Today we explored the two extremes of Baja California. On one end of the spectrum, we visited Isla San Esteban, home to two reptiles found nowhere else on earth: the spiny-tailed iguana and the San Esteban chuckwalla. These endemic species are prime examples of how island biogeography in the Sea of Cortez influences biologic diversity and, similarly, small populations of unique animals.

On the other extreme was our afternoon destination, Isla Rasa. Over a half million pairs of Heermann’s gulls and elegant terns share close quarters after migrating from wintering grounds to the north and south of Baja, respectively. The huge number of birds we saw this afternoon contrasted wonderfully with our morning search for one of the planet’s most isolated populations.