e-obs Stories & Publications

@article{smith_satellite_2011,

title = {Satellite Telemetry and Long-Range Bat Movements},

author = {Craig S. Smith and Jonathan H. Epstein and Andrew C. Breed and Raina K. Plowright and Kevin J. Olival and Carol De Jong and Peter Daszak and Hume E. Field},

editor = {Justin Brown},

url = {https://dx.plos.org/10.1371/journal.pone.0014696},

doi = {10.1371/journal.pone.0014696},

issn = {1932-6203},

year  = {2011},

date = {2011-02-01},

urldate = {2025-09-16},

journal = {PLoS ONE},

volume = {6},

number = {2},

pages = {e14696},

abstract = {Background: Understanding the long-distance movement of bats has direct relevance to studies of population dynamics, ecology, disease emergence, and conservation. 

Methodology/Principal Findings: We developed and trialed several collar and platform terminal transmitter (PTT) combinations on both free-living and captive fruit bats (Family Pteropodidae: Genus Pteropus). We examined transmitter weight, size, profile and comfort as key determinants of maximized transmitter activity. We then tested the importance of bat-related variables (species size/weight, roosting habitat and behavior) and environmental variables (day-length, rainfall pattern) in determining optimal collar/PTT configuration. We compared battery- and solar-powered PTT performance in various field situations, and found the latter more successful in maintaining voltage on species that roosted higher in the tree canopy, and at lower density, than those that roost more densely and lower in trees. Finally, we trialed transmitter accuracy, and found that actual distance errors and Argos location class error estimates were in broad agreement. 

Conclusions/Significance: We conclude that no single collar or transmitter design is optimal for all bat species, and that species size/weight, species ecology and study objectives are key design considerations. Our study provides a strategy for collar and platform choice that will be applicable to a larger number of bat species as transmitter size and weight continue to decrease in the future.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{holland_secret_2009,

title = {The Secret Life of Oilbirds: New Insights into the Movement Ecology of a Unique Avian Frugivore},

author = {Richard A. Holland and Martin Wikelski and Franz K\"{u}mmeth and Carlos Bosque},

editor = {Adrian L. R. Thomas},

url = {https://dx.plos.org/10.1371/journal.pone.0008264},

doi = {10.1371/journal.pone.0008264},

issn = {1932-6203},

year  = {2009},

date = {2009-12-01},

urldate = {2025-09-16},

journal = {PLoS ONE},

volume = {4},

number = {12},

pages = {e8264},

abstract = {Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees daylight, roosting in huge aggregations in caves during the day and bringing back fruit to the cave at night. As a consequence a large number of the seeds from the fruit they feed upon germinate in the cave and spoil. 

Methodology/Principal Findings: Here we use newly developed GPS/acceleration loggers with remote UHF readout to show that several assumptions about the behaviour of Steatornis caripensis need to be revised. On average, they spend only every 3rd day in a cave, individuals spent most days sitting quietly in trees in the rainforest where they regurgitate seeds. 

Conclusions/Significance:This provides new data on the extent of seed dispersal and the movement ecology of Steatornis caripensis. It suggests that Steatornis caripensis is perhaps the most important long-distance seed disperser in Neotropical forests. We also show that colony-living comes with high activity costs to individuals.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{rattenborg_sleeping_2008,

title = {Sleeping outside the box: electroencephalographic measures of sleep in sloths inhabiting a rainforest},

author = {Niels C Rattenborg and Bryson Voirin and Alexei L Vyssotski and Roland W Kays and Kamiel Spoelstra and Franz Kuemmeth and Wolfgang Heidrich and Martin Wikelski},

url = {https://royalsocietypublishing.org/doi/10.1098/rsbl.2008.0203},

doi = {10.1098/rsbl.2008.0203},

issn = {1744-9561, 1744-957X},

year  = {2008},

date = {2008-08-01},

urldate = {2025-09-16},

journal = {Biology Letters},

volume = {4},

number = {4},

pages = {402\textendash405},

abstract = {The functions of sleep remain an unresolved question in biology. One approach to revealing sleep's purpose is to identify traits that explain why some species sleep more than others. Recent comparative studies of sleep have identified relationships between various physiological, neuroanatomical and ecological traits, and the time mammals spend in rapid eye movement (REM) and non-REM sleep. However, owing to technological constraints, these studies were based exclusively on animals in captivity. Consequently, it is unclear to what extent the unnatural laboratory environment affected time spent sleeping, and thereby the identification and interpretation of informative clues to the functions of sleep. We performed the first electroencephalogram (EEG) recordings of sleep on unrestricted animals in the wild using a recently developed miniaturized EEG recorder, and found that brown-throated three-toed sloths ( 

