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Map showing spring migratory route of Russian breeding barnacle geese with distances between staging sites and observation points. Dark grey shaded areas indicate wintering/staging grounds in the Wadden Sea and Baltic, and breeding grounds in Russia.
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1. Since the early 1990s, an increasing proportion of barnacle geese, Branta leucopsis, bound for breeding sites in the Russian Arctic delay their departure from the wintering quarters in the Wadden Sea by 4 weeks. These late-migrating geese skip spring stopover sites in the Baltic traditionally used by the entire population. 2. Individual geese fr...
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Context 1
... birds (Black et al . 2007). After pre-migratory fattening in the Wadden Sea, the geese migrate via stopovers in the Baltic, most notably in western Estonia and on the Swedish Island of Gotland (Ebbinge, Van Biezen & Van der Voet 1991; Leito, Renno & Kuresoo 1991), and stopovers in the White Sea to their breeding grounds on the Barents Sea coast (Fig. 1). Traditional breeding areas of this population were restricted mainly to the islands of Novaya Zemlya and Vaygach in the eastern Barents Sea. Through expansion since the 1980s, arctic breeding occurs now down to the eastern White Sea coast 650 km westwards ( Ganter et al . 1999). Barnacle geese feed predominantly on coastal salt ...
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... by-passed or not and whether the Dvina River or Kanin Peninsula is chosen as next fuelling site. The costs of by-passing the Baltic are expressed as additional fuel load and as percentage extra fuel needed relative to not by-passing the Baltic assuming that the geese leave for their next target site as soon as fuel loads permit to fly there. See Fig. 1 schedules and fitness of arctic geese have been demonstrated by Bauer et al. (2008b) for the pink-footed goose. This species has discovered a new staging site in mid-Norway and increas- ingly use it in response to a warming climate (Fox et al. 2005). Furthermore, Pistorius, Follestad & Taylor (2006) suggested that increasingly warmer ...
Context 3
... by the inaccessibility of sites further north along the route (which are still snow bound at that time), the geese con- centrate on pre-migratory sites. It is important to note that most of the Wadden Sea sites where barnacle geese now- adays concentrate in spring have only come in use since the early 1990s, for example the Dollard estuary (Fig. 1) at the Dutch-German border (Aerts, Esselink & Helder 1996). In other words, the new delayed strategy involves exploitation of new spring staging resources in the Wadden Sea as well as a change in ...
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Citations
... Most of the individuals in our study were birds with no preference to observe a partner with one of the eyes. This may be due to the highly competitive behaviour in the geese' flocks (Prop 2004) and high levels of threat from predation (Eichhorn et al. 2009) or hunting (Mooij et al. 1999). Previous research on Barnacle Geese and Greater White-fronted Geese has also shown that high levels of threat prevent the manifestation of visual lateralisation at the population level in geese (Zaynagutdinova et al. 2020b). ...
Sensory lateralisation, defined as the separation of functions for processing information from the sensory organs between the hemispheres of the brain, is a variable characteristic of the nervous system influenced by external factors. The plasticity of lateralisation is an important factor influencing the assessment of lateralisation on individual and population levels. We tested the influence of sunlight and time of the day on the visual lateralisation of Greater White-fronted Geese Anser albifrons when following their partners. Most of the individuals showed no preference to observe a partner with one of their eyes. Among the lateralised birds, a significant prevalence of right-eyed individuals was revealed. The highest proportion of lateralised individuals was observed in cloudy conditions. Direct sunlight, particularly in the morning, interfered with the emergence of visual lateralisation. Thus, the effect of sunlight and time of the day on lateralisation in birds should be taken into account when evaluating lateralisation in field observations and experiments.
... If the success of the alternative foraging strategy is maintained in this falcon population in the long term, as seems to be the case in recent years, it may cause divergent selection. For example, population growth and climatic changes initiated trade-offs in barnacle geese that led to the development of new life-history strategies (Eichhorn et al. 2009) and to subsequent genetic divergence among breeding areas, suggesting that behavioral changes may drive rapid evolution (Jonker et al. 2013). The emergence of new foraging and breeding strategies in this Eleonora's falcon population may ultimately promote advances in the timing of breeding and the maintenance of color polymorphism in this species through trophic selection if the strategy remains associated with the morph. ...
