scholarly journals Mechanistic movement models identify continuously updated autumn migration cues in Arctic caribou

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Matthew D. Cameron ◽  
Joseph M. Eisaguirre ◽  
Greg A. Breed ◽  
Kyle Joly ◽  
Knut Kielland
Keyword(s):  
Environmental Conditions ◽  
Rangifer Tarandus ◽  
Continuous Process ◽  
Population Level ◽  
Spring Migration ◽  
The Arctic ◽  
Autumn Migration ◽  
Long Distance ◽  
Movement Model ◽  
Migratory Patterns

Abstract Background Migrations in temperate systems typically have two migratory phases, spring and autumn, and many migratory ungulates track the pulse of spring vegetation growth during a synchronized spring migration. In contrast, autumn migrations are generally less synchronous and the cues driving them remain understudied. Our goal was to identify the cues that migrants use in deciding when to initiate migration and how this is updated while en route. Methods We analyzed autumn migrations of Arctic barren-ground caribou (Rangifer tarandus) as a series of persistent and directional movements and assessed the influence of a suite of environmental factors. We fitted a dynamic-parameter movement model at the individual-level and estimated annual population-level parameters for weather covariates on 389 individual-seasons across 9 years. Results Our results revealed strong, consistent effects of decreasing temperature and increasing snow depth on migratory movements, indicating that caribou continuously update their migratory decision based on dynamic environmental conditions. This suggests that individuals pace migration along gradients of these environmental variables. Whereas temperature and snow appeared to be the most consistent cues for migration, we also found interannual variability in the effect of wind, NDVI, and barometric pressure. The dispersed distribution of individuals in autumn resulted in diverse environmental conditions experienced by individual caribou and thus pronounced variability in migratory patterns. Conclusions By analyzing autumn migration as a continuous process across the entire migration period, we found that caribou migration was largely related to temperature and snow conditions experienced throughout the journey. This mechanism of pacing autumn migration based on indicators of the approaching winter is analogous to the more widely researched mechanism of spring migration, when many migrants pace migration with a resource wave. Such a similarity in mechanisms highlights the different environmental stimuli to which migrants have adapted their movements throughout their annual cycle. These insights have implications for how long-distance migratory patterns may change as the Arctic climate continues to warm.

scholarly journals Increased Stopover Duration and Low Body Condition of the Pied Flycatcher (Ficedula hypoleuca) at an Autumn Stopover Site

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2208
Author(s):  
Bernice Goffin ◽  
Marcial Felgueiras ◽  
Anouschka R. Hof
Keyword(s):  
Environmental Change ◽  
Body Condition ◽  
Environmental Conditions ◽  
Ficedula Hypoleuca ◽  
Autumn Migration ◽  
Long Distance ◽  
Stopover Site ◽  
Stopover Duration ◽  
Stopover Sites ◽  
Over Time

Many long-distance migratory bird species are in decline, of which environmental changes, such as climate change and land-use changes, are thought to be important drivers. The effects of environmental change on the migration of these birds have often been studied during spring migration. Fewer studies have explored the impacts of environmental change on autumn migration, especially at stopover sites. However, stopover sites are important, as the quality of these sites is expected to change over time. We investigated impacts of local environmental conditions on the migration strategy and body condition of the Pied Flycatcher (Ficedula hypoleuca) at an autumn migration stopover site using long-term ringing data (1996–2018) and local environmental conditions. We found that although the arrival and departure dates of birds at the stopover site remained unchanged, the body condition (fat score) of the individuals caught decreased, and the stopover duration increased. This suggests that conditions at the stopover site during the autumn migration period have deteriorated over time. This study emphasizes the importance of suitable stopover sites for migratory birds and stresses that changes in environmental conditions during the autumn migration period may be contributing to the current decline in long-distance migratory passerines.

scholarly journals Simple rules guide dragonfly migration

2006 ◽  
Vol 2 (3) ◽  
pp. 325-329 ◽  
Author(s):  
Martin Wikelski ◽  
David Moskowitz ◽  
James S Adelman ◽  
Jim Cochran ◽  
David S Wilcove ◽  
...  
Keyword(s):  
Decision Rules ◽  
Population Level ◽  
Long Distance ◽  
Migration Strategy ◽  
Anax Junius ◽  
Wind Speeds ◽  
Radio Transmitters ◽  
Migratory Patterns ◽  
And Migration ◽  
Made In

