One morning in January, I found myself 30 feet (9 meters) up a tall metal pole, carrying 66 pounds (35 kilograms) of aluminum antennas and thick weatherproofed cabling. From this vantage point, I could clearly see the entire Punta Banda Estuary in northwestern Mexico. As I looked through my binoculars, I observed the estuary’s sandy bar and extensive mudflats packed with thousands of migratory shorebirds frenetically pecking the mud for food.
In winter, more than 1 million shorebirds that breed in the Arctic will visit and move throughout the coastline of northwest Mexico. It’s possible they are tracking rare superabundant seasonal resources like fish spawning events. Or maybe they are scouting for sites with better habitat to spend their nonbreeding season. The truth is, researchers don’t actually know. It has been incredibly hard to elucidate how birds use the region and what drives their movements in this vast network of coastal wetlands spanning 3,100 miles (5,000 kilomete