This picture is proof that the monarchs are entering Mexico. It was taken on the bank of the Rio Grande River, in the state of Chihuahua. The Rio Grande forms the border between the U.S. and Mexico. The mountain in the background is on the U.S. side of the border, in Big Bend National Park. Three hundred monarchs were nectaring here last week on flowering shrubs that grow near water sources in the Chihuahua desert.
Photo by Biologist Paul Nava, Profauna Chihuahua and courtesy of Rocio Trevino, Correo Real.