Azorean bats Nyctalus azoreum, cluster as they emerge from roosts, despite the lack of avian predators

• Autorzy: Irwin N.R. , Speakman J. R.
• Języki publikacji: EN

Abstrakty

EN

We tested the hypothesis that clustering in the behaviour of emerging bats is a response to the risk of avian predation. We hypothesised that if avian predation was the cause of clustering, bats in the prolonged absence of avian predators, would not cluster or would cluster less during their emergences. We studied the Azorean bat (Nyctalus azoreum) in the Azores Archipelago. The Azores have a depauperate fauna with no raptorial birds likely to predate bats. The Azorean bat is an endemic mammal to the archipelago, which has an unusually extensive degree of diurnal activity that has been hypothesised to reflect release from the risk of diurnal predation by raptors. Contrary to our prediction Azorean bats clustered during emergence to the same extent as bat species which occur where there are raptors. Two interpretations of these data are possible. First, the hypothesis that the behaviour is anti-predatory may be incorrect. Most of the variation in clustering was explained by variation in ambient temperature possibly suggesting the bats emerged in groups to aid exploitation of sparsely distributed food. Alternatively, the behaviour may be anti-predatory, but the key factor precipitating clustering may not be the risk from aerial predators, but terrestrial predators, such as rats (Rattus norvegicus) and cats (Felis cattus), both of which were common around the roost sites.

• Wydawca: -
• Czasopismo: Acta Chiropterologica
• Rocznik: 2003
• Tom: 05
• Numer: 2
• Opis fizyczny: p.185-192,fig.,ref.

Twórcy

autor

Irwin N.R.

• School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, Great Britain

autor

Speakman J. R.

