Timing of nocturnal passerine migration in Arctic light conditions
Nilsson, Cecilia LU
; Bäckman, Johan
LU
; Karlsson, Håkan
LU
and Alerstam, Thomas
LU
(2015)
In Polar Biology
38(9).
p.1453-1459
- Abstract
- The nocturnal migration of many passerines
starts after sunset and reaches peak intensity during the dark
hours of the night. Birds destined for high Arctic breeding
grounds encounter a special situation, as they will experience
continuous daylight when reaching the high latitudes during
the final part of spring migration. How does this affect the
pattern of nocturnal migration? We consider three alternative
hypotheses; that the period of nocturnal flight activity
may become compressed, remain unchanged or become
disorganized under Arctic light conditions. We tracked migrating
birds by radar north of the Arctic Circle (at Abisko,
68210N,... (More) - The nocturnal migration of many passerines
starts after sunset and reaches peak intensity during the dark
hours of the night. Birds destined for high Arctic breeding
grounds encounter a special situation, as they will experience
continuous daylight when reaching the high latitudes during
the final part of spring migration. How does this affect the
pattern of nocturnal migration? We consider three alternative
hypotheses; that the period of nocturnal flight activity
may become compressed, remain unchanged or become
disorganized under Arctic light conditions. We tracked migrating
birds by radar north of the Arctic Circle (at Abisko,
68210N, 18490E, in Swedish Lapland) and show that the
pattern during the night, with a migration peak around
midnight, persisted even in continuous daylight when the sun
remained above the horizon throughout the 24 h of the day.
The flight intensity peak under continuous daylight in spring
(midnight sun) was very similar to the corresponding peak in
autumn, when the migration took place under twilight conditions.
The duration of the flight period under continuous
daylight in spring lasted 8–10 h and did not seem to be
compressed. We hypothesize that the flight period under
midnight sun conditions may in fact be more protracted than
during short nights, because of release from twilight cues that
tend to synchronize initiation and termination of migratory
flights. These cues will thus capture and confine the flight
period. The results of this provisional study suggest interesting
dynamics in timing of nocturnal migratory flights
under seasonally and latitudinally changing day length
conditions, which will need detailed documentation by future
studies of migration intensity at high-latitude sites. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/7758236
- author
- Nilsson, Cecilia
LU
; Bäckman, Johan
LU
; Karlsson, Håkan
LU
and Alerstam, Thomas
LU
- organization
- publishing date
- 2015
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Polar Biology
- volume
- 38
- issue
- 9
- pages
- 1453 - 1459
- publisher
- Springer
- external identifiers
-
- wos:000359188800012
- scopus:84938742696
- ISSN
- 1432-2056
- DOI
- 10.1007/s00300-015-1708-x
- language
- English
- LU publication?
- yes
- id
- 964b1c50-271c-4f2f-bdaf-b71aaeba7abb (old id 7758236)
- date added to LUP
- 2016-04-01 10:59:10
- date last changed
- 2022-03-12 18:57:20
@article{964b1c50-271c-4f2f-bdaf-b71aaeba7abb,
abstract = {{The nocturnal migration of many passerines<br/><br>
starts after sunset and reaches peak intensity during the dark<br/><br>
hours of the night. Birds destined for high Arctic breeding<br/><br>
grounds encounter a special situation, as they will experience<br/><br>
continuous daylight when reaching the high latitudes during<br/><br>
the final part of spring migration. How does this affect the<br/><br>
pattern of nocturnal migration? We consider three alternative<br/><br>
hypotheses; that the period of nocturnal flight activity<br/><br>
may become compressed, remain unchanged or become<br/><br>
disorganized under Arctic light conditions. We tracked migrating<br/><br>
birds by radar north of the Arctic Circle (at Abisko,<br/><br>
68210N, 18490E, in Swedish Lapland) and show that the<br/><br>
pattern during the night, with a migration peak around<br/><br>
midnight, persisted even in continuous daylight when the sun<br/><br>
remained above the horizon throughout the 24 h of the day.<br/><br>
The flight intensity peak under continuous daylight in spring<br/><br>
(midnight sun) was very similar to the corresponding peak in<br/><br>
autumn, when the migration took place under twilight conditions.<br/><br>
The duration of the flight period under continuous<br/><br>
daylight in spring lasted 8–10 h and did not seem to be<br/><br>
compressed. We hypothesize that the flight period under<br/><br>
midnight sun conditions may in fact be more protracted than<br/><br>
during short nights, because of release from twilight cues that<br/><br>
tend to synchronize initiation and termination of migratory<br/><br>
flights. These cues will thus capture and confine the flight<br/><br>
period. The results of this provisional study suggest interesting<br/><br>
dynamics in timing of nocturnal migratory flights<br/><br>
