Sensor:Acceleration
Acceleration
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Acceleration
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acceleration
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- Data packageData from: The effect of feeding time on dispersal of Virola seeds by toucans determined from GPS tracking and accelerometers(2016-01-12) Kays, Roland; Jansen, Patrick A.; Knecht, Elise M.H.; Vohwinkel, Reinhard; Wikelski, MartinSeed dispersal is critical to understanding forest dynamics but is hard to study because tracking seeds is difficult. Even for the best-studied dispersal system of the Neotropics, Virola nobilis, the dispersal kernel remains unknown. We combined high-resolution GPS/3D-acceleration bird tracking, seed-retention experiments, and field observations to quantify dispersal of V. nobilis by their principal dispersers, Ramphastos toucans. We inferred feeding events from movement data, and then estimated spatiotemporally explicit seed-dispersal kernels. Wild toucans moved an average of 1.8 km d^-1 with two distinct activity peaks. Seed retention time in captive toucans averaged 25.5 min (range 4-98 min). Estimated seed dispersal distance averaged 144 +/- 147 m, with a 56% likelihood of dispersal >100 m, two times further than the behaviour-naive estimate from the same data. Dispersal was furthest for seeds ingested in the morning, and increased with seed retention time, but only up to 60 min after feeding. Our study supports the long-standing hypothesis that toucans are excellent dispersers of Virola seeds. To maximize seed dispersal distances trees should ripen fruit in the morning when birds move the most, and produce fruits with gut-processing times around 60 min. Our study demonstrates how new tracking technology can yield nuanced seed dispersal kernels for animals that cannot be directly observed.
- Data packageData from: Uncovering behavioural states from animal activity and site fidelity patterns(2017-10-23) Mahoney, Peter J.; Ebinger, Michael; Jaeger, Michael; Shivik, John A.; Young, Julie K.(1) Space use by animals has important implications for individual fitness. However, resource requirements often vary throughout the course of a lifetime and are a reflection of the demands associated with daily tasks or specific life-history phases, from food acquisition to reproduction, and emphasize the need to classify resource selection relative to specific behavioural states. Site fidelity is often indicative of behaviours important for individual maintenance (e.g. foraging), species' life history (e.g. seasonal site selection), social communication (e.g. scent-marking) and species interactions (e.g. predation, competition). Thus, resolving site fidelity patterns associated with key behaviours is essential to accurately quantify behavioural-dependent resource needs and the fitness consequences of space use. (2) We propose a novel method for identifying site fidelity patterns in animal location data using a convex hull clustering program called R Animal Site Fidelity (rASF). We also provide a means of integrating activity as a measure of behavioural state. We demonstrate the utility of the approach in identifying cougar (Puma concolor) predation events, coyote (Canis latrans) den and rendezvous sites, and coyote territorial boundaries. (3) We parameterized rASF based on site fidelity characteristics that best characterized the clustering behaviour of interest and estimated behavioural state from either dual-axial accelerometer data or movement trajectory statistics. When behaviour was used in conjunction with cluster-specific metrics (duration, proportion of diurnal fixes and landscape composition), we could accurately predict prey species associated with cougar kills and differentiate pup-rearing from scent-marking sites in coyotes. (4) Site fidelity patterns and activities associated with animal revisitation will be key to identifying the behavioural motivations behind observed patterns of space use. Our approach provides an efficient, rigorous and repeatable means of identifying site fidelity patterns associated with specific behavioural states without the need for direct observations, which are often impossible to collect at large spatial scales and in dense habitat. As such, this framework has significant potential to inform theory in behavioural ecology while providing managers with better resolution on appropriate management targets associated with key aspects of a species' life history.
