Chirp chirp, y’all! Ever wondered what birds mean when they’re singing their little birdy hearts out? This week, Molly and cohost Bessie explore the kinds of sounds birds can make, and how those sounds are used. Birdsong researcher Kristin Brunk breaks down some sweet tweet science, and we learn how human noise has affected our feathery friends. Plus, a groovy new Mystery Sound! This episode was sponsored by: Liquid I.V. (LiquidIV.com - Use code BRAINS at checkout to receive 20% off anything you order when you order.) Buy A Toyota (BuyAToyota.com - Explore Toyota SUVs.) Indeed (Indeed.com/BRAINS - To claim your ONE HUNDRED DOLLAR SPONSORED JOB CREDIT to upgrade your job post. Terms and conditions apply.) Bird sounds in this episode came from Xeno-Canto: Emily Brhel, XC760144. Accessible at www.xeno-canto.org/760144.  Manuel Grosselet, XC663795. Accessible at www.xeno-canto.org/663795.  Elias A. Ryberg, XC791170. Accessible at www.xeno-canto.org/791170. Sunny Tseng, XC749764. Accessible at www.xeno-canto.org/749764.  Sunny Tseng, XC753147. Accessible at www.xeno-canto.org/753147 Russ Wigh, XC573211. Accessible at www.xeno-canto.org/573211.  Russ Wigh, XC692169. Accessible at www.xeno-canto.org/692169. *****Do you have your Smarty Pass yet?? Get yours today for just $4/month (or $36/year) and get bonus episodes every month, and ad-free versions of every episode of Brains On, Smash Boom Best, Moment of Um, and Forever Ago. Visit www.smartypass.org to get your Smarty Pass today! See omnystudio.com/listener for privacy information.