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Great Blue Heron Swimming

Clarence Cottam

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While it is probable that most birds can swim when occasion requires, it is a novelty to see any of the larger waders demonstrating this inherent ability of their own free will and choice.

In company with Dr. Irvin Rasmussen, Mr. Cecil Williams, and Mr. Lee Kay, the writer saw this feat accomplished by a Treganza Blue Heron (Ardias herodias treganzai) at Gunnison Island, Great Salt Lake, Utah, July 12, 1938. It is believed that the individual was a bird of the year and that it probably had been raised on this island, which is about one mile long and a half mile wide. As the island is 30 to 40 miles from a source of food, it is probable that the bid had never ventured far beyond the confines of its homeland. When our company approaches, the bird took wing and flew in a semicircle over the mainland, alighting in the shallow brine some 30 yards from shore, whence it proceeded to walk into deeper water. On reaching water that was too deep for wading it began to swim with apparent ease and skill. It remained resting on the lake for about two hours, during which time it came much closer to shore, where we could easily observe it with binoculars. It was noted swimming in water that was probably not more than 6 or 8 inches deep. During this time its legs were held tightly against the body, but we could see that the feet were in motion. When, on one occasion, the writer approached the bird as it swam near shore, it promptly stood up and walked toward deeper water. More than half the length of the tarsus was then visible above the waterline. It is possible that the great buoyancy of thii nearly saturated water was an inducement to swimming.

United States Biological Survey, Washington, D. C., October 5, 1938

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