- Data packageData from: Feeling the heat: elevated temperature affects male display activity of a lekking grassland bird(2019-09-05) Silva, João Paulo; Gudka, Mishal; Abad-Gómez, José Maria; Santos, Carlos DavidMost species-climate models relate range margins to long-term mean climate but lack mechanistic understanding of the ecological or demographic processes underlying the climate response. We examined the case of a climatically limited edge-of-range population of a medium-sized grassland bird, for which climate responses may involve a behavioural trade-off between temperature stress and reproduction. We hypothesised that temperature will be a limiting factor for the conspicuous, male snort-call display behaviour, and high temperatures would reduce the display activity of male birds. Using remote tracking technology with tri-axial accelerometers we classified and studied the display behaviour of 17 free-ranging male little bustards, Tetrax tetrax, at 5 sites in the Iberian Peninsula. Display behaviour was related to temperature using two classes of Generalized Additive Mixed Models (GAMMs) at different temporal resolutions. GAMMs showed that temperature, time of the day and Julian date explained variation in display behaviour within the day, with birds snort-calling significantly less during higher temperatures. We also showed that variation in daily snort-call activity was related to average daytime temperatures, with our model predicting an average decrease in daytime snort-call display activity of up to 10.4% for the temperature increases projected by 2100 in this region due to global warming. For lekking birds and mammals undertaking energetically-costly displays in a warming climate, reduced display behaviour could impact inter- and intra-sex mating behaviour interactions through sexual selection and mate choice mechanisms, with possible consequences on mating and reproductive success. The study provides a reproducible example for how accelerometer data can be used to answer research questions with important conservation inferences related to the impacts of climate change on a range of taxonomic groups.
- Data packageData from: Dynamic body acceleration increases by 20% during flight ontogeny of greylag geese (Anser anser)(2019-11-15) Gatt, Marie Claire; Quetting, Michael; Cheng, Yachang; Wikelski, MartinDespite our knowledge of the biophysical and behavioural changes during flight ontogeny in juvenile birds, little is known about the changes in the mechanical aspects of energy expenditure during early flight development, particularly in migratory species. Here, we investigate in a unique experimental setup how energy expended during flights changes over time beginning with early ontogeny. We calculate overall dynamic body acceleration (ODBA) as a proxy for energy expenditure in a group of hand raised Greylag Geese (Anser anser) trained to fly behind a microlight aircraft. We propose two potential hypotheses; energy expenditure either increases with increasing physiological suitability (the ‘physical development hypothesis’), or decreases as a result of behavioural improvements mitigating flight costs (the ‘behavioural development hypothesis’). There was a significant temporal increase of flight duration and ODBA over time, supporting the ‘physical development hypothesis’. This suggests that early on in flight ontogeny behavioural development leading to flight efficiency plays a weaker role in shaping ODBA changes than the increased physical ability to expend energy in flight. We discuss these findings and the implications of flight development on the life history of migratory species.
- Data packageData from: Moulting sites of Latvian whooper swan Cygnus cygnus cygnets fitted with GPS-GSM transmitters(2019-12-31) Boiko, Dmitrijs; Wikelski, Martin; Fiedler, WolfgangPrevious studies on Whooper Swan Cygnus cygnus cygnets hatched in Latvia have shown that c. 99% leave the country each year to moult elsewhere in their 2nd to 6th calendar years. To reveal the exact moulting sites, in 2016 ten cygnets were fitted with 91g solar-powered neck-collar-mounted GPS-GSM loggers. Moulting sites were recorded for four individuals in their 2nd calendar year, and for two of these birds in their 3rd calendar year; four birds in total. All of these moulted at sites in Russia; one was in the Republic of Karelia and three were in the Arkhangelsk Region. The mean average straight-line distance between the hatching and moulting sites was 1,451 km (range = 1,038–2,524 km). Although the data were less comprehensive, another tracked swan probably moulted in the western part of the White Sea in the Republic of Karelia. The conservation of these moulting sites is essential for the Latvian Whooper Swans to thrive.
