I have always been fascinated by crows, ravens and the rest of the Corvid family, so that is part of it.
The other influence comes from my favorite author, Charles de Lint. He has two recurring characters, Maida and Zia, who are known as the crow girls. They are always together spreading happiness, being boisterous
and generally making people feel good wherever they go, like the line "two for joy" in the old saying about counting crows or ravens, though I believe it originally referred to counting/seeing a certain number of magpies.
Regards,
Sarah