Mongoose myths dispelled in new series
Mar 28, 2007 |
Pacific Science, the quarterly journal published by the University of Hawai’i, has launched a new series, ‘Biology and the Impacts of Pacific Island Invasive Species.’
Warren S.T. Hays and Sheila Conant, both professors at UH-Manoa, co-authored the inaugural study, a global overview of the impacts of mongoose on island ecosystems. Their findings suggest that mongoose, though widely blamed for extinctions of ground-nesting birds, is in fact responsible for the extinctions of just three vertebrate species–the barred-wing rail, the Jamaica petrel and the Hispaniola racer. ‘And in each of those cases, there is room for doubt,’ the authors add.
‘The degree to which mongooses are responsible for the historical decline of bird species is often hard to assess,’ the authors write, ‘because of exacerbating factors such as introduction of rats, cats, dogs and pigs, and habitat encroachment by human communities. It must be noted that any bird species now living in the presence of mongoose populations in Hawai’i has been doing so for over a century. It has been suggested that ground-nesting bird populations have established a predator-prey equilibrium with mongooses in the CaribbeanÖThis may also be true in Hawai’i, though it is surely also true that the mongoose’s presence poses a substantial barrier to reestablishment of ground-nesting bird populations in their historical ranges.’
Hays and Conant discount the ‘common story in Hawai’i that small Indian mongooses failed to control rats in areas of introduction because the mongoose is diurnal and rats are primarily nocturnalÖMost published accounts dispute this story, asserting that the small Indian mongoose served as an excellent cane-field ratterÖ, though it was eventually made obsolete by the development of improved techniques of rat poisoning.’
The idea that wild mongooses and feral cats might compete for food also is challenged. ‘Feral cats and wild mongooses peacefully share food at artificial feeding sites on O’ahu, feeding within centimeters of each other,’ the authors write. On June 3, 1999, Hays ‘observed two large male mongooses pass together within 3 m[eters] of an adult feral cat, in a relatively undisturbed woodlot and apparently by coincidence, without any of the animals involved showing any sign of excitement or stress even while making eye contact.’
