Next, we can begin to ask (and answer) important scientific questions, like what weather conditions might explain in-flight behaviors like changes in flying altitude? And how much do birds rely on favorable winds during migration? (Think about how moving in the same direction as the wind makes you go faster — the same is true for birds!). With climate change, these questions have new urgency.
Climate change is already causing spring to arrive earlier. It’s also expected to alter atmospheric conditions, like the strength of winds. So, what might that mean for birds? As birds travel earlier or faster to keep up with the advancing spring, will they have the same wind support they evolved with to complete their journeys? If not, will they use more energy? And how might that affect them once they reach their destination?
We can also think about ways to conserve aerial habitat for migratory birds, just like we protect their habitat on land. Where should we create safe sky spaces, free of drones and planes? How can we prevent light, chemical and sound pollution in areas where birds travel? Where should we avoid building wind turbines and radio towers?
Answering these big questions will take more time and data, but the long-billed curlew’s fall 2020 migration is already brimming with interesting results. The curlews typically started long flights in the evenings and often continued flying into the daylight hours. Their entire trips totaled around 45 hours, with each long leg lasting 10 to 25 hours. One female curlew, called Tapes, flew the entire route from Montana to Central Mexico in one 44-hour flight, covering 1,641 miles (2,641 kilometers).
During the first part of an evening flight at the start of migration, a female curlew called Carmen flew at high altitudes. She returned to high altitudes again during the daylight hours, as she continued her journey south. Carmen also had the quickest ground speeds when she flew at higher altitudes, suggesting she may have found favorable tailwinds there.