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Müskens, Gerhard J.D.M.

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Müskens
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Gerhard J.D.M.
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Now showing 1 - 10 of 10
  • Data package
    Data from: Towards a new understanding of migration timing: slower spring than autumn migration in geese reflects different decision rules for stopover use and departure
    (2016-02-25) Kölzsch, Andrea; Kruckenberg, Helmut; Glazov, Peter; Müskens, Gerhard J.D.M.; Wikelski, Martin
    According to migration theory and several empirical studies, long-distance migrants are more time-limited during spring migration and should therefore migrate faster in spring than in autumn. Competition for the best breeding sites is supposed to be the main driver, but timing of migration is often also influenced by environmental factors such as food availability and wind conditions. Using GPS tags, we tracked 65 greater white-fronted geese Anser albifrons migrating between western Europe and the Russian Arctic during spring and autumn migration over six different years. Contrary to theory, our birds took considerably longer for spring migration (83 days) than autumn migration (42 days). This difference in duration was mainly determined by time spent at stopovers. Timing and space use during migration suggest that the birds were using different strategies in the two seasons: In spring they spread out in a wide front to acquire extra energy stores in many successive stopover sites (to fuel capital breeding), which is in accordance with previous results that white-fronted geese follow the green wave of spring growth. In autumn they filled up their stores close to the breeding grounds and waited for supportive wind conditions to quickly move to their wintering grounds. Selection for supportive winds was stronger in autumn, when general wind conditions were less favourable than in spring, leading to similar flight speeds in the two seasons. In combination with less stopover time in autumn this led to faster autumn than spring migration. White-fronted geese thus differ from theory that spring migration is faster than autumn migration. We expect our findings of different decision rules between the two migratory seasons to apply more generally, in particular in large birds in which capital breeding is common, and in birds that meet other environmental conditions along their migration route in autumn than in spring.
  • Data package
    Data from: Longer days enable higher diurnal activity for migratory birds [greater white-fronted geese]
    (2021-03-24) Kölzsch, Andrea; Müskens, Gerhard J.D.M.; Moonen, Sander; Kruckenberg, Helmut; Glazov, Peter; Wikelski, Martin
    (1) Seasonal geophysical cycles strongly influence the activity of life on Earth because they affect environmental conditions like temperature, precipitation, and daylength. An increase in daylight availability during summer is especially enhanced when animals migrate along a latitudinal gradient. Yet, the question of how daylength (i.e. daylight availability) influences the activity patterns of long‐distance, latitudinal migrants is still unclear. (2) Here, we ask whether migration provides benefits to long‐distance migrants by enabling them to increase their diurnal movement activities due to an increase in daylight availability. To answer this question, we tested whether four vastly different species of long‐distance migratory birds--two arctic migrants and two mid‐latitude migrants--can capitalise on day length changes by adjusting their daily activity. (3) We quantified the relationship between daily activity (measured using accelerometer data) and day length, and estimated each species' daily activity patterns. In addition, we evaluated the role of day length as an ultimate driver of bird migration. (4) All four species exhibited longer activity periods during days with more daylight hours, showing a strong positive relationship between total daily activity and day length. The slope of this relationship varied between the different species, with activity increasing 1.5‐fold on average when migrating from wintering to breeding grounds. Underlying mechanisms of these relationships reveal two distinct patterns of daily activity. Flying foragers showed increasing activity patterns, i.e. their daytime activities rose uniformly up to solar noon and decreased until dusk, thereby exhibiting a season‐specific activity slope. In contrast, ground foragers showed a constant activity pattern, whereby they immediately increased their activity to a certain level and maintained this level throughout the day. (5) Our study reveals that long days allow birds to prolong their activity and increase their total daily activity. These findings highlight that daylight availability could be an additional ultimate cause of bird migration and act as a selective agent for the evolution of migration.
  • Data package
    Data from: Less is more: on-board lossy compression of accelerometer data increases biologging capacity
    (2020-01-17) Nuijten, Rascha J.M.; Gerrits, Theo; de Vries, Peter P.; Müskens, Gerhard J.D.M.; Nolet, Bart A.
