Okay, I'm in a quandary.  When I adopted my neighbor's
abandoned, declawed cat, I assumed anyone who'd pay for a
declawing would certainly have had the animal neutered.
Now I'm not so sure.

My new little girl has begun behaving suspiciously like a
female cat in heat!  Last night she began yowling in that
characteristic manner.  The first time, I promptly went to
see what kind of trouble she'd gotten herself into.  She
seemed perfectly fine, the other cat was nowhere near, and
she promptly began weaving around my ankles and rolling
around on the floor showing her tummy. The howling continued
off-and on through the night (my poor neighbors!), but her
behaviour ohterwise showed no signs of distress - if
anything she was friendlier than she'd been so far.

Obviously, I plan to take her to the vet ASAP, but is there
any way to be sure whether a cat has been spayed?  (Short of
an ultra-sound, which would be rather exepensive.)  The
incisions nowadays are practically non-existent - I remember
Melisande's just looked like a pimple on her tummy - so
would even a vet be able to detect the scar?