On a migration stopover on Roberts Bank, B.C., scientists discovered western sandpipers prefer diatom biofilms over other larger food sources. The diatoms are rich in essential fatty acids fueling their journey. Expansion of a nearby shipping port may disrupt the unique balance of the delta ecosystem—changing water flow, salinity and the diatom species mix and altering this vital food source not only for the sandpipers but also for the rest of the estuarine food web.