klaassen-differencesinonground-2022.pdf (1.96 MB)
Differences in on-ground and aloft conditions explain seasonally different migration paths in Demoiselle crane
journal contribution
posted on 2022-01-01, 00:00 authored by Batbayar Galtbalt, Nyambayar Batbayar, Tuvshintugs Sukhbaatar, Bernd Vorneweg, Georg Heine, Uschi Müller, Martin Wikelski, Marcel KlaassenMarcel KlaassenAbstract
Background: Although some migratory birds may take different routes during their outbound and inbound migration, the factors causing these differential migrations to and from the breeding grounds, have rarely been investigated.In Northeast Asia, Demoiselle crane (Anthropoides virgo) performs one of the most extreme “loop” migrations known to date. During outbound migration, they cross the Himalayas to non-breeding sites in northwest India. Contrastingly, during inbound migration to the breeding grounds, they fly around the western end of the Himalayas. We hypothesise that differences in prevailing environmental conditions aloft and/or on-ground during both seasonal migrations are at the core of this phenomenon.
Methods: Based on the tracking data of 16 individuals of tagged Demoiselle crane, we compared conditions during
actual migration with those of simulated “reverse” migration (i.e. by adding 180 degrees to the flight direction and adding and subtracting half a year to the timestamps of outbound and inbound migration, respectively).
Results: The comparison of actual and simulated “reverse” migration indicated that cranes would have encountered
poorer aloft (wind support and thermal uplift) and on-ground conditions (temperature) if they had migrated in a
reverse outbound migration and poorer on-ground conditions (Normalised Difference Vegetation Indexes [NDVI]) if they had migrated in a reverse inbound direction.
Conclusions: Our analyses suggest that both on-ground and aloft conditions play a key role in explaining Demoiselle cranes’ loop migration, during the periods that they chose to use these alternative routes. Knowledge on the determinants of (differential) migration routes allow predicting migration decisions and may be critical in mitigating global change effects on animal migrations.
Background: Although some migratory birds may take different routes during their outbound and inbound migration, the factors causing these differential migrations to and from the breeding grounds, have rarely been investigated.In Northeast Asia, Demoiselle crane (Anthropoides virgo) performs one of the most extreme “loop” migrations known to date. During outbound migration, they cross the Himalayas to non-breeding sites in northwest India. Contrastingly, during inbound migration to the breeding grounds, they fly around the western end of the Himalayas. We hypothesise that differences in prevailing environmental conditions aloft and/or on-ground during both seasonal migrations are at the core of this phenomenon.
Methods: Based on the tracking data of 16 individuals of tagged Demoiselle crane, we compared conditions during
actual migration with those of simulated “reverse” migration (i.e. by adding 180 degrees to the flight direction and adding and subtracting half a year to the timestamps of outbound and inbound migration, respectively).
Results: The comparison of actual and simulated “reverse” migration indicated that cranes would have encountered
poorer aloft (wind support and thermal uplift) and on-ground conditions (temperature) if they had migrated in a
reverse outbound migration and poorer on-ground conditions (Normalised Difference Vegetation Indexes [NDVI]) if they had migrated in a reverse inbound direction.
Conclusions: Our analyses suggest that both on-ground and aloft conditions play a key role in explaining Demoiselle cranes’ loop migration, during the periods that they chose to use these alternative routes. Knowledge on the determinants of (differential) migration routes allow predicting migration decisions and may be critical in mitigating global change effects on animal migrations.
History
Journal
Movement EcologyVolume
10Article number
4Pagination
1 - 11Publisher
BioMed CentralLocation
London, Eng.Publisher DOI
Link to full text
eISSN
2051-3933Language
engPublication classification
C1 Refereed article in a scholarly journalUsage metrics
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Keywords
Anthropoides virgoEnvironmental conditionsLoop migration,NDVITemperatureThermalsWind support,Science & TechnologyLife Sciences & BiomedicineEcologyEnvironmental Sciences & EcologyLoop migrationWind supportWIND CONDITIONSATMOSPHERIC CONDITIONSPACIFIC-OCEANCOMMON CRANEANNUAL CYCLESTOPOVERSTRATEGIESDETOURSEcology
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