Midriff Region & Isla Rasa
The Midriff Region of the Gulf of California is an area of high productivity. Big islands with narrow, deep channels and large tidal variations account for very strong currents. Cold, nutrient rich water up wells, which leads to large schools of fish such as sardines and anchovies. These fish are fed on an incredible array of creatures that we spent the day observing.
The morning was spent cruising around Angel de la Guarda and La Partida islands. Feeding seabirds were abundant including nesting birds such as Least Storm-Petrels and Craveri’s Murrelets, and migrants such as Red-necked Phalaropes and Sabine’s Gulls. A few fin whales were observed, these second largest creatures probably feeding on the schooling fishes as well. Then a wonderful feeding frenzy was discovered. Boobies and pelicans were diving on fish that long-beaked common dolphins were feasting upon. We slowly followed this smorgasbord and watched the dolphins herd the fish and then switch to a more social behavior.
After lunch we visited Isla Rasa. This tiny little island is the nesting site for 95% of the world’s populations of Heerman’s Gulls and Elegant Terns, totaling somewhere near 400,000 birds. I wish I was able to somehow include the incredible noise that so many birds make, but no words can really describe the sounds of Isla Rasa. The birds were just returning to their nesting sites with the gulls staking out their individual spots all over the island. Meanwhile, the terns were gathering in mass along the shore and also gracefully flying overhead in paired display flights. So many birds in all directions became a blur of beating wings.
Walking on shore with the researchers and then cruising the shoreline in our fleet of Zodiacs allowed for the perfect end to our amazing day in the riches of the Midriff region.