Intraspecific phenotypic variability is key to respond to environmental changes and anomalies. However, documenting the emergence of behavioral diversification in natural populations has remained elusive due to the difficulty of observing such phenomenon at the right time and place. Here, we investigated how the emergence of a new trophic strategy in a population subjected to high fluctuations in the availability of its main trophic resource (migrating songbirds) affected the breeding performance, population structure, and population fitness of a specialized color polymorphic predator, the Eleonora’s falcon from the Canary Islands. Using long-term data (2007-2022), we found that the exploitation of an alternative prey (a local petrel species) was associated with the growth of a previously residual falcon colony. Pairs in this colony laid earlier and raised more fledglings than in the other established colonies. The specialization on petrels increased over time, independently of annual fluctuations in prey availability. Importantly, however, the positive effect of petrel consumption on productivity was stronger in years with lower food availability. This trophic diversification was further associated with the genetically-determined color morph, with dark individuals preying more frequently on petrels than pale ones, which might promote the long-term maintenance of genotypic and phenotypic diversity. We empirically demonstrate how the emergence of an alternative trophic strategy can buffer populations against harsh environmental fluctuations by stabilizing their productivity.
... The migratory strategies of many animal species are rapidly changing due to anthropogenic influences, such as land transformation and climate change (Sutherland 1998, Maclean et al. 2008, Visser et al. 2009, Cox 2010. These changes are multifaceted and can encompass modifications in the timing of migration departure and arrival (Jenni and Kéry 2003, Cotton 2003, Gordo and Sanz 2006, the shortening or diversion of migratory routes (Sutherland 1998, Eichhorn et al. 2009), or the complete disruption of migration and the transition towards residency (Pulido and Berthold 2010, Plummer et al. 2015, Satterfield et al. 2015. Ultimately, these adjustments can influence ecological and evolutionary processes at multiple scales, from the individual to the ecosystem (Nathan et al. 2008, Dingle 2014. ...
Alternative migratory strategies can coexist within animal populations and species. Anthropogenic impacts can shift the fitness balance between these strategies leading to changes in migratory behaviors. Yet some of the mechanisms that drive such changes remain poorly understood. Here we investigate the phenotypic differences, and the energetic, behavioral, and fitness trade‐offs associated with four different movement strategies (long‐distance and short‐distance migration, and regional and local residency) in a population of white storks (Ciconia ciconia) that has shifted its migratory behavior over the last decades, from fully long‐distance migration toward year‐round residency. To do this, we tracked 75 adult storks fitted with GPS/GSM loggers with tri‐axial acceleration sensors over 5 years, and estimated individual displacement, behavior, and overall dynamic body acceleration, a proxy for activity‐related energy expenditure. Additionally, we monitored nesting colonies to assess individual survival and breeding success. We found that long‐distance migrants traveled thousands of kilometers more throughout the year, spent more energy, and >10% less time resting compared with short‐distance migrants and residents. Long‐distance migrants also spent on average more energy per unit of time while foraging, and less energy per unit of time while soaring. Migratory individuals also occupied their nests later than resident ones, later occupation led to later laying dates and a lower number of fledglings. However, we did not find significant differences in survival probability. Finally, we found phenotypic differences in the migratory probability, as smaller sized individuals were more likely to migrate, and they might be incurring higher energetic and fitness costs than larger ones. Our results shed light on the shifting migratory strategies in a partially migratory population and highlight the nuances of anthropogenic impacts on species behavior, fitness, and evolutionary dynamics.
... Land-use changes may also affect the suitability of stopover and staging sites (Guillemain et al. 2015b), causing birds to stay longer where more resources are available. Many factors may impact migration timing, including precipitation (O'Neal et al. 2018), wind (O'Neal et al. 2018, Xu and Si 2019, Haest et al. 2019, intraspecific competition (Eichhorn et al. 2009, Stirnemann et al. 2012, predation pressure (Jonker et al. 2012), and human disturbance (Väänänen 2001), which can complicate identifying and understanding changes in fall migration phenology. Moreover, unlike spring, where migration timing is driven by a desire to migrate quickly and arrive on the breeding grounds early, fall migration is more flexible (Yohannes et al. 2009, Karlsson et al. 2012, which may make shifts in fall migration timing more difficult to decipher than in the spring. ...