- Data packageData from: Landscape-dependent time versus energy optimisations in pelicans migrating through a large ecological barrier(2019-08-08) Efrat, Ron; Hatzofe, Ohad; Nathan, Ran1. During migration, birds are often forced to cross ecological barriers, facing challenges due to scarcity of resources and suitable habitats. While crossing such barriers, birds are expected to adjust their behaviour to reduce time, energy expenditure and associated risks. 2. We studied the crossing of the Sahara Desert by the Great White Pelican (Pelecanus onocrotalus), a large wetland‐specialist. We focused on decisions made by migrating pelicans along different parts of the southbound autumn migration, their response to local environmental conditions, and the implications for time and energy optimisations. We compared the observed pelicans' migration routes with simulated “direct‐pass” (shortest, mostly across the desert) and “corridor‐pass” (along the Nile River) routes, and used GPS, body acceleration and atmospheric modelling to compare flight behaviour along the Nile River versus the desert. 3. The observed route was significantly shorter and faster than the simulated corridor‐pass route and not significantly different from the simulated direct‐pass one. Daily flights over the desert were longer than along the Nile River, with flying time extending to late hours of the day despite unfavourable atmospheric conditions for soaring‐gliding flight. Moreover, the pelicans behavioural response to atmospheric conditions changed according to the landscape over which they flew. Overall, the pelicans showed stronger behavioural adjustments to atmospheric conditions over the desert than along the Nile River. 4. Our findings suggest that migrating pelicans primarily acted as time minimisers while crossing the Sahara Desert, whereas energetic optimisation was only considered when it did not substantially compromise time optimisation. The pelicans took the almost shortest possible route, only following the Nile River along its south‐oriented parts, and frequently staged overnight in the desert far from water, despite being large, wet‐habitat specialists. Correspondingly, their behavioural response to atmospheric conditions changed according to the landscape over which they were flying, switching between time (over the desert) and energy (over the Nile River) optimisation strategies. Our results suggest that the interaction between landscape and atmospheric conditions depict a flexible, yet primarily time‐dominated, migration optimisation strategy.
- Data packageData from: Overall dynamic body acceleration in straw-colored fruit bats increases in headwinds but not with airspeed(2019-05-21) Scharf, Anne K.; Fahr, Jakob; Abedi-Lartey, Michael; Safi, Kamran; Dechmann, Dina K.N.; Wikelski, Martin; O'Mara, M. TeagueAtmospheric conditions impact how animals use the aerosphere, and birds and bats should modify their flight to minimise energetic expenditure relative to changing wind conditions. To investigate how free-ranging straw-colored fruit bats (Eidolon helvum) fly with changing wind support, we use data collected from bats fit with GPS loggers and an integrated triaxial accelerometer and measure flight speeds, wingbeat frequency, and overall dynamic body acceleration (ODBA) as an estimate for energetic expenditure. We predicted that if ODBA reflects energetic expenditure, then we should find a curvilinear relationship between ODBA and airspeed consistent with aerodynamic theory. We expected that bats would lower their airspeed with tailwind support and that ODBA will decrease with increasing tailwinds and increase with wingbeat frequency. We found that wingbeat frequency has the strongest positive relationship with ODBA. There was a small, but negative, relationship between airspeed and ODBA, and bats decreased ODBA with increasing tailwind. Bats flew at ground speeds of 9.6 ± 2.4 ms-1 (mean ± sd, range: 4.3 to 23.9 ms-1) and airspeeds of 10.2 ± 2.5 ms-1, and did not modify their wingbeat frequency with speed. Free-ranging straw-colored fruit bats therefore exerted more total ODBA in headwinds but not when they changed their airspeed. It is possible that the flexibility in wingbeat kinematics may make flight of free-ranging bats less costly than currently predicted or alternatively that the combination of ODBA and airspeed at our scales of measurement does not reflect this relationship in straw-colored fruit bats. Further work is needed to understand the full potential of free-ranging bat flight and how well bio-logging techniques reflect the costs of bat flight.
