Why is my unspayed cat chirping, meowing, and arching her back?

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Finney. Sounds like she is in heat. These are typical in heat behaviors and cats respond to the increased daylight that starts in late December and January. Female cats will go into heat and cycle out of heat a lot during this time unless they are spayed. Each heat generally lasts several days - it can be as short as 1 day or as long as 7 days. If the cat is not mated during estrus, she will "go out of heat" for a short period of time, usually 1-2 weeks. Thus, the average complete estrus cycle of a cat is 1-3 weeks. Cats are induced ovulators meaning that they don't ovulate an egg from their ovary unless they are bred. This is why Finney will continue to cycle in and out of heat as described above. I would advise getting her spayed as soon as you can unless you plan on breeding her someday. Good luck with Finney.