They were missing. Then they used GPS tags to locate them.
That’s why the article is titled “ A Million Falcons Went Missing. Here’s How They Were Found”.
Something was unknown, then we used sensors to solve the mystery. Wild, isn’t it?
According to the dictionary definition of "missing", they were not missing.
At best, our assumptions about where we expected to find them were wrong.
I wish I could put gps tags on things after they go missing...