Kofa Saguaro (IMAGE) Ecological Society of America Caption Saguaro cacti are the tallest things standing at Kofa National Wildlife Refuge, near Yuma, Arizona. The cultural icon is a keystone species of the Sonoran Desert, serving as perch, nesting site, shelter, thermal refuge, and food for the birds and other animals in the desert ecosystem. Credit Taly Drezner Usage Restrictions with credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.