Worldwide, migratory phenology and movement of many bird species is shifting in response to anthropogenic climate and habitat changes. However, due to variation among species and a shortage of analyses, changes in waterfowl migration, particularly in the fall, are not well understood. Fall migration phenology and movement patterns dictate waterfowl hunting success and satisfaction, with cascading implications on economies and support for habitat management and securement. Using 60 years of band recovery data for waterfowl banded in the Canadian Prairie Pothole Region (PPR), we evaluated whether fall migration timing and/or distribution changed in Mallard (Anas platyrhynchos), Northern Pintail (A. acuta), and Blue-winged Teal (Spatula discors) between 1960 and 2019. We found that in the Midcontinent Flyways, Mallards and Blue-winged Teal migrated faster in more recent time periods, whereas Northern Pintail began fall migration earlier. In the Pacific Flyway, Mallards began fall migration earlier. Both Mallards and Northern Pintails showed evidence of short-stopping in the Midcontinent Flyways. Indeed, the Mallard and Northern Pintail distribution of band recovery data shifted 180 and 226 km north, respectively, from 1960 to 2019. Conversely, Blue-winged Teal recovery distributions were consistent across years. Mallards and Northern Pintails also exhibited an increased proportion of band recoveries in the Pacific Flyway in recent decades. We provide clear evidence that the timing and routes of fall migration have shifted over the past 6 decades, but these phenological and spatial shifts differ among species. We suggest that using community-science data collected by hunters themselves to explain one of the group’s major concerns (changes in duck abundance at traditional hunting grounds), within the environmental lens of climate change, may help lead to further engagement and two-way dialogue to support effective waterfowl management for these culturally and ecologically important species.
... Overall, differences in the extent of climatic change along migratory routes, as well as at wintering, stopover and breeding areas [11][12][13], increase the chance of phenological mismatch (i.e. when interacting species change the timing of regularly repeated life cycle phases at different rates), thus influencing the interactions among cooccurring species including their food sources, predators, and competitors [14,15]. Indeed, migrations involve the simultaneous movement of multiple species at once connecting separated and diverse communities whose migratory routes often converge in space and time [16], resulting in direct and indirect ecological interactions such as predation, social interactions and competition for resources [17][18][19][20]. ...
Migratory species are changing their timing of departure from wintering areas and arrival to breeding sites (i.e. migration phenology) in response to climate change to exploit maximum food availability at higher latitudes and improve their fitness. Despite the impact of changing migration phenology at population and community level, the extent to which individual and species-specific response affects associations among co-migrating species has been seldom explored. By applying temporal co-occurrence network models on 15 years of standardized bird ringing data at a spring stopover site, we show that African–European migratory landbirds tend to migrate in well-defined groups of species with high temporal overlap. Such ‘co-migration fidelity’ significantly increased over the years and was higher in long-distance (trans-Saharan) than in short-distance (North African) migrants. Our findings suggest non-random patterns of associations in co-migrating species, possibly related to the existence of regulatory mechanisms associated with changing climate conditions and different uses of stopover sites, ultimately influencing the global economy of migration of landbirds in the Palearctic– African migration system.
... The transport of body stores is considered energetically expensive, increasing the costs of migration (Pennycuick 1989;Hedenström and Alerstam 1997). Moreover, most barnacle geese currently bypass intermediate spring staging sites in the Baltic and transport an overload of body stores to fly directly from the Wadden Sea to the distant Arctic (see Eichhorn et al. (2009) for an estimate of costs incurred by this strategy). The transportation costs of extra body stores for fuelling long-distance flights and reproduction may contribute to the larger differences in both activity and body condition between individuals of the migratory and resident population prior to spring migration, as compared to autumn, when the difference between the populations is presumed to be mainly caused by the preparation for migratory flight (also see Kölzsch et al. 2016). ...
Performing migratory journeys comes with energetic costs, which have to be compensated within the annual cycle. An assessment of how and when such compensation occurs is ideally done by comparing full annual cycles of migratory and non-migratory individuals of the same species, which is rarely achieved. We studied free-living migratory and resident barnacle geese belonging to the same flyway (metapopulation), and investigated when differences in foraging activity occur, and when foraging extends beyond available daylight, indicating a diurnal foraging constraint in these usually diurnal animals. We compared foraging activity of migratory (N = 94) and resident (N = 30) geese throughout the annual cycle using GPS-transmitters and 3D-accelerometers, and corroborated this with data on seasonal variation in body condition. Migratory geese were more active than residents during most of the year, amounting to a difference of over 370 h over an entire annual cycle. Activity differences were largest during the periods that comprised preparation for spring and autumn migration. Lengthening days during spring facilitated increased activity, which coincided with an increase in body condition. Both migratory and resident geese were active at night during winter, but migratory geese were also active at night before autumn migration, resulting in a period of night-time activity that was 6 weeks longer than in resident geese. Our results indicate that, at least in geese, seasonal migration requires longer daily activity not only during migration but throughout most of the annual cycle, with migrants being more frequently forced to extend foraging activity into the night.
... Reference [62] suggested that increased competition for food at spring stopover sites in the Baltic could explain the recent change in barnacle goose Branta leucopsis northbound migration. The idea that food competition at stopover sites and perhaps also on wintering grounds stiffened appears plausible [63] and could play a role in the spring migration of the greater white-fronted goose. ...