 Bradypus variegatus 

 ) inhabiting the canopy of a tropical rainforest only sleep 9.63 h d 

 −1 

 , over 6 h less than previously reported in captivity. Although the influence of factors such as the age of the animals studied cannot be ruled out, our results suggest that sleep in the wild may be markedly different from that in captivity. Additional studies of various species are thus needed to determine whether the relationships between sleep duration and various traits identified in captivity are fundamentally different in the wild. Our initial study of sloths demonstrates the feasibility of this endeavour, and thereby opens the door to comparative studies of sleep occurring within the ecological context within which it evolved.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{richter_first_2008,

title = {First application of satellite telemetry to track African straw‐coloured fruit bat migration},

author = {H. V. Richter and G. S. Cumming},

url = {https://zslpublications.onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.2008.00425.x},

doi = {10.1111/j.1469-7998.2008.00425.x},

issn = {0952-8369, 1469-7998},

year  = {2008},

date = {2008-06-01},

urldate = {2025-09-16},

journal = {Journal of Zoology},

volume = {275},

number = {2},

pages = {172\textendash176},

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.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hetem_validation_2007,

title = {Validation of a biotelemetric technique, using ambulatory miniature black globe thermometers, to quantify thermoregulatory behaviour in ungulates},

author = {Robyn S. Hetem and Shane K. Maloney and Andrea Fuller and Leith C. R. Meyer and Duncan Mitchell},

url = {https://onlinelibrary.wiley.com/doi/10.1002/jez.389},

doi = {10.1002/jez.389},

issn = {1932-5223, 1932-5231},

year  = {2007},

date = {2007-06-01},

urldate = {2025-09-16},

journal = {Journal of Experimental Zoology Part A: Ecological Genetics and Physiology},

volume = {307A},

number = {6},

pages = {342\textendash356},

abstract = {Behavioural thermoregulation is an animal’s primary defence against changes in the thermal environment. We aimed to validate a remote technique to quantify the thermal environment behaviourally selected by free-ranging ungulates. First, we demonstrated that the temperature of miniature, 30 mm diameter, black globes (miniglobes) could be converted to standard, 150 mm diameter, black globe temperatures. Miniglobe temperature sensors subsequently were fitted to collars on three free-ranging ungulates, namely blue wildebeest (Connochaetes taurinus), impala (Aepyceros melampus) and horse (Equus caballus). Behavioural observations were reflected in animal miniglobe temperatures which differed from those recorded by an identical miniglobe on a nearby exposed weather station. The wildebeest often selected sites protected from the wind, whereas the impala and the horse sheltered from the sun. Nested analysis of variances revealed that the impala and horse selected significantly less variable environments than those recorded at the weather station (Po0.001) over a 20-min time interval, whereas, the microclimates selected by wildebeest tended to be more variable (P 5 0.08). Correlation of animal miniglobe against weather station miniglobe temperature resulted in regression slopes significantly less than one (Po0.001) for all species studied, implying that, overall, the animals selected cooler microclimate s at high environmental heat loads and/or warmer microclimates at low environmental heat loads. We, therefore, have developed an ambulatory device, which can be attached to free-ranging animals, to remotely quantify thermoregulatory behaviour and selected microclimates. J. Exp. Zool. 307A:342\textendash356, 2007. r 2007 Wiley-Liss, Inc.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{wilson_antennae_2004,

title = {Antennae on transmitters on penguins: balancing energy budgets on the high wire},

author = {Rory P. Wilson and Jan M. Kreye and Klaus Lucke and Heather Urquhart},

url = {https://journals.biologists.com/jeb/article/207/15/2649/14885/Antennae-on-transmitters-on-penguins-balancing},

doi = {10.1242/jeb.01067},

issn = {1477-9145, 0022-0949},

year  = {2004},

date = {2004-07-01},

urldate = {2025-09-16},

journal = {Journal of Experimental Biology},

volume = {207},

number = {15},

pages = {2649\textendash2662},

abstract = {The effect of externally mounted antennae on the energetics of penguins was studied by mounting various antennae on a transducer fixed to a model Magellanic penguin Spheniscus magellanicus to determine drag, run at speeds of up to 2·m·s\textendash1 in a swim canal. For rigid antennae set perpendicular to the water flow, measured drag increased with increasing swim speed. Increasing antenna length (for lengths between 100 and 200·mm) or diameter (for diameters between 1 and 4·mm) resulted in accelerating increased drag as a function of both antenna length and diameter. Where antennae were positioned at acute angles to the water flow, drag was markedly reduced, as was drag at higher speeds in flexible antennae. These results were incorporated in a model on the foraging energetics of free-living Magellanic penguins using data (on swim speeds, intervals between prey encounters, amount ingested per patch and dive durations) derived from previously published work and from a field study conducted on birds from a colony at Punta Norte, Argentina, using data loggers. The field work indicated that free-living birds have a foraging efficiency (net energy gain/net energy loss) of about 2.5. The model predicted that birds equipped with the largest rigid external antennae tested (200·mm × 3·mm diameter), set perpendicular to water flow, increased energy expenditure at normal swim speeds of 1.77·m·s\textendash1 by 79% and at prey capture speeds of 2.25·m·s\textendash1 by 147%, and ultimately led to a foraging efficiency that was about 5 times less than that of unequipped birds. Highly flexible antennae were shown to reduce this effect considerably. Deleterious antenna-induced effects are predicted to be particularly critical in penguins that have to travel fast to capture prey. Possible measures taken by the birds to increase foraging efficiency could include reduced travelling speed and selection of smaller prey types. Suggestions are made as to how antenna-induced drag might be minimized for future studies on marine diving animals.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hegglin_satellite_2004,

title = {Satellite tracking of Bearded Vultures - the project «BEARDED VULTURE ON THE MOVE»},

author = {Daniel Hegglin and Martin Wehrle and Adrian Aebischer},

year  = {2004},

date = {2004-01-01},

keywords = {},

pubstate = {published},

tppubtype = {article}

}