First application of satellite telemetry to track African straw-coloured fruit bat migration H. V. Richter 1 & G. S. Cumming 1,2 1 Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA 2 DST/NRF Center of Excellence, Percy FitzPatrick Institute, University of Cape Town, Rondebosch, Cape Town , South Africa Keywords Chiroptera; migration; seed dispersal; frugivory; Africa; Zambia; Congo; satellite telemetry. Correspondence Graeme S. Cumming, DST/NRF Center of Excellence, Percy FitzPatrick Institute, University of Cape Town, Rondebosch, Cape Town 7701, South Africa. Email: graeme.cumming@uct.ac.za Editor: Virginia Hayssen Received 7 November 2007; revised 25 January 2008; accepted 25 January 2008 doi:10.1111/j.1469-7998.2008.00425.x Abstract Despite long-standing awareness of the potentially important ecological role of fruit bats, we know little about the ecology of the vast majority of species. Here we report the results of a pilot satellite tracking study aimed at establishing the scale of movement of the straw-coloured fruit bat Eidolon helvum. This was the first ever attempt to track African fruit bats using satellite telemetry. We tagged four bats with solar-charged 12 g satellite transmitters at Kasanka National Park in December 2005 and obtained a combined total of 104 different location fixes over a 149-day period. Before migrating, bats foraged as far as 59 km from the roost in a single evening; by contrast, one migrating individual moved 370 km in one night. Bats travelled an average 29 km day 1 over the period of study, with bats that appeared to be migrating moving north-west from Kasanka at an average 90 km day 1 . The greatest cumulative distance travelled by a single bat was 2518 km in 149 days. The results show conclusively that the straw-coloured fruit bat E. helvum is capable of migrating thousands of kilometres across central Africa on an annual basis, implying that the fruit pulse in northern Zambia is richer than anything on offer in the Democratic Republic of the Congo at the same time of the year. Introduction Fruit bats (Megachiroptera) occur in many African ecosys- tems in large numbers. Fruit bats play an important ecolo- gical role in the pollination of flowering plants, the dispersal and germination of seeds and the subsequent establishment of woody vegetation (Taylor & Kankam, 1999; Medellin & Gaona, 1999; Henryi & Jouard, 2007). Although many of the functions of bats are also performed by birds, some woody plants in Africa are almost entirely bat pollinated, and because the dispersal behaviours of fruit bats differ from those of birds, bats provide additional redundancy in these keystone ecological processes (Walker, 1992; Naeem, 1998; Duncan & Chapman, 1999). An estimated 5–10 million straw-coloured fruit bats Eidolon helvum congregate between October and December each year at Kasanka National Park in north-central Zambia (Sorensen & Halberg, 2001; Richter & Cumming, 2006). The Kasanka colony (Fig. 1) is one of the largest known aggregations of fruit bats in the world. Straw-coloured fruit bats are found either year round or seasonally throughout much of sub-Saharan Africa, but there has been little previous research on their broad-scale movement patterns (or indeed, on those of any African fruit bat, Thomas, 1983). The broad-scale ecological role played by fruit bats in African savannas is largely unexplored, and as a result the potential contributions of fruit bats to ecosystem processes remain extremely difficult to assess. We argued previously that straw-coloured fruit bats at Kasanka National Park migrate south from equatorial rainforests to take advantage of a seasonal pulse of fruit production in northern Zambia (Richter & Cumming, 2006). Our initial results showed that the timing of fruit bat arrival and departure matched closely the periods of in- crease and decrease in fruit availability at Kasanka National Park. However, this work (which was conducted solely at Kasanka National Park) was not sufficient on its own to determine the distances over which bats were responding to fruit availability. In this follow-up study, we test the hypothesis that the scale of E. helvum movements in southern Africa is similar to that of broad-scale spatial variation in rainfall and conse- quently in fruit production. Broad-scale (latitudinal) varia- tions in rainfall and plant phenology are well documented and relate closely to fruit production and to the reproductive strategies of bats (Hepburn & Radloff, 1995; Cumming & Bernard, 1997). If the mechanism driving E. helvum move- ments is a response to fruit availability, we expect that bats would move over large areas between rainfall regions to exploit spatial and temporal variations in fruit production. The alternative hypothesis suggests that the bats remain within the same rainfall region [i.e. are derived from the southern Democratic Republic of the Congo (DRC) and eastern Zambia] but aggregate annually at Kasanka Na- tional Park. This study constituted both a pilot project to Journal of Zoology Journal of Zoology 275 (2008) 172–176 c  2008 The Authors. Journal compilation c  2008 The Zoological Society of London 172 Journal of Zoology. Print ISSN 0952-8369