red eared slider pond turtle spring behavior

Question
This red-eared slider pond turtle lives in a pool in my back yard in southern California.  Every Spring she gets restless and starts trying to get off our property - looking for a mate I think - and roams all over, including coming into the house. Her favorite spot is in front of the mirrored sliding closet doors.  It seems she thinks this is another turtle.  Have you ever heard of a turtle recognizing "a turtle" in a mirror  Isn't mirror recognition supposed to be a high form of intelligence?  
  Also, how long can this species of turtle live?  I have her for about twenty years.  I got her when I lived in New York and she was about the size of a quarter.  Sheis quite large now, almost the size of a dinner plate and heavy.  Her shell is in excellent condition and she sheds it at least once a year. She has had the run of my backyard and pool (pool is salt conditioned, not chlorine) for the past ten years.  I feed her (in the pool) fresh meat and fish -- she won't eat turtle pellets or fruits or vegetables. The pool has a sloping entrance so she climbs out a few times a day to sun herself and also spends time in a favorite hidden spot under a bush.I decided it's a female because the bottom of her shell is flat (not concave) and her back legs are very large and strong.   She only comes into the house in the Spring.  Rest of the year she does not roam and seems quite content.  She likes to swim over to us when we go in the pool and sit on on a shoulder.  Anything you can tell me about Myrtle (that's her name) would be vastly appreciated. 100_0065.JPG

Answer
Hi Rosalie,

Sorry, but your picture didn't show up.  Congratulations on having Myrtle for 20 years!  You must be doing something right to have her in good shape for that long.  RES can live about 40 years, which isn't that long compared to some tortoises, but it's a good, long time.  Not all turtles/tortoises have the shell differences (convex/flat) you were talking about, including RES, but Myrtle is definitely a female, based on her size--males are considerably smaller.  

Turtles actually have pretty good eyesight, and she may very well recognize her reflection as another turtle.  The spring restlessness may be due to interest in mating, or simply because it's spring--turtles are programmed to be most active in spring and will roam more, eat more, etc.  As the summer progresses, they will gradually slow down until they go into hibernation in fall.  

Adult RES are generally primarily herbivores, while hatchlings and juveniles are more carnivorous.  They shouldn't be given fruit or vegetables, though.  Since she seems to be healthy, if she doesn't want greens don't worry about it too much, but you can try giving her leafy greens such as turnip, dandelion, collards, kale, etc.

Good luck with her, and thank you for providing a good home for her.  There's so many RES dumped in rescues every year that it's nice to hear about one having a good life.  :)