HAIN ET AL.: FEEDING BEHAVIOR OF HUMPBACK WHALE 







feeding events, repeated occurrence in known 

 feeding areas, and the presence of feeding birds) 

 is strongly suggestive of a feeding-associated be- 

 havior. 



Bubble clouds were also observed being used 

 in series or multiples. These clouds possess the 

 characteristics described above but are used in 

 groups, generally three, by one or more hump- 

 backs. Two varieties have been seen (Fig. 3F, 

 G): 1) individuals or groups of humpbacks blow 

 clouds in either triangular or random patterns, 

 and feed in the midst of the clouds or within a 

 particular cloud— observed on a number of occa- 

 sions and considered relatively common; and 2) 

 an individual whale was seen to blow three lin- 

 early connected clouds, and then swim on the 

 surface very slowly through the formation- 

 observed on a single occasion and considered un- 

 common. 



A final variation, which may or may not be 

 directly associated with feeding, is poorly under- 

 stood. At times, a lunge-feeding whale will ex- 

 hale underwater, lunge feed to the surface, and 

 be followed shortly by one to three bubble clouds 

 appearing at the surface, closely adjacent to the 

 whale but arriving at the surface after the whale 

 instead of before, as described above. 



Behavioral Strategies 



Figure 5.— Aerial views of bubble cloud formation and asso- 

 ciated feeding. A. Dome-shaped bubble cloud, formed by 

 underwater exhalation, seen rising toward surface. B. Bub- 

 ble cloud after intercepting plane of surface— upper portion of 

 structure is flattened. C. Lunge-feeding whale appears 

 through center of bubble cloud. Photographs by A. Frothing- 

 ham. 



It has been our experience that a given hump- 

 back whale will generally repeat a fairly rigid 

 feeding pattern over a period of time. However, 

 several individual humpbacks or groups of 

 humpbacks feeding in the same area may or may 

 not display the same feeding strategy. Several 

 examples illustrate this observation. 



In two instances on Stellwagen Bank in 1978, 

 all humpback whales (five and seven individuals) 

 within a 20 km 2 area displayed bubble cloud 

 feeding (slow rise type) for an entire 1-h period of 

 observation. Every whale in sight appeared to be 

 using the same strategy. 



During two of the three observation periods on 

 one day in 1979, bubble clouds were formed by 

 one individual in the vicinity of extensive schools 

 of American sand lance, while three other 

 whales were lunge feeding (no bubbling asso- 

 ciated) several hundred meters away. 



On a third occasion, a single humpback on the 

 northern side of a school of American sand lance 

 was observed forming bubble clouds (with ap- 

 parent subsurface feeding), while three other 

 animals, working the same school of American 



265 



