Madrean Sky Islands of

The Madrean Sky Islands are exclaves of medium to high elevation Madrean pine-oak woodland, located on small mountain ranges in southeastern Arizona, southwestern New Mexico, northeastern Sonora and northwestern Chihuahua, being separated from each other by the Sonoran or Chihuahuan Deserts.

Twenty-seven sky islands are located within southwestern United States while a further fifteen occur in northern Mexico.


Map showing the Madrean Sky Islands of Arizona, New Mexico, Sonora and Chihuahua.
This map was adapted from an excellent map of the Sky Islands by Sky Jacobs at

National and state borders are added, mountain ranges and towns visited are highlighted in yellow.
Click to enlarge map.

The Sky Islands are renowned for their unique floras and faunas, not least their herpetofaunas. Amongst the most interesting of their resident reptiles are the small montane rattlesnakes. Mottled rock rattlesnakes (Crotalus lepidus lepidus), Banded rock rattlesnakes (Crotalus lepidus klauberi) Twin-spotted rattlesnakes (Crotalus pricei pricei), Arizona ridgenose rattlesnakes (Crotalus willardi willardi) and New Mexico ridgenose rattlesnakes (Crotalus willardi obscurus) inhabit in the Sky Islands of the United States while these and other species occur in the Mexican ranges to the south. Vulnerable and potentially endangered, these taxa are protected by state and federal laws in the US and Mexico.

But the chance to see these small and secretive rattlesnakes in the wild is the reason many herpetologists and herpetoculturists make visits to the Southwest.

We had already tried and failed to gain entry to the Chiricahua Mountains of southeastern Arizona but the fire damage had meant access was closed to all vehicles above Portal. Bob, Tell and I drove further along the Chiricahuas and discovered the same situation with even walkers access forbidden due to the wildfire damage.

It now being the top of the day we stopped in Sierra Vista for lunch and spent a couple of an hours in the cinema, watching Cowboys and Aliens!

Then we headed for Sonoita to link up with Frank Retes and explore the Huachuca and Santa Rita Mountains. We were accompanied on our drive by a CD of Bob Dylan's The Saga of Pat Garrett & Billy the Kid, picked up in Sierra Vista, highly appropriate background for driving through this part of the Southwestern deserts.