    1. GPS‐tracking devices have been used in combination with a wide range of additional sensors to study animal behaviour, physiology and interaction with their environment. Tri‐axial accelerometers allow researchers to remotely infer the behaviour of individuals, at all places and times. Collection of accelerometer data is relatively cheap in terms of energy usage, but the amount or raw data collected generally requires much storage space and is particularly demanding in terms of energy needed for data transmission. 2. Here we propose compressing the raw ACC data into summary statistics within the tracking device (before transmission) to reduce data size, as a means to overcome limitations in storage and energy capacity. 3. We explored this type of lossy data compression in the accelerometer data of tagged Bewick's swans (Cygnus columbianus bewickii) collected in spring 2017. By using software settings in which bouts of 2 s of both raw ACC data and summary statistics were collected in parallel but with different bout intervals to keep total data size comparable, we created the opportunity for a direct comparison of time budgets derived by the two data collection methods. 4. We found that the data compression in our case yielded a 6 time reduction in data size per bout, and concurrent, similar decreases in storage and energy use of the device. We show that with the same accuracy of the behavioural classification, the freed memory and energy of the device can be used to increase the monitoring effort, resulting in a more detailed representation of the individuals’ time budget. Rare and/or short behaviours such as daily roost flights, were picked up significantly more when collecting summary statistics instead of raw ACC data (but note differences in sampling rate). Such level of detail can be of essential importance, for instance to make a reliable estimate of the energy budgets of individuals. 5. In conclusion, we argue that this type of lossy data compression can be a well‐considered choice in study situations where limitations in energy and storage space of the device pose a problem. Ultimately these developments can allow for long‐term and nearly continuous remote‐monitoring of the behaviour of free‐ranging animals.
  • Data package
    Data from: Wild goose chase: geese flee high and far, and with aftereffects from New Year’s fireworks
    (2022-11-28) Kölzsch, Andrea; Lameris, Thomas K.; Müskens, Gerhard J.D.M.; Schreven, Kees H.T.; Buitendijk, Nelleke H.; Kruckenberg, Helmut; Moonen, Sander; Heinicke, Thomas; Cao, Lei; Madsen, Jesper; Wikelski, Martin; Nolet, Bart A.
    In the present Anthropocene, wild animals are globally affected by human activity. Consumer fireworks during New Year (NY) are widely distributed in W-Europe and cause strong disturbances that are known to incur stress responses in animals. We analyzed GPS tracks of 347 wild migratory geese of four species during eight NYs quantifying the effects of fireworks on individuals. We show that, in parallel with particulate matter increases, during the night of NY geese flew on average 5–16 km further and 40–150 m higher, and more often shifted to new roost sites than on previous nights. This was also true during the 2020–2021 fireworks ban, despite fireworks activity being reduced. Likely to compensate for extra flight costs, most geese moved less and increased their feeding activity in the following days. Our findings indicate negative effects of NY fireworks on wild birds beyond the previously demonstrated immediate response.
  • Data package
    Data from: A periodic Markov model to formalise animal migration on a network [white-fronted goose data]
    (2018-06-13) Kruckenberg, Helmut; Müskens, Gerhard J.D.M.; Ebbinge, Barwolt S.
    NOTE: A portion of these same individuals and data are also published with doi 10.5441/001/1.31c2v92f. Regular, long-distance migrations of thousands of animal species have consequences for the ecosystems that they visit, modifying trophic interactions and transporting many non-pathogenic and pathogenic organisms. The spatial structure and dynamic properties of animal migrations and population flyways largely determine those trophic and transport effects, but are yet poorly studied. As a basis, we propose a periodic Markov model on the spatial migration network of breeding, stopover and wintering sites to formally describe the process of animal migration on the population level. From seasonally changing transition rates we derived stable, seasonal densities of animals at the network nodes. We parametrized the model with high-quality GPS and satellite telemetry tracks of white storks (Ciconia ciconia) and greater white-fronted geese (Anser a. albifrons). Topological and network flow properties of the two derived networks conform to migration properties like seasonally changing connectivity and shared, directed movement. Thus, the model realistically describes the migration movement of complete populations and can become an important tool to study the effects of climate and habitat change and pathogen spread on migratory animals. Furthermore, the property of periodically changing transition rates makes it a new type of complex model and we need to understand its dynamic properties.
  • Data package
    Data from: Scaring waterfowl as a management tool: how much more do geese forage after disturbance?
