scholarly journals The dependence of long-distance migration to North Norway on environmental conditions in the wintering area and en route

2017 ◽  
Vol 40 ◽  
pp. 14
Author(s):  
Robert T. Barrett
Keyword(s):  
Bird Migration ◽  
Climatic Conditions ◽  
Target Area ◽  
Long Distance ◽  
Early Arrival ◽  
Ultimate Cause ◽  
Arrival Dates ◽  
Wintering Area ◽  
North Norway ◽  
Timing Of Arrival

The onset of bird migration may be under partial endogenous control whereas the timing of movement is flexible with weather and conditions faced by the moving birds being the ultimate cause of variability of arrival dates. This study shows that the early arrival dates of two of three long-distance passerine spring migrants (Willow Warblers Phylloscopus trochilus and Chiffchaffs P. collybita) in North Norway were unrelated to climatic conditions at the start of their migration in Africa and en route through Europe until they reached Scandinavia. Although climate in W Africa may have affected departure dates, the timing of arrival of the first Pied Flycatchers Ficedula hypoleuca seemed to be unrelated to conditions along the whole route, including the target area.

scholarly journals Why is timing of bird migration advancing when individuals are not?

2014 ◽  
Vol 281 (1774) ◽  
pp. 20132161 ◽  
Author(s):  
Jennifer A. Gill ◽  
José A. Alves ◽  
William J. Sutherland ◽  
Graham F. Appleton ◽  
Peter M. Potts ◽  
...  
Keyword(s):  
Rapid Evolution ◽  
Climatic Conditions ◽  
Population Declines ◽  
Migratory Species ◽  
Long Distance ◽  
Breeding Sites ◽  
Timing Of Migration ◽  
Arrival Dates ◽  
Spring Arrival ◽  
New Recruits

Recent advances in spring arrival dates have been reported in many migratory species but the mechanism driving these advances is unknown. As population declines are most widely reported in species that are not advancing migration, there is an urgent need to identify the mechanisms facilitating and constraining these advances. Individual plasticity in timing of migration in response to changing climatic conditions is commonly proposed to drive these advances but plasticity in individual migratory timings is rarely observed. For a shorebird population that has significantly advanced migration in recent decades, we show that individual arrival dates are highly consistent between years, but that the arrival dates of new recruits to the population are significantly earlier now than in previous years. Several mechanisms could drive advances in recruit arrival, none of which require individual plasticity or rapid evolution of migration timings. In particular, advances in nest-laying dates could result in advanced recruit arrival, if benefits of early hatching facilitate early subsequent spring migration. This mechanism could also explain why arrival dates of short-distance migrants, which generally return to breeding sites earlier and have greater scope for advance laying, are advancing more rapidly than long-distance migrants.

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 Consistency in long-distance bird migration: contrasting patterns in time and space for two raptors

2016 ◽  
Vol 113 ◽  
pp. 177-187 ◽  
Author(s):  
Yannis Vardanis ◽  
Jan-Åke Nilsson ◽  
Raymond H.G. Klaassen ◽  
Roine Strandberg ◽  
Thomas Alerstam
Keyword(s):  
Bird Migration ◽  
Time And Space ◽  
Long Distance

scholarly journals Variation in winter site fidelity within and among individuals influences movement behavior in a partially migratory ungulate

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0258128
Author(s):  
Timothy J. Fullman ◽  
Brian T. Person ◽  
Alexander K. Prichard ◽  
Lincoln S. Parrett
Keyword(s):  
Site Fidelity ◽  
Rangifer Tarandus ◽  
First Passage Time ◽  
Cost Benefit ◽  
Movement Behavior ◽  
Long Distance ◽  
Directed Movement ◽  
Movement Trajectories ◽  
Wintering Areas ◽  
Wintering Area

