I was sitting at a favorite spot at El Rio Preserve where there is a small and brushy island perhaps ten feet from the shore. In the morning the sunlight was behind me making it a good location for taking photos of any birds in the trees. It was a quiet morning when suddenly, from the back side of the island, I saw a large Great Blue Heron flying off with something huge in its bill. When it disappeared to my right I ran to the other side of the peninsula where I had been sitting. I got there and saw the Great Blue Heron across the water holding a huge American Bullfrog in its bill
A pink wound was visible on the head of the bullfrog. That was where the Heron had stabbed the frog to subdue it. I watched as the Great Blue Heron held the bullfrog, and then dropped it into the water and let it go. After a few seconds, it dipped its bill into the water and picked the bullfrog up again.
The Heron continued this behavior: alternately dropping the bullfrog into the water, waiting a few seconds, and then picking it up once more. I never saw any indication that the bullfrog was still alive and I had no idea what the heron was doing.
Sometimes the Great Blue would turn in the other direction and then, after a moment, either drop or dip the frog in the water, wait a bit, and then pick it up once more.
A study in Oregon indicated that the average length of the beak of a Great Blue Heron was 5.5 inches long. That gives you a sense of how big and long the bullfrog is. Great Blue Herons themselves are about 4 to 5 feet in length (measured from the tip of their bill to the tip of their tail.) As large as they are, they may only weigh 5 to 6 pounds.
Occasionally the Heron would pick up the bullfrog by its legs. This pre-meal behavior is mentioned quite a bit so it is common for a Great Blue Heron to do this. The purpose is still not clear. Is it ensuring its prey is clean of any debris? The bullfrog was definitely passive and dead already. Whatever the reason, it was fascinating to watch.
I never knew that the underside of these bullfrogs were spotted.
The Heron continued this behavior for quite a while- eight minutes in fact while I was observing it. In my next email, you'll learn what happened next.
Happy Thanksgiving!