Browsing by Author "Martinez, David R."

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    FOOD HABITS AND TROPHIC ATTRIBUTES OF THE MAGELLANIC HORNED OWL (BUBO MAGELLANICUS) IN THE PATAGONIAN STEPPE, SOUTHERNMOST CHILE
    (2020) Martinez, David R.; Alvarez-Cortez, Gabriela; Jaksic, Fabian M.
    For most of southern South America, the food habits of Magellanic Horned owls (Bubo magellanicus) are well known. In Chile, several researchers have reported the owl's diet in northern xerophytic environments, as well as subpolar forests; however, other than a short note on the owls' summer diet in Punta Dungeness (Martinez 2018), no major studies have documented the food habits of Magellanic Horned owls in the Chilean Patagonian steppe. Based on 278 fresh pellets, we reported the food habits of owls inhabiting two sites located at > 52 degrees S in the southernmost Patagonian steppe in continental Chile, and compared our findings with those reported for owls inhabiting eight localities from 39 to 52 degrees S in the Argentinean Patagonian steppe. Our results indicate that in Patagonian steppe environments of both Argentina and Chile, the Magellanic Horned Owl is a generalist predator, which consumes whatever prey available, ranging in size from invertebrates to introduced juvenile lagomorphs. Because all five major vertebrate prey here reported (Abrothrix olivacea, Loxodontomys micropus, Microcavia australis, Reithrodon auritus, Lepus europaeus) are broadly distributed in the Argentinean Patagonian steppe and occur abundantly from 36 degrees S southwards to the Strait of Magellan and Isla Grande de Tierra del Fuego, their generalized occurrence as prey does not allow for expression of latitudinal trends in species composition in the owl's diet.
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    Historical account and current knowledge of the southernmost Chiropterofauna in the world: the Magellanic/Fuegian bats
    (2023) Jaksic, Fabian M.; Martinez, David R.
    A depauperate Chiropterofauna consisting of essentially three bat species (the year-round residents Histiotus magellanicus and Myotis chiloensis, and the apparently migratory Lasiurus varius), exists in the challenging cold and windy environment of the Magellanic/Fuegian region, which encompasses territories in Argentina and Chile, both continental and insular. Knowledge of that bat fauna benefitted from earlier explorers and naturalists visiting such southerly and isolated geographical confines, but still lacks a comprehensive scientific study, particularly in face of expected green-energy projects using aerogenerators known to cause bat fatalities elsewhere. Currently, there is a paucity of information on the fine-scale geographic distribution, local abundance, and migration patterns of those bats that needs to be remedied as soon as possible. Our review may aid orienting and focusing such a research program, which should hopefully be binational, on account of the artificial nature of the border between Argentina and Chile in Tierra del Fuego.
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    The currently known distribution of the Austral Patagonian and Fuegian bats
    (2024) Jaksic, Fabian M.; Martinez, David R.
    We report the currently existing 31 records for Austral Patagonian and Fuegian bats spanning from 1866 to 2022. The Vespertilionidae were: Myotis chiloensis , Histiotus magellanicus , and Lasiurus varius , and the Molossidae was Tadarida brasiliensis . The former two species were recorded at forested sites along a swath that runs NW-SE for about 670 km from Torres del Paine in continental Magallanes to Tierra del Fuego and Navarino islands. Those forests were Coihue-Canelo (Nothofagus betuloides-Drymis winteri) , Coihue-Lenga (N. betuloides-N. pumilio ), Lenga ( N. pumilio-Maytenus disticha ), or & Ntilde;irre shrubland ( N. antarctica-Chiliotrichum difussum ). Only one record for each of Lasiurus varius , Histiotus magellanicus, and Tadarida brasiliensis were located in steppe environments of Festuca gracillima-Chiliotrichum difussum but were centered at human habitations and surrounding orchards or plantations, and their presence therein may be deemed accidental.