Lark is getting some new and well-deserved attention as a post-Robin and Raven bird name. Although it was first recorded as a name in the 1830's, it has never appeared on the Social Security list.
'The Lark' was used as a nickname for Cosette in Les Miserables; Lark Voorhees was a star of Saved by the Bell, and Jennifer Connelly and Paul Bettany used Lark as the middle name of their daughter Agnes.
The expression "happy as a lark" gives this songbird name a cheery image, as well as a 'lark' being a synonym for a merry time..
Larkin is a pretty extension, as is Skylark, which is rich in cultural associations: there's the Percy Bysshe Shelley ode To a Skylark and the jazz classic Skylark written by Johnny Mercer and Hoagy Carmichael..