... Stopover sites will continue to degrade and may disappear, save for some areas close to a few northern towns where agriculture is able to persist (see [25], though geese will be in easy reach of hunters there. Geese have two possible counter-strategies, namely (i) to speed up their migration (as the barnacle geese have: [62], which will mean, as a consequence, that they spend longer in Western Europe (thus exacerbating competition there: [62,63], or (ii) to shift to a migration route already in use, from Hungary through Southern Russia, across the Urals and thence, following the Ob and other Siberian rivers towards the Arctic. At present, the second alternative appears to be favoured. ...
... Stopover sites will continue to degrade and may disappear, save for some areas close to a few northern towns where agriculture is able to persist (see [25], though geese will be in easy reach of hunters there. Geese have two possible counter-strategies, namely (i) to speed up their migration (as the barnacle geese have: [62], which will mean, as a consequence, that they spend longer in Western Europe (thus exacerbating competition there: [62,63], or (ii) to shift to a migration route already in use, from Hungary through Southern Russia, across the Urals and thence, following the Ob and other Siberian rivers towards the Arctic. At present, the second alternative appears to be favoured. ...
Stopover sites are vital to the state of the population of many migratory bird species. The greater white-fronted goose Anser albifrons is the most numerous Eurasian goose species, and migrates on a broad front over European Russia. Stopover and staging sites have specific habitat requirements. They are located near open water, have nearby (<5 km) foraging areas, must be open, and lie at least 500 m from the nearest woodland. Extensive agricultural land abandonment in European Russia since 1990 is leading to widespread land cover changes, and may be lowering the availability and perhaps the suitability of stopover sites for greater white-fronted geese. To measure the extent of land cover change, we compiled Landsat images of three areas in European Russia over which geese migrate. The images were taken May 1990, 2002 and 2014, and used to create a scene that covered completely each area in each of these years. We classified each pixel into one of six land cover classes (LCCs: urban, water, arable, grass, peat bog and forest), and tallied the number changing LCC between the successive maps. For ground truthing, we made field visits in June 2014 to 150 locations chosen randomly in advance, and among them, 64 identified as stopover sites recently used by geese. At each, we assessed vegetation composition and cover, successional stage and the duration (in years) since agriculture on the site had been abandoned. The extent of arable land that changed to another classification 1990–2014 was 56%, and was matched closely by the increase in the extent of the ‘grassland’ and ‘forest’ categories, as expected if agricultural abandonment allows vegetation succession to proceed. The magnitude of change around identified stopover sites was similar to that in the areas as a whole. The extent of land cover change in the northern part of European Russia is making migration by greater white-fronted geese more challenging, which is consistent with the documented southward shift in stopover site usage. This could lead to abandonment of the route across northern European Russia altogether, in favour of a longer migration around the expanding boreal forest, which is inhospitable for goose species.
... Releasing captive birds to reinforce goose populations may potentially lead, at least temporally, to increased spatial variation (Meyburg et al. 2017, Mini et al. 2013. However migration may also change rapidly in geese independently of conservation interventions (Eichhorn et al. 2009, Ramo et al. 2015. For example, Greylag Geese Anser anser in Sweden have dramatically changed wintering and migration traditions within generations (Månsson et al. 2022), and Barnacle Geese adjust wintering range in response to late changes in climate and habitat (Tombre et al. 2019). ...
In 2015 and 2016 four Lesser White-fronted Geese (Anser erythropus), a globally threatened species, were caught and tagged during spring migration representing nearly 10% of the entire Swedish breeding population at the time. Two of the birds were followed over more than one season. Tracking data revealed an unexpected wide network of migration corridors and staging sites. Autumn and spring migration differed by stepping-stone sites and migration speed. So far unknown key stopover sites were discovered in Denmark, northern Germany, and Sweden. By using dynamic Brownian bridge movement models, the potential areas that Lesser White-fronted Geese used during migration are described and conservation implications spotlighted. This study provides another important piece of the puzzle describing the migration of Lesser White-fronted Geese in Western Europe.
... Although greater white-fronted goose advanced their departure from some wintering grounds in western Europe (Fox et al., 2012;Gunnarsson & Tómasson, 2011), barnacle goose were found to delay their departure from the Wadden Sea Region by almost 4 weeks (Eichhorn et al., 2009). By this delayed departure, the impact of geese on grassland persists over a longer period, and earlygrowing crops become more vulnerable to foraging geese as well (Fox et al., 2016). ...