    (2016-05-20) Kölzsch, Andrea; Müskens, Gerhard J.D.M.; Nolet, Bart A.; Wikelski, Martin
    (1) With increasing numbers of many herbivorous waterfowl species, often foraging on farmland, the conflict with agriculture has intensified. One popular management tool is to scare birds off the land, often in association with shooting. However, the energy costs of flying are considerably higher than those of resting. Therefore, when birds fly off after a disturbance, they use extra energy that subsequently needs to be compensated. (2) We used the white-fronted goose Anser albifrons, the most common (grass-eating) species wintering in western Europe, as a model species. We measured flight durations by high-frequency accelerometer recordings over 2 × 24 h in 9 focal geese that were only incidentally disturbed. We also made direct observations on these days to determine whether the flight durations were reliably recorded. Using both a simple and a more realistic model of the energy balance, we calculated the extra grass consumption resulting from additional intentional disturbances. (3) On average, the geese flew daily 2 × 323 s (from and to their roosting sites at 3200 m), and furthermore took to the air 5.3 times during a day (and 1.9 times a night). Multiplied with the average flight durations of 195 s, this gives a total flying time of almost 0.6 h day-1 and a total foraging time of 7.4 h day-1. The extra foraging time needed to compensate for additional intentional disturbances strongly depends on the frequency of such disturbances and the following flight duration. If, for example, flights when intentionally disturbed are twice as long (2 × 195 s), the extra foraging time will be 3.7% day-1 (2.3–3.2% day-1 in the more realistic model) for each intentional disturbance, and the geese will no longer be able to cover their energy requirements when intentionally disturbed six times per day. (4) Synthesis and applications. Recent experiments suggest that geese have to be scared frequently in order to reduce goose visitation to particular fields. With an intentional disturbance rate e.g. of five times a day, the birds’ compensation for the increased energy expenditure will lead to a higher overall consumption of grass of 11.5–16 % day-1. Accommodation schemes have to take such increases in total grass consumption into account when deciding on the refuge areas to be set aside.
  • Data package
    Data from: Flyway connectivity and exchange primarily driven by moult migration in geese [Pannonic population]
    (2019-02-06) Müskens, Gerhard J.D.M.; Szinai, Péter; Sapi, Tamas; Kölzsch, Andrea; Wikelski, Martin; Nolet, Bart A.
    Background: For the conservation and management of migratory species that strongly decrease or increase due to anthropological impacts, a clear delineation of populations and quantification of possible mixing (migratory connectivity) is crucial. Usually, population exchange in migratory species is only studied in breeding or wintering sites, but we considered the whole annual cycle in order to determine important stages and sites for population mixing in an Arctic migrant. Methods: We used 91 high resolution GPS tracks of Western Palearctic greater white-fronted geese (Anser A. albifrons) from the North Sea and Pannonic populations to extract details of where and when populations overlapped and exchange was possible. Overlap areas were calculated as dynamic Brownian bridges of stopover, nest and moulting sites. Results: Utilisation areas of the two populations overlapped only somewhat during spring and autumn migration stopovers, but much during moult. During this stage, non-breeders and failed breeders of the North Sea population intermixed with geese from the Pannonic population in the Pyasina delta on Taimyr peninsula. The timing of use of overlap areas was highly consistent between populations, making exchange possible. Two of our tracked geese switched from the North Sea population flyway to the Pannonic flyway during moult on Taimyr peninsula or early during the subsequent autumn migration. Because we could follow one of them during the next year, where it stayed in the Pannonic flyway, we suggest that the exchange was long-term or permanent. Conclusions: We have identified long-distance moult migration of failed or non-breeders as a key phenomenon creating overlap between two flyway populations of geese. This supports the notion of previously suggested population exchange and migratory connectivity, but outside of classically suggested wintering or breeding sites. Our results call for consideration of moult migration and population exchange in conservation and management of our greater white-fronted geese as well as other waterfowl populations.
