FEEDING BEHAVIOR OF THE HUMPBACK WHALE, MEGAPTERA NOVAEANGLIAE, IN THE WESTERN NORTH ATLANTIC
Observations on the feeding behavior of the humpback whale, Megapteranovaeangliae, were made from aerial and surface platforms fTom 1977 to 1980 in the continental shelf waters of the north­ eastern United States. The resulting catalog of behaviors includes two principal categories: Swim­ ming/lunging behaviors and bubbling behaviors. A behavior from a given category may be used independently or in association with others, and by individual or groups of humpbacks. The first category includes surface lunging, circular swimming/thrashing, and the "inside loop" behavior. In the second category, a wide variety of feeding-associated bubbling behaviors are described, some for the first time. The structures formed by underwater exhalations are of two major types: 1) bubble cloud-a single, relatively large (4-7m diameter), dome-shaped cloud formed of small, uniformly sized bubbles; and 2) bubble column-a smaller (1-1.5 m diameter) structure composed of larger, randomly sized bubbles, used in series or multiples. Both basic structures are employed in a variety of ways. Many of these behaviors are believed to be utilized to maintain naturally occurring concentrations of prey, which have been identified as the American sand lance, Ammodytes americanus, and occasionally as herring, Clupea harengus. This paper reports on the feeding behavior of the humpback whale, Megaptera novaeangliae, in the continental shelf waters of the northeastern United States. We describe several feeding be­ haviors reported for the first time, as well as a number of behaviors known from other areas but not previously reported for these waters. Our col­ lective observations provide the beginning of a more complete catalog than has previously been available.