Every year billions of butterflies, dragonflies, moths and other insects migrate across continents, and considerable progress has been made in understanding population-level migratory phenomena. However, little is known about destinations and strategies of individual insects. We attached miniaturized radio transmitters ( ca 300 mg) to the thoraxes of 14 individual dragonflies (common green darners, Anax junius ) and followed them during their autumn migration for up to 12 days, using receiver-equipped Cessna airplanes and ground teams. Green darners exhibited distinct stopover and migration days. On average, they migrated every 2.9±0.3 days, and their average net advance was 58±11 km in 6.1±0.9 days (11.9±2.8 km d −1 ) in a generally southward direction (186±52°). They migrated exclusively during the daytime, when wind speeds were less than 25 km h −1 , regardless of wind direction, but only after two nights of successively lower temperatures (decrease of 2.1±0.6 °C in minimum temperature). The migratory patterns and apparent decision rules of green darners are strikingly similar to those proposed for songbirds, and may represent a general migration strategy for long-distance migration of organisms with high self-propelled flight speeds.

scholarly journals The familiar area hypothesis and movement patterns of wild forest reindeer in Karelia, Northern Europe

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 235 ◽  
Author(s):  
E. Pulliainen ◽  
P. I. Danilov ◽  
K. Heikura ◽  
E. Erkinaro ◽  
S. Sulkava ◽  
...  
Keyword(s):  
Small Groups ◽  
Rangifer Tarandus ◽  
Movement Patterns ◽  
Spring Migration ◽  
Exploratory Behaviour ◽  
Autumn Migration ◽  
Northern Europe ◽  
Migration Routes ◽  
Migration Period ◽  
Restricted Area

The relevance of the familiar area hypothesis to the behaviour of the wild forest reindeer (Rangifer tarandus fennicus Lönnb.) was studied in a Fenno-Soviet project by radio and field tracking of these ungulates in Karelia, Northern Europe, in 1978 - 1985. This subpopulation (500 - 600 exx.) has a tradition of overwintering in a restricted area around Lake Lentua (ca. 1000 km2). The spring migration period is shorter in length than the autumn migration. The migration routes are generally the same in autumn and spring, although exceptions occur, indicating exploratory behaviour. The large winter herds disband into small groups or lone individuals for the summertime, when this subpopulation is spread over a much wider area (ca. 5400 km2). It is concluded that the observations made support the familiar area hypothesis in all essential points.

scholarly journals Migration Strategies of Common Buzzard (Buteo buteo Linnaeus, 1758) in Dobruja

2017 ◽  
Vol 60 (2) ◽  
pp. 537-545
Author(s):  
Cătălin-Răzvan Stanciu ◽  
Răzvan Zaharia ◽  
Gabriel-Bogdan Chişamera ◽  
Ioana Cobzaru ◽  
Viorel-Dumitru Gavril ◽  
...  
Keyword(s):  
Spring Migration ◽  
Autumn Migration ◽  
Migration Behavior ◽  
Significant Activity ◽  
Long Distance ◽  
Common Buzzard ◽  
Time Period ◽  
Migration Strategies ◽  
The Common ◽  
Vantage Points

Abstract We studied various aspects regarding migration behavior of the Common Buzzard for two subspecies (B. b. buteo and B. b. vulpinus) transiting the region which overlaps with the Western Black Sea Corridor. Using vantage points set across Dobruja we managed to count 2,662 individuals. We highlighted the seasonal and diurnal peak passage, flight directions and height of flight for each season. Our results suggest that 57% of the counted individuals belongs to long-distance migrant Steppe Buzzard - B. b. vulpinus. The peek passage period in autumn migration was reached between the 26th of September to the 6th of October, while for the spring migration peek passage remained uncertain. The main autumn passage direction was from N to S, and NNW to SSE but also from NE to SW. For spring passage the main direction was from S to N but also from ESE to WNW. Flight height during autumn migration was mostly at high altitude while in spring migration was more evenly distributed. The most significant activity was recorded in the second time period, between 10:01 and 13:00 (43%).

scholarly journals No general shift in spring migration phenology by eastern North American birds since 1970