  • Data package
    Data from: Study "Eurasian wigeon (Mareca penelope) Netherlands Lithuania 2018-2019"
    (2021-12-16) van Toor, Mariëlle L.; Kharitonov, Sergey; Švažas, Saulius; Dagys, Mindaugas; Kleyheeg, Eric; Müskens, Gerhard J.D.M.; Ottosson, Ulf; Žydelis, Ramunas; Waldenström, Jonas
    Background: The timing of migration for herbivorous migratory birds is thought to coincide with spring phenology as emerging vegetation supplies them with the resources to fuel migration, and, in species with a capital breeding strategy also provides individuals with energy for use on the breeding grounds. Individuals with very long migration distances might however have to trade off between utilising optimal conditions en route and reaching the breeding grounds early, potentially leading to them overtaking spring on the way. Here, we investigate whether migration distance affects how closely individually tracked Eurasian wigeons follow spring phenology during spring migration. Methods: We captured wigeons in the Netherlands and Lithuania and tracked them throughout spring migration to identify staging sites and timing of arrival. Using temperature-derived indicators of spring phenology, we investigated how maximum longitude reached and migration distance affected how closely wigeons followed spring. We further estimated the impact of tagging on wigeon migration by comparing spring migratory timing between tracked individuals and ring recovery data sets. Results: Wigeons migrated to locations between 300 and 4000 km from the capture site, and migrated up to 1000 km in a single day. We found that wigeons migrating to more north-easterly locations followed spring phenology more closely, and increasingly so the greater distance they had covered during migration. Yet we also found that despite tags equalling only around 2% of individual’s body mass, individuals were on average 11–12 days slower than ring-marked individuals from the same general population. Discussion: Overall, our results suggest that migratory strategy can vary dependent on migration distance within species, and even within the same migratory corridor. Individual decisions thus depend not only on environmental cues, but potentially also trade-offs made during later life-history stages.
  • Data package
    Data from: Flyway connectivity and exchange primarily driven by moult migration in geese [North Sea population]
    (2019-02-06) Kölzsch, Andrea; Müskens, Gerhard J.D.M.; Moonen, Sander; Kruckenberg, Helmut; Glazov, Peter; Wikelski, Martin
    Background: For the conservation and management of migratory species that strongly decrease or increase due to anthropological impacts, a clear delineation of populations and quantification of possible mixing (migratory connectivity) is crucial. Usually, population exchange in migratory species is only studied in breeding or wintering sites, but we considered the whole annual cycle in order to determine important stages and sites for population mixing in an Arctic migrant. Methods: We used 91 high resolution GPS tracks of Western Palearctic greater white-fronted geese (Anser A. albifrons) from the North Sea and Pannonic populations to extract details of where and when populations overlapped and exchange was possible. Overlap areas were calculated as dynamic Brownian bridges of stopover, nest and moulting sites. Results: Utilisation areas of the two populations overlapped only somewhat during spring and autumn migration stopovers, but much during moult. During this stage, non-breeders and failed breeders of the North Sea population intermixed with geese from the Pannonic population in the Pyasina delta on Taimyr peninsula. The timing of use of overlap areas was highly consistent between populations, making exchange possible. Two of our tracked geese switched from the North Sea population flyway to the Pannonic flyway during moult on Taimyr peninsula or early during the subsequent autumn migration. Because we could follow one of them during the next year, where it stayed in the Pannonic flyway, we suggest that the exchange was long-term or permanent. Conclusions: We have identified long-distance moult migration of failed or non-breeders as a key phenomenon creating overlap between two flyway populations of geese. This supports the notion of previously suggested population exchange and migratory connectivity, but outside of classically suggested wintering or breeding sites. Our results call for consideration of moult migration and population exchange in conservation and management of our greater white-fronted geese as well as other waterfowl populations.
  • Data package
    Data from: Goose parents lead migration V
    (2020-01-22) Kölzsch, Andrea; Müskens, Gerhard J.D.M.; Glazov, Peter; Kruckenberg, Helmut; Wikelski, Martin
    Many migratory animals travel in large social groups. Large, avian migrants that fly in V‐formations were proposed do so for energy saving by the use of up‐wash by following individuals and regularly change leadership. As groups have been rather homogeneous in previous work, we aimed to explore leadership and its flight mechanics consequences in an extremely heterogeneous case of social migration, namely in spring migration of goose families. In families the experience of group members differs strongly and inclusive fitness may be important. We successfully collected overlapping spring migration tracking data of a complete family of greater white‐fronted geese (Anser a. albifrons) and extracted leadership, flapping frequency and wind conditions in flight. Our data revealed V‐formations where one parent was flying in front at all times. Although the father led the family group most of the time, he did not flap at higher frequency while doing so. In contrast, the mother flapped faster when leading, possibly because she experienced less supportive wind conditions than when the father led. We argue that in heterogeneous, social groups leadership might be fixed and not costly if supportive environmental conditions like wind can be used.