Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. The babies are growing up. Since hatching in early April, Jackie and Shadow’s eaglets have sprouted new feathers, developed keen vision, and now, they’re practicing some vital grownup skills. Sandy and Luna can be seen engaged in lively wing-flapping sessions. While it might look a little awkward, the movement helps the chicks develop their pectoral muscles, an essential step in learning to fly. “It [also] helps them learn the ‘wingspan’ of their own bodies so they don’t hit the nest walls or their siblings,” Friends of Big Bear Valley (FOBVV), the non-profit group that maintains the eagles’ livestream, explains. But don’t expect them to fly away anytime soon. The chicks are only about six weeks old and fledging won’t happen until 10-14 weeks of age. Last year, Sunny and Gizmo each fledged around 13 weeks. 5-12-2026 Nest Bestie Bonding Viewers might also notice the pair stomping around their nest. Again, the eaglets aren’t exactly graceful, but this behavior is …