- Data packageData from: Stink or swim: techniques to meet the challenges for the study and conservation of small critters that hide, swim or climb and may otherwise make themselves unpleasant.(2015-05-25) Kays, Roland; Hirsch, Ben T.The study of musteloids requires different perspectives and techniques than those needed for most mammals. Musteloids are generally small yet travel long distances and many live or forage underground or under water, limiting the use of telemetry and direct observation. Some are arboreal and nocturnal, facilitating telemetry but limiting observation, trapping, and many non-invasive techniques. Large sexual size dimorphism arguably doubles sample sizes for many research questions. Many musteloids defend themselves by expelling noxious chemicals. This obscure group does not attract funding, even when endangered, further reducing rate of knowledge gain. Nonetheless, passive and active radio frequency identification tags, magnetic-inductance tracking, accelerometers, mini-biologgers and some GPS tags are tiny enough for use with small musteloids. Environmental DNA can document presence of animals rarely seen. These technologies, coupled with creative research design that is well-grounded on the scientific method, form a multi-dimensional approach for advancing our understanding of these charismatic minifauna.
- Data packageData from: The challenges of the first migration: movement and behavior of juvenile versus adult white storks with insights regarding juvenile mortality(2016-04-12) Rotics, Shay; Kaatz, Michael; Resheff, Yehezkel S.; Turjeman, Sondra Feldman; Zurell, Damaris; Sapir, Nir; Eggers, Ute; Flack, Andrea; Fiedler, Wolfgang; Jeltsch, Florian; Wikelski, Martin; Nathan, Ran(1) Migration conveys an immense challenge especially for juvenile birds coping with enduring and risky journeys shortly after fledging. Accordingly, juveniles exhibit considerably lower survival rates compared to adults, particularly during migration. Also, juvenile white storks (Ciconia ciconia), which are known to rely on adults during their first fall migration, presumably for navigational purposes, display much lower annual survival than adults. (2) Using detailed GPS and body acceleration data, we examined the patterns and potential causes of age-related differences in fall migration properties of white storks by comparing first-year juveniles and adults. We compared juvenile and adult parameters of movement, behavior and energy expenditure (estimated from overall dynamic body acceleration, ODBA) and placed this in the context of the juveniles’ lower survival rate. (3) Juveniles used flapping flight versus soaring flight 23% more than adults and were estimated to expend 14% more energy during flight. Juveniles did not compensate for increased flight costs by increased refueling or resting during migration. When juveniles and adults migrated together in the same flock, the juvenile flew mostly behind the adult and was left behind when they separated. Juveniles showed greater improvement in flight efficiency throughout migration compared to adults which appears crucial because juveniles exhibiting higher flight costs suffered increased mortality. (4) Our findings demonstrate the conflict between the juveniles’ inferior flight skills and their urge to keep up with mixed adult-juvenile flocks. We suggest that increased flight costs are an important proximate cause of juvenile mortality in white storks and likely in other soaring migrants, and that natural selection is operating on juvenile variation in flight efficiency.
- Data packageData from: Costs of migratory decisions: a comparison across eight white stork populations(2015-06-13) Flack, Andrea; Fiedler, Wolfgang; Blas, Julio; Pokrovsky, Ivan; Mitropolsky, B.; Kaatz, Michael; Aghababyan, Karen; Khachatryan, A.; Fakriadis, Ioannis; Makrigianni, Eleni; Jerzak, Leszek; Shamin, M.; Shamina, C.; Azafzaf, H.; Mokotjomela, Thabiso M.; Feltrup-Azafzaf, Claudia; Wikelski, MartinAnnual migratory movements can range from a few tens to thousands of kilometers, creating unique energetic requirements for each specific species and journey. Even within the same species, migration costs can vary largely because of flexible, opportunistic life history strategies. We uncover the large extent of variation in the lifetime migratory decisions of young white storks originating from eight populations. Not only did juvenile storks differ in their geographically distinct wintering locations, their diverse migration patterns also affected the amount of energy individuals invested for locomotion during the first months of their life. Overwintering in areas with higher human population reduced the stork’s overall energy expenditure because of shorter daily foraging trips, closer wintering grounds, or a complete suppression of migration. Because migrants can change ecological processes in several distinct communities simultaneously, understanding their life history decisions helps not only to protect migratory species but also to conserve stable ecosystems.