May 1, 2000.
The Swallow-Tailed Gull Appears
This is Roger Payne aboard the Odyssey, speaking to you from the Galapagos Islands.
This is Roger Payne speaking to you from the Odyssey.
Last night I quoted an excerpt from a letter I had written to my wife in 1994 about watching stars from the deck of the sailing ketch the Rachel III as it made a night passage in the waters around the Galapagos islands. Tonight I am in these waters again, this time in my institute's own boat, the Research Vessel Odyssey. The end of my letter to Lisa will introduce an extraordinary night bird that I had never seen nor heard of before.
"It was while mulling over the motion of the mast against the stars that I fell into a deep sleep and dreamed of you. I was awakened about four hours later by drops of water on my face. The wind had freshened, and the moon, in its final quarter, was up. But there were now clouds which made the moonlight faint, and gray, and cold. As I looked forward to see what islands might be visible I started at the sight of a bird flying just ahead of the boat. It flew with effortless skill, almost, but never quite touching the forestay, and every ten minutes or so shearing off to dive at the surface of the sea. I realized that it was chasing small creatures disturbed by our passage - presumably tracking them by their phosphorescent wakes. It was in size intermediate between a gull and a tern but its flight was more reminiscent of a tern. It was obviously a white bird with black markings but I could not see the pattern clearly.
"I watched it in delight for about an hour, but in my half asleep state I began to imagine that this strange night bird was you - was your spirit flying ahead of our boat, guiding me back to you. So vivid did that feeling become that I found myself swept with emotion and in my half dream wept as I watched you flying unreachably ahead. It was a strange and mystical thing, the perfect creature with which to mix waking and sleep.
"It was, as I found out the following morning, a swallowtail gull, a species endemic to the Galapagos and to one small island off Colombia-one of the few seabirds that hunts at night. An Odyssey crew member who was returning with me said that these birds often accompany the Odyssey and that he thinks they use the faint light from the boat's running lights to see their prey, hunting mostly on the starboard side where the light is green rather than on the port where it is red-birds see green better than red. I suppose that these gulls are forced to hunt at night so as to avoid the canopy of frigate birds who make their living by robbing seabirds of their catch."
And that was where my letter to Lisa stopped and where my knowledge of these birds stopped too until this present journey to Galapagos, when, only tonight I was shocked by a new revelation about these birds.
We had stopped Odyssey to have a peaceful dinner on the aft deck table, and as we sat chatting in the perfectly calm, black night, someone said "There's a swallowtail gull, and it's making its sounds: I've heard they echolocate." I was stunned...for several reasons. First; I had not heard that they echolocated, i.e. that they make sounds that might be used for orientation or perhaps even locating prey. Second, I my very first job, as an undergraduate, and at the start of my career in biology, was feeding bats for Donald Griffin, the man who first discovered that bats and oil birds echolocate. And third, I had not seen this wonderful, mystical spirit-of-a-bird for six years. As I listened to its sounds it fluttered softly about the boat, briefly hovering above the water, and occasionally dropping down to catch a fish. I knew Don Griffin would love to hear its sounds so Chris Johnson got out his recorder and everyone stayed silent for about half an hour while we listened to it. During this time the single gull was joined by 8 more, all of which fished enthusiastically along side it off the port stern of the boat where our rigging lamps cast most light. And all the time these birds made their sounds and Chris recorded them.
Their clicks surely sound like prime candidates for echolocation to me though also could be social sounds. I heard nothing from the first lone bird I watched, fishing ahead of the Rachel III, and I heard most clicking tonight when the birds were clustered together. I'm dying to find out more.
This is what they sounded like. To recreate the conditions of this recording in your mind you must imagine a gently rocking boat, a glassy sea, a canopy of stars, and 9 silently flying, spirit birds hovering about you in the semi-darkness, making their unearthly clicks.
God, nights at sea can be pleasant!
© 2000 - Roger Payne