The name "Sparrowtail" is inspired by the T'ai Chi pattern "Grasping the sparrow's tail". T'ai Chi movements have a variety of beautiful and poetic names (e.g. "white crane spreads wings", "embrace tiger, return to mountain", "repulse monkey").
The original names of T'ai Chi movements are in Chinese, and any English version loses some of the nuance of the name in translation. However, in the book "How To Grasp The Bird's Tail" (sadly now out of print, but you may be able to pick up a copy), Jane Schorre gives some fascinating insights into the possible meanings of the names of the various postures.
In particular, one possible interpretation of "grasping the sparrow's tail" refers to the concept of taking something apparently small and insignificant (such as a sparrow), then taking an apparently small and insignificant part of that (such as the tail), then examining that part, finding the meaning and purpose in it, and understanding it. As a T'ai Chi student's understanding develops, they learn to look at every posture and every movement in ever finer detail while maintaining an awareness of the bigger picture of the posture and it's position in the entire form.
In a similar way, successful software development depends on the developer's ability to understand the detail of any part of an application, while not losing sight of the whole application. The detail is where good software becomes great software, and I want to develop great software. It's all in the detail.