Browsing by Author "YANEZ, JL"

Now showing 1 - 4 of 4
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    2 TYPES OF ADAPTATION OF VERTEBRATE PREDATORS TO THEIR PREY
    (1979) JAKSIC, FM; FUENTES, ER; YANEZ, JL
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    BODY-SIZE OF CHILEAN FOXES - A NEW PATTERN IN LIGHT OF NEW DATA
    (1995) JIMENEZ, JE; YANEZ, JL; TABILO, EL; JAKSIC, FM
    By using body measurements and weight data of culpeo fox Dusicyon culpaeus Molina, 1782 and chilla fox D. griseus Gray, 1837 from the Chinchilla National Reserve (north-central Chile) and Torres del Paine National Park (southern Chile), the body size distribution of Chilean foxes was analyzed and compared to data previously published by Fuentes and Jaksic (1979). Contrary to those authors, our data show that not only the larger but both species increase in size in southern Chile. Thus, latitudinal size distribution of D. culpaeus and D. griseus may not be the result of character displacement through exploitation competition, as previously interpreted, but of bioenergetic adaptations.
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    DISCOVERY OF A CONTINENTAL POPULATION OF THE RARE DARWIN FOX, DUSICYON-FULVIPES (MARTIN, 1837) IN CHILE
    (1990) MEDEL, RG; JIMENEZ, JE; JAKSIC, FM; YANEZ, JL; ARMESTO, JJ
    The rare Darwin''s fox Dusicyon Fulvipes (Martin, 1837) was thought to be restricted to Chiloe Island in southern Chile, and to be a subspecies of Dusicyon griseus. We report the findings of a continential population of D. fulvipes, 600 km north of its known insular ranges and in sympatry with D. griseus. We document for the first time the food habits of Darwin''s fox, add new information on its morphometry, and discuss the systematic, zoogeographic and ecological implications of the discovery of the continental population.
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    PREY OF THE WHITE-TAILED KITE IN CENTRAL CHILE AND ITS RELATION TO THE HUNTING HABITAT
    (1980) SCHLATTER, RP; TORO, B; YANEZ, JL; JAKSIC, FM
    Between Nov. 1973 and Jan. 1974 702 pellets of white-tailed kites (E. lecurus) in 2 areas of central Chile differing in their vegetation physiognomy (disturbed vs. undisturbed) were collected. The diversity, age structure and mean prey size of items found in pellets from both sites were compared. There were noticeable differences in the diversity of prey consumed by kites in the 2 areas. The smallest prey taken was the house mouse (17 g), the largest, juvenile norway rats (160 g); these figures represent 5.6-52.9% of Chilean kites'' weight (302.2 g). Mean size of prey taken in the disturbed site was about 25% smaller than in the undisturbed area. White-tailed kites were much more abundant in disturbed areas, in spite of the relatively smaller prey-size distribution available. Disturbed habitats generated by human activities may be more profitable to the kites in terms of greater prey abundance, higher prey vulnerability, or both.