On Wednesday, Island Girl had a short migration day, traveling just 156 km (97 miles) WNW along the southern part of the isthmus of Tehuantepec, the narrowest continental crossing from the Pacific Ocean to the Gulf of Mexico.
She kept flying on this heading until she reached the southern end of the main Sierra Madre mountains near Oaxaca.
At this point, she roosted on the saddle of a hill at 1,671 ' elevation in dry forest.
She slept about 59 km (37 miles) inland from the Pacific and was about a quarter of the way across the isthmus.
It looks to me that she was just flying along until she ran into the mountains. At this point, they begin to curve northward, extending all the way up until they reach the Gulf just north of Veracruz.
Island Girl usually turns north here to reach the Gulf.
She is also likely to parallel this range along the east/north foothills traveling along the sweet spot just between the mountains and the Gulf.