2021 ◽  
Author(s):  
André Desrochers ◽  
Andra Florea ◽  
Pierre-Alexandre Dumas
Keyword(s):  
Short Distance ◽  
Species Abundance ◽  
Open Water ◽  
Early Spring ◽  
Spring Migration ◽  
The Arctic ◽  
Long Distance ◽  
Arrival Dates ◽  
Migration Phenology ◽  
First Arrival

We studied the phenology of spring bird migration from eBird and ÉPOQ checklist programs South of 49°N in the province of Quebec, Canada, between 1970 and 2020. 152 species were grouped into Arctic, long-distance, and short-distance migrants. Among those species, 75 significantly changed their migration dates, after accounting for temporal variability in observation effort, species abundance, and latitude. But in contrast to most studies on the subject, we found no general advance in spring migration dates, with 36 species advancing and 39 species delaying their migration. Several early-migrant species associated to open water advanced their spring migration, possibly due to decreasing early-spring ice cover in the Great Lakes and the St-Lawrence river since 1970. Arctic breeders and short-distance migrants advanced their first arrival dates more than long-distance migrants not breeding in the arctic. However, there was no difference among migrant groups when median arrival dates were considered. We conclude that general claims about advances in spring migration dates in eastern North America are misleading due to large taxonomic variation.

scholarly journals Advancement in long-distance bird migration through individual plasticity in departure

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jesse R. Conklin ◽  
Simeon Lisovski ◽  
Phil F. Battley
Keyword(s):  
Bird Migration ◽  
Population Level ◽  
Breeding Site ◽  
Environmental Constraints ◽  
Adaptive Responses ◽  
Long Distance ◽  
Direct Observations ◽  
Breeding Resources ◽  
Plastic Responses

AbstractGlobally, bird migration is occurring earlier in the year, consistent with climate-related changes in breeding resources. Although often attributed to phenotypic plasticity, there is no clear demonstration of long-term population advancement in avian migration through individual plasticity. Using direct observations of bar-tailed godwits (Limosa lapponica) departing New Zealand on a 16,000-km journey to Alaska, we show that migration advanced by six days during 2008–2020, and that within-individual advancement was sufficient to explain this population-level change. However, in individuals tracked for the entire migration (50 total tracks of 36 individuals), earlier departure did not lead to earlier arrival or breeding in Alaska, due to prolonged stopovers in Asia. Moreover, changes in breeding-site phenology varied across Alaska, but were not reflected in within-population differences in advancement of migratory departure. We demonstrate that plastic responses can drive population-level changes in timing of long-distance migration, but also that behavioral and environmental constraints en route may yet limit adaptive responses to global change.

scholarly journals Quantifying the consequence of applying conservative assumptions in the assessment of oil spill effects on polar cod (Boreogadus saida) populations

Polar Biology ◽  
2021 ◽  
Vol 44 (3) ◽  
pp. 575-586
Author(s):  
Pepijn De Vries ◽  
Jacqueline Tamis ◽  
Jasmine Nahrgang ◽  
Marianne Frantzen ◽  
Robbert Jak ◽  
...  
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Population Level ◽  
Threshold Concentration ◽  
The Arctic ◽  
Polar Cod ◽  
Boreogadus Saida ◽  
Precautionary Approach ◽  
Recovery Duration ◽  
The Impact

AbstractIn order to assess the potential impact from oil spills and decide the optimal response actions, prediction of population level effects of key resources is crucial. These assessments are usually based on acute toxicity data combined with precautionary assumptions because chronic data are often lacking. To better understand the consequences of applying precautionary approaches, two approaches for assessing population level effects on the Arctic keystone species polar cod (Boreogadus saida) were compared: a precautionary approach, where all exposed individuals die when exposed above a defined threshold concentration, and a refined (full-dose-response) approach. A matrix model was used to assess the population recovery duration of scenarios with various but constant exposure concentrations, durations and temperatures. The difference between the two approaches was largest for exposures with relatively low concentrations and short durations. Here, the recovery duration for the refined approach was less than eight times that found for the precautionary approach. Quantifying these differences helps to understand the consequences of precautionary assumptions applied to environmental risk assessment used in oil spill response decision making and it can feed into the discussion about the need for more chronic toxicity testing. An elasticity analysis of our model identified embryo and larval survival as crucial processes in the life cycle of polar cod and the impact assessment of oil spills on its population.

scholarly journals Seasonal differences in migration strategies of Red Kites (Milvus milvus) wintering in Spain

2021 ◽  
Author(s):  
Jorge García-Macía ◽  
Javier Vidal-Mateo ◽  
Javier De La Puente ◽  
Ana Bermejo ◽  
Rainer Raab ◽  
...  
Keyword(s):  
Spring Migration ◽  
Great Variability ◽  
Autumn Migration ◽  
Seasonal Differences ◽  
North Eastern ◽  
Wintering Areas ◽  
Satellite Transmitters ◽  
Migration Strategies ◽  
Migratory Movements ◽  
Milvus Milvus

AbstractRed Kite shows a great variability in its migration strategies: most individuals in north-eastern Europe are migrants, but there is also a growing number of sedentary individuals. Here, we tagged 49 Red Kites wintering in Spain with GPS/satellite transmitters between 2013 and 2020 to study the autumn and spring migration between the breeding or summering areas in Central Europe and the wintering quarters in Spain. In first place, differences between immatures and adults were found for spring migration. Adults began the spring migration towards the northeast in February–March while the immature individuals began to migrate significantly later and showing a wider date range (February-June). Adults also takes significantly less days to arrive at their destinations (12 ± 5 days) and cover more distance per day (134.2 ± 37.1 km/day) than immatures (19 ± 11 days and 98.9 ± 21.2 km/day). In second place, we also found differences between spring and autumn migration (excluding immatures). Spring migrations were clearly faster and with less stopovers days than autumn migrations. Autumn migration began between mid-October and late November and two different behaviours were observed: most birds made a quick migration direct to the wintering areas with only some days of stopovers, but others prolonged the migration with long stops along the route. These results highlight a great variation in the migratory movements of Red Kite, not only according to age but also between individuals and seasons.

scholarly journals Geolocators reveal migration routes, stopover sites, and nonbreeding dispersion in a population of Cerulean Warblers

2020 ◽  
Vol 7 (1) ◽  
pp. 19-26
Author(s):  
Clayton D Delancey ◽  
Kamal Islam ◽  
Gunnar R Kramer ◽  
Garrett J MacDonald ◽  
Alexander R Sharp ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Spring Migration ◽  
Autumn Migration ◽  
Migration Routes ◽  
Neotropical Migrant ◽  
Wood Warblers ◽  
Before And After ◽  
The Caribbean ◽  
Declining Species ◽  
Cerulean Warblers

AbstractCerulean Warblers (Setophaga cerulea) are among the fastest declining Nearctic-Neotropical migrant wood-warblers (Parulidae) in North America. Despite ongoing conservation efforts, little is known about their non-breeding distribution. In June 2016-2018, we deployed geolocators (n = 30) on adult male Cerulean Warblers in Indiana, USA, to track annual movements of individuals. Recovered geolocators (n = 4) showed that Cerulean Warblers occurred broadly throughout northern South America. Autumn migration lasted 44-71 days (n = 4), whereas spring migration lasted 37-41 days (n = 3). The average migration distance was 5268 km. During autumn migration, Cerulean Warblers made 1-4 stopovers (i.e., ≥2 days; n = 4) and 1-2 stopovers during spring migration (n = 3). When crossing the Gulf of Mexico during autumn migration, two birds stopped over after crossing, but not beforehand. Two others navigated through the Caribbean rather than crossing the Gulf of Mexico. During spring migration, one individual stopped after crossing, one individual stopped before crossing, and one individual stopped before and after crossing the Gulf of Mexico. No birds migrated through the Caribbean Islands during spring migration. These results represent novel information describing annual movements of individual Cerulean Warblers and will inform conservation efforts for this declining species.

scholarly journals Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

Polar Biology ◽  
2021 ◽  
Vol 44 (2) ◽  
pp. 237-257
Author(s):  
Rebecca Shaftel ◽  
Daniel J. Rinella ◽  
Eunbi Kwon ◽  
Stephen C. Brown ◽  
H. River Gates ◽  
...  
Keyword(s):  
Prey Availability ◽  
Population Level ◽  
The Arctic ◽  
Environmental Drivers ◽  
Chick Survival ◽  
The North ◽  
Phenological Mismatch ◽  
Nesting Sites ◽  
North American Arctic

AbstractAverage annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers affecting invertebrate availability, we modeled the biomass of invertebrates captured in modified Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confirmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively affected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey availability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level effects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.

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