Acoustic monitoring on a humpback whale (Megaptera novaeangliae) feeding ground shows continual singing into late Spring.
Singing by males is a major feature of the mating system of humpback whales, Megaptera novaeangliae (Borowski). Although a few songs have been opportunistically recorded on the whales' high-latitude feeding grounds, singing in these regions was thought to be only sporadic. We report results from the first continuous acoustic monitoring of a humpback whale feeding ground (off Cape Cod, MA, USA) in spring. Using autonomous sea-floor recording systems, we found singing on a daily basis over the entire 25 day monitoring period, from 14 May to 7 June 2000. For much of the period, song was recorded 24 h per day. These results, combined with evidence for aseasonal conceptions in whaling catch data, suggest that the humpback whale breeding season should no longer be considered as confined to lower-latitude regions in winter. Rather, we suggest breeding extends geographically and temporally onto feeding grounds into at least spring and early summer. Singing at these times represents either low-cost opportunistic advertising by (perhaps relatively few) males to court females that failed to conceive during the winter, and/or possibly an intrasexual display.
Clark
Christopher W
CW
Bioacoustics Research Program, Laboratory of Ornithology, Cornell University, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA. cwc2@cornell.edu
Clapham
Phillip J
PJ
D000818:Animals; D001267:Atlantic Ocean; D005247:Feeding Behavior / Q000502:physiology*; D005843:Geography; D012621:Seasons; D012726:Sexual Behavior, Animal / Q000502:physiology*; D013018:Sound Spectrography; D013997:Time Factors; D014828:Vocalization, Animal / Q000502:physiology*; D014907:Whales / Q000502:physiology*