Bibliografia

• Avery, M. I., P. A. Racey, and M. B. Fenton. 1984. Short distance location of hibernaculum by little brown bats (Myotis lucifugus). Journal of Zoology (London), 204: 588-590.
• Barak, Y., and Y. Yom Tov. 1989. The advantage of group hunting in Kuhl’s bat (Pipistrellus kuhli) (Microchiroptera). Journal of Zoology (London), 219: 670-675.
• Bannerman, D. A., and W. M. Bannerman. 1966. Birds of the Atlantic islands. 3. A history of birds of the Azores. Oliver and Boyd, Edinburgh, 262 pp.
• Bullock, D. J., B. A. Combes, L. A. Eales, and J. S. Pritchard. 1987. Analysis of the timing and pattern of emergence of the pipistrelle bat (Pipistrellus pipistrellus). Journal of Zoology (London), 211: 261-21 A.
• Fenton, M. B., I. L. Rautenbach, S. E. Smith, C. M. Swanepoel, J. Grosell, and J. Van Jaarsveld. 1994. Raptors and bats: threats and opportunities. Animal Behaviour, 48: 9-18.
• Fenton, M. B. 1995. Constraint and flexibility — bats as predators, bats as prey. Symposia of the Zoological Society of London, 67: 277-289.
• Gillette, D. D., and J. D. Kimbourgh. 1970. Chiropteran mortality. Pp. 262-281, in About bats (B. H. Slaughter and D. W. Walton, eds.). Dallas Southern Methodist University Press, Dallas, 339 pp.
• Jones, G., P. L. Duverge, and R. D. Ransome. 1995. Conservation biology of an endangered species: Field studies of greater horseshoe bats. Symposia of the Zoological Society of London, 67: 309-324.
• Hamilton, W. D. 1964. Geometry of the selfish herd. Journal of Theoretical Biology, 31: 295-311. Kalcounis, M. C., and R. M. Brigham. 1994. Impact of predation risk on emergence by little brown bats, Myotis lucifugus (Chiroptera: Vespertilionidae), from a maternity colony. Ethology, 98: 201-209.
• McAney, C., and J. Fairley. 1990. Activity of Leisler’s bat Nyctalus leisleri (Kuhl, 1818) at a summer roost in Ireland. Myotis, 23: 83-92.
• Moore, N. W. 1975. The diurnal flight of the Azorean bat (Nyctalus azoreum) and the avifauna of the Azores. Journal of Zoology (London), 177: 483-506.
• Negro, J. J., C. Ibaňez, J. L. Perez Jorda, and M. J. Delaviro. 1992 Winter predation by common kestrel Falco tinnunculus on pipistrelle bats (Pipistrellus pipistrellus) in southern Spain. Bird Study, 39: 195-199.
• Palmeirim, J. M. 1991. A morphometric assessment of the systematic position of the Nyctalus from the Azores and Maderia (Mammalia: Chiroptera). Mammalia, 55: 381-387.
• Petrželkova, K. J., and J. Zukal. 2001. Emergence behaviour of the serotine bat (Eptesicus serotinus) under predation risk. Netherlands Journal of Zoology, 51:395-414.
• Petrželkova, K. J., and J. Zukal. 2003. Does a live barn owl (Tyto alba) affect emergence behavior of serotine bats (Eptesicus serotinus)? Acta Chiropterologica, 5: 177-184.
• Rydell, J., A. C. Entwistle, and P. A. Racey. 1996. Timing of foraging flights of three species of bats in relation to insect activity and predation risk. Oikos, 76: 243-252.
• Speakman, J. R. 1990. The function of daylight flying in British bats. Journal of Zoology (London), 220: 101-113.
• Speakman, J. R. 1991. Why do insectivorous bats in Britain not fly in daylight more frequently? Functional Ecology, 5: 518-524.
• Speakman, J. R. 1993. Clustering in the emergence behavior of bats: Some pitfalls in analysis and how to overcome them. Bat Research News, 34: 49-54.
• Speakman, J. R. 1995. Chiropteran nocturnality. Symposia of the Zoological Society of London, 67: 187-201.
• Speakman, J. R., and P. I. Webb. 1993. Taxonomy, status and distribution of the Azorean bat (Nyctalus azoreum). Journal of Zoology (London), 231: 27-38.
• Speakman, J. R., D. J. Bullock, L. A. Eales, and P. A. Racey. 1992. A problem defining temporal pattern in animal behaviour: clustering in the emergence behaviour of bats from maternity roosts. Animal Behaviour, 43: 491-500.
• Speakman, J. R., L. F. Lumsden, and G. C. Hays. 1994. Predation rates on bats released to fly during daylight in southeastern Australia. Journal of Zoology (London), 233: 318-321.
• Speakman, J. R., R. E. Stone, and J. E. Kerslake. 1995. Temporal patterns in the emergence behaviour of pipistrelle bats, Pipistrellus pipistrellus, from maternity colonies are consistent with an anti-predator response. Animal Behaviour, 50: 1147-1156.
• Speakman, J. R., N. R. Irwin, N. Tallach and R. Stone. 1999. Effect of colony size on the emergence behaviour of pipistrelle bats (Pipistrellus pipistrellus): intra- and inter roost effects. Animal Behaviour, 58: 787-795.
• Swift, S. M. 1980. Activity patterns of pipistrelle bats (Pipistrellus pipistrellus) in northeast Scotland. Journal of Zoology (London), 190: 285-295.
• Ulfstrand, S. 1961. On the vertebrate fauna of the Azores. Biological Bulletin of the Municipal Museum at Funchal, 14: 75-86.
• Ward, P., and A. Zahavi. 1973. The importance of certain assemblages of birds as ‘Information centers’ for food-finding. Ibis, 115: 517-534.
• Wilkinson, G. S. 1992. Information transfer at evening bat colonies. Animal Behaviour, 44: 501-518.
• Wilkinson, G. S. 1995. Information transfer in bats. Symposia of the Zoological Society of London, 67: 345-360.
• Wilkinson, G. S., and J. W. Boughman. 1998. Social calls coordinate foraging in greater spear-nosed bats. Animal Behaviour, 55: 337-350.

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