... Between the 1980s and 2010s the size of the Russian-Baltic-North Sea population of the barnacle goose has increased by a factor of 30 and it has expanded its breeding range to the Baltic and North Sea region. However, recent monitoring results including the present study suggest that the size of this population may have stabilized at ca. 1.4 million birds(Heldbjerg et al., 2021).Like already documented for other wintering areas of barnacle geese of the Russian-Baltic population, barnacle geese in Rheiderland delayed their departure in the course of the last 15 years(Eichhorn et al., 2009), while the departure of greater white-fronted geese did not change with years. However, the latter finding is in contrast to greater white-fronted geese wintering in the United Kingdom, which advanced their departure by 15 days since 1973(Fox et al., 2012). ...
Escalating conflicts between grassland farming and wintering geese in northern Germany stimulated a long‐term study in order to promote a fair and workable system of compensation of harvest loss. Between 1996 and 2018 standardized experiments were carried out to quantify changes in yield loss and herbage quality. Simultaneously, we weekly monitored the number of geese to relate yield losses to goose numbers and to identify the impact of the different species.
Exclosure experiments were established on conventionally managed grasslands. The number of investigated fields differed over the study period (1990s: n = 6, 2000s: n = 14, 2010s: n = 2–18). On each field, we established 12 marked plots (4.5 m²), six with exclosures from early November until the first cut of grass in May and six with access for the geese. In all plots dry biomass and the quality of herbage (contents of energy, crude protein, crude fibre and ash) were determined at first and second harvest.
The total goose‐dependent yield losses at first harvest increased from 15% in the year 1996/97 to 50% at the end of the 2010s. The increase corresponds with changes in the maximum numbers and the migratory behaviour of the barnacle goose Branta leucopsis. Yield reductions correlated positively with densities of barnacle geese present in April. In contrast, we found no decline in grassland yields with increasing numbers of greater white‐fronted geese Anser albifrons. In all periods second harvest was not affected.
The combined maximum number of both geese which were counted over approximately 23,000 ha of grasslands increased until 2002/03 but levelled off with numbers around 100,000 birds thereafter. While the maximum wintering population of greater white‐fronted geese dropped since 2007/08, the maximum number of barnacle geese increased until mid of 2010s. An increasing proportion of barnacle geese delayed their departure until May.
Within each year grazed plots possessed higher energy and crude protein contents than ungrazed controls, suggesting that the geese maximize their potential nutrient intake rate by grazing.
Synthesis and applications. The present study reveals a significant increase in goose‐related loss of grassland yields which form the basis for a fair and comprehensible system of compensation payments to affected farmers.
... Indeed, temperature and snow cover as well as associated large-scale weather patterns have been identified as important factors affecting the timing of autumn migration for several waterfowl species [19,[61][62][63][64]. While temperature and related weather phenomena may be the ultimate drivers of autumn migration, many other factors, such as wind speed and direction [63,65,66], precipitation [66], human disturbance [67,68], competition [69,70], and predation pressure [71] could influence a specific species' autumn migration phenology, leading to complex patterns [72]. Unfortunately, published data on changes in autumn migration phenology for waterfowl are scarce. ...
Globally, migration phenologies of numerous avian species have shifted over the past half-century. Despite North American waterfowl being well researched, published data on shifts in waterfowl migration phenologies remain scarce. Understanding shifts in waterfowl migration phenologies along with potential drivers is critical for guiding future conservation efforts. Therefore, we utilized historical (1955–2008) nonbreeding waterfowl survey data collected at 21 National Wildlife Refuges in the mid- to lower portion of the Central Flyway to summarize changes in spring and autumn migration phenology. We examined changes in the timing of peak abundance from survey data at monthly intervals for each refuge and species (or species group; n = 22) by year and site-specific temperature for spring (Jan–Mar) and autumn (Oct–Dec) migration periods. For spring (n = 187) and autumn (n = 194) data sets, 13% and 9% exhibited statistically significant changes in the timing of peak migration across years, respectively, while the corresponding numbers for increasing temperatures were 4% and 9%. During spring migration, ≥80% of significant changes in the timing of spring peak indicated advancements, while 67% of significant changes in autumn peak timing indicated delays both across years and with increasing temperatures. Four refuges showed a consistent pattern across species of advancing spring migration peaks over time. Advancements in spring peak across years became proportionally less common among species with increasing latitude, while delays in autumn peak with increasing temperature became proportionally more common. Our study represents the first comprehensive summary of changes in spring and autumn migration phenology for Central Flyway waterfowl and demonstrates significant phenological changes during the latter part of the twentieth century.