Certain seabirds drawn by the smell of food.Some inconspicuous seabirds, such as prions prion /pri·on/ (pri´on) any of several transmissible forms of the core of prion protein that cause a group of neurodegenerative diseases. Prions differ in structure from normal prion protein, lack detectable nucleic acid, and do not elicit an immune response. and white-chinned petrels petrel (pĕ`trəl), common name given various oceanic birds belonging, like the albatross and the shearwater, to the order known commonly as tube-nosed swimmers. There are two families of petrels: the storm petrels storm petrel: see petrel. (Hydrobatidae) and the diving petrels (Pelecanoididae)., behave like the bloodhounds bloodhound, breed of large hound whose ancestors were known in the Mediterranean region before the Christian era. It stands about 25 in. (63.5 cm) high at the shoulder and weighs between 80 and 110 lb (36.3–49.9 kg). Its short, smooth coat may be black and tan, red and tan, or tawny. The skin is very loose and hangs in deep folds over the forehead and at the sides of the face, giving the dog its characteristically mournful expression. of the Antarctic skies, a new study suggests. These birds apparently use their sense of smell to track down food in the vast expanse of the South Atlantic Ocean, Gabrielle A. Nevitt of the University of California, Davis, and her colleagues assert in the Aug. 24 Nature. The birds may locate zooplankton, tiny ocean animals that they feed on, by following the odor of dimethyl sulfide (DMS DMS - Defense Message System DMS - Degrees, Minutes, Seconds DMS - Dartmouth Medical School (Hanover, NH, USA) DMS - Data Management Services DMS - Data Management Simulator DMS - Data Management Software DMS - Data Management Subsystem DMS - Data Management System DMS - Data Manipulation System DMS - Data Multiplex System (US Navy AN/USQ-82(V)) DMS - Dealer Management System DMS - Dealership Management System), which gets released when zooplankton graze on phytoplankton (single-celled plants). The team estimates that these birds can detect normal ambient concentrations of DMS from up to 4 kilometers away. Ornithologists have only recently accepted the idea that birds can smell at all, and most researchers who study their foraging techniques ignore the significance of odors, contends Bernice M. Wenzel, of the University of California, Los Angeles, School of Medicine. DMS has also piqued the interest of climatologists, who are debating whether the compound could increase the concentration of cloud-forming particles in the atmosphere and alter temperatures (SN: 12/10/88, p. 375). From their ship, Nevitt and her colleagues sprayed both a DMS-scented and an unscented aerosol plume into the air. They also poured out cod-liver oil cod-liv·er oil (k d l v and unscented and DMS-scented vegetable oil, which formed slicks on the water. Concentrations of DMS resembled what the birds might naturally encounter. On average, twice as many birds came to the DMS-scented slicks as the unscented oil, and they found the scent as enticing as cod-liver oil. The birds zigzagged over the DMS slick, sat on it, tasted it, or just hovered over it. Although white-chinned petrels, prions, and two species of storm petrels found the DMS compelling, albatrosses albatross (ăl`bətrôs), common name for sea birds of the order of tube-nosed swimmers (Procellari-iformes), which includes petrels, shearwaters, and fulmars. and cape petrels showed no particular interest in it. The researchers obtained similar responses with the plumes. All of the studied birds belong to the order Procellariiformes, and have unusually large areas in their brains responsible for smell. The authors speculate that species showing no preference for DMS may have detected the odor but not considered it a food cue. Such birds may instead rely more on visual cues--finding food by watching where others head. Unlike the DMS-sensitive birds, the nonresponders nonresponder /non·re·spond·er/ (non-re-spon´der) a person or animal that after vaccination against a given virus does not show any immune response when challenged with the virus. are quite visible, forage mostly by day, and join large feeding groups, Nevitt observes. The scientists are investigating whether blacked-brow albatrosses space themselves differently than do the DMS-sensitive birds in order to watch each other. "We're just wondering whether they hunt differently," Nevitt says. Other studies have shown that birds will follow odors, such as ground-up squid and fish oil. But "it's rare to see such a pronounced response to such a pure aromatic [as DMS]," Nevitt says. Indeed, the strength of this study stems from its use of a natural odorant odorant /odor·ant/ (o´der-int) any substance capable of stimulating the sense of smell., agrees Jerry A. Waldvogel of Clemson (S.C.) University. |
|
||||||||||||||||||||

d
l
v
Printer friendly
Cite/link
Email
Feedback
Reader Opinion