls in 
March? Never, so far (please correct me if I'm wrong) has the 
celebration of anyone's birthday other than Harry's and Dudley's - 
oh and NHNick's - ever even been mentioned in canon.

Is JKR trying to suggest some character traits based upon 
astrological significance in revealing the birthdays? This hartdly 
seems likely given that, in canon at least, she doesn't seem to 
espouse any belief in such significance; quite the opposite, she 
pointedly excoriates (through her characters) Trelawney's beliefs in 
things astrological. On the other hand, given her four Hogwarts 
houses, suspiciously correspondent to the four astrological elements 
(fire [Gryffindor, lion, red, Leos Harry & Neville, Aries Fred & 
George, Leo Percy(?)], earth [Hufflepuff, yellow, Virgo Hermione & 
Percy (?)], air [Ravenclaw, eagle, blue], and water [Slytherin, 
snake, green, Pisces Ron]), and her apparent birthday obsession, 
what on earth is she trying to communicate? Do these so-
called "elements" have some alternative alchemical siginifcance I'm 
unaware of?

Thoughts anyone?

Caspen