Many animals migrate to take advantage of temporal and spatial variability in resources. These benefits are offset with costs like increased energetic expenditure and travel through unfamiliar areas. Differences in the cost-benefit ratio for individuals may lead to partial migration with one portion of a population migrating while another does not. We investigated migration dynamics and winter site fidelity for a long-distance partial migrant, barren ground caribou (Rangifer tarandus granti) of the Teshekpuk Caribou Herd in northern Alaska. We used GPS telemetry for 76 female caribou over 164 annual movement trajectories to identify timing and location of migration and winter use, proportion of migrants, and fidelity to different herd wintering areas. We found within-individual variation in movement behavior and wintering area use by the Teshekpuk Caribou Herd, adding caribou to the growing list of ungulates that can exhibit migratory plasticity. Using a first passage time–net squared displacement approach, we classified 78.7% of annual movement paths as migration, 11.6% as residency, and 9.8% as another strategy. Timing and distance of migration varied by season and wintering area. Duration of migration was longer for fall migration than for spring, which may relate to the latter featuring more directed movement. Caribou utilized four wintering areas, with multiple areas used each year. This variation occurred not just among different individuals, but state sequence analyses indicated low fidelity of individuals to wintering areas among years. Variability in movement behavior can have fitness consequences. As caribou face the pressures of a rapidly warming Arctic and ongoing human development and activities, further research is needed to investigate what factors influence this diversity of behaviors in Alaska and across the circumpolar Arctic.

Xanthomonas cassavae. [Descriptions of Fungi and Bacteria].

2000 ◽  
Author(s):  
G. S. Saddler
Keyword(s):  
Geographical Distribution ◽  
Systemic Infection ◽  
Climatic Conditions ◽  
Euphorbia Pulcherrima ◽  
Disease Development ◽  
Long Distance ◽  
Green Point ◽  
Leaf Spots ◽  
Strong Winds ◽  
Dark Green

Abstract A description is provided for Xanthomonas cassavae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Manihot esculenta (Euphorbiaceae); by artificial inoculation: Euphorbia pulcherrima (Euphorbiaceae). DISEASE: Cassava leaf spot or bacterial necrosis. Angular leaf spots extend along veins but generally do not develop into blight. Spots age, turn dark brown and are surrounded by a yellow halo. Exudate is frequently produced. On stems, dark green point lesions develop slowly up to 1 cm diam. Lytic pockets generally develop under lesions in the cortex. Lateral extension can lead to girdling and tip dieback. Secondary colonization by Colletotrichum gloeosporioides[Glomerella cingulata] is frequently observed. Systemic infection and vascular browning are absent or very restricted. Entry into the host is through natural openings (stomata) or epidermal wounds, which can be caused (especially on the stem) by sand particles or small grains of gravel thrown up by the strong winds which precede the first rains. The optimum temperature for disease development is 25°C. Disease mainly occurs above altitudes of 800 m. There is evidence that disease severity is linked to poor plant nutrition. GEOGRAPHICAL DISTRIBUTION: AFRICA: Burundi, Congo Democratic Republic, Kenya, Malawi, Niger, Rwanda, Tanzania, Uganda, Zaire. SOUTH AMERICA: Colombia. TRANSMISSION: Long distance spread is restricted. Symptomless cuttings taken from diseased plants were unable to demonstrate propagation. Rapid disease development under favourable climatic conditions suggests a symptomless epiphytic phase on the host itself or on a plant other than cassava. In the field, dispersal is by wind and rain.

Seed dispersal, spatial distribution and population structure of Brazilnut trees (Bertholletia excelsa) in southeastern Amazonia

1997 ◽  
Vol 13 (4) ◽  
pp. 595-616 ◽  
Author(s):  
Carlos A. Peres ◽  
Claudia Baider
Keyword(s):  
Spatial Distribution ◽  
Seed Dispersal ◽  
Average Distance ◽  
Climatic Conditions ◽  
Long Distance ◽  
Neotropical Forests ◽  
Bertholletia Excelsa ◽  
Entire Study ◽  
Natural Stands ◽  
Seed Shadows

ABSTRACTSeeds of the Brazilnut tree (Bertholletia excelsa Humb. & Bonpl., Lecythidaceae) sustain one of the most important extractive industries in neotropical forests. Yet little is known about the demography and seed dispersal ecology of Bertholletia, particularly in natural stands which have not been previously harvested. This study presents data on the population density, spatial distribution, and seed dispersal ecology of Brazilnut trees at a pristine stand located within the Kayapó Indian Area of southeastern Amazonia, Pará, Brazil. Brazilnut trees were primarily found within groves (castanhais) of 75 to 149 trees, with a few isolated trees in between. Although the density of trees ≥ 10 cm in diameter at breast height (hereafter, dbh) at two groves was 4.8 to 5.1 trees ha–1, the overall density for the entire study area of c. 950 ha was estimated at 1.3 tree ha–1. Within-grove nearest neighbour distances averaged 21 m and were markedly skewed towards even shorter distances. Seed dispersal experiments using 709 marked seeds indicated that this pattern can be largely explained by the highly restricted seed shadows imparted by the main seed dispersal agents of Bertholletia at this site, the red-rumped agouti (Dasyprocta leporina). Agoutis on average scatterhoard Bertholletia seeds to an average distance of 5 m, and rarely beyond 20 m, from seed stations. We suggest that, once edaphic and climatic conditions are suitable, the highly contagious spatial distribution of Bertholletia trees at the landscape level can be largely accounted for by the quantitatively dominant effect of short-distance dispersal by caviomorph rodents, and rare events of long-distance dispersal provided by other vectors. This mechanism of grove formation need not resort to untested conjectures of human dispersal and intentional planting in prehistoric and historic times as it has often been suggested in the literature.

scholarly journals Long-distance dispersal of the beach strawberry, Fragaria chiloensis, from North America to Chile and Hawaii

2020 ◽  
Author(s):  
James F Hancock ◽  
Harold H Prince
Keyword(s):  
North America ◽  
Bird Migration ◽  
Aleutian Islands ◽  
South American ◽  
Rocky Shores ◽  
Long Distance Dispersal ◽  
Feeding Preferences ◽  
Long Distance ◽  
Central California ◽  
Fragaria Chiloensis

Abstract Background and Aims The beach strawberry, Fragaria chiloensis, is found in a narrow coastal band from the Aleutian Islands to central California and then jumps thousands of kilometres all the way to Hawaii and Chile. As it probably had a North American origin, it must have been introduced to the other locations by long-distance dispersal. The aim of this study was to determine which agent carried the beach strawberry to its Pacific and South American locations. Methods A deductive framework was constructed to separate between the possible modes of long-distance dispersal involving animals, wind and ocean currents. Bird migration was subsequently identified as the most likely scenario, and then the routes, habitats, feeding preferences and flight distances of all the shorebird species were evaluated to determine the most likely carrier. Key Results Six species migrate between North America and Chile and feed on the beaches and rocky shores where F. chiloensis grows naturally: Black-bellied Plovers, Greater Yellowlegs, Ruddy Turnstones, Sanderlings, Whimbrels and Willets. Of these, only two eat fruit and migrate in long continuous flight: Ruddy Turnstones and Whimbrels. Two species travel between North America and Hawaii, eat fruit and forage on the beaches and rocky shores where F. chiloensis grows naturally: Pacific Golden-plovers and Ruddy Turnstones. Ruddy Turnstones eat far less fruit than Pacific Golden-plovers and Whimbrels, making them less likely to have introduced the beach strawberry to either location. Conclusions We provide evidence that F. chiloesis seeds were probably dispersed to Hawaii by Pacific Golden-plovers and to Chile by Whimbrels.

scholarly journals All across Africa: highly individual migration routes of Eleonora's falcon

2008 ◽  
Vol 275 (1653) ◽  
pp. 2887-2896 ◽  
Author(s):  
Marion Gschweng ◽  
Elisabeth K.V Kalko ◽  
Ulrich Querner ◽  
Wolfgang Fiedler ◽  
Peter Berthold
Keyword(s):  
West Africa ◽  
Satellite Telemetry ◽  
Late Summer ◽  
Breeding Period ◽  
Migration Route ◽  
Migration Routes ◽  
Long Distance ◽  
Wintering Area ◽  
Eleonora’S Falcon ◽  
Falco Eleonorae

Eleonora's falcon ( Falco eleonorae ) is a rare raptor species that delays its breeding period until late summer to feed its young with passerines at the peak of autumn migration. Since the 1950s, this slender winged falcon has been believed to migrate along a historical route via the Red Sea to its main wintering area in Madagascar. In our study, we used satellite telemetry to investigate the real migration route of Eleonora's falcons and found that the species displayed a highly individual migration pattern. Furthermore, juvenile falcons migrated via West Africa to Madagascar and two juveniles could be tracked during spring migration and to their summering areas in East and West Africa. As juveniles migrated independently of adults, we discuss inherited navigation strategies forming part of a complex navigation system. We propose the idea of an orientation mechanism that naive falcons could apply during their long-distance migration towards their faraway wintering area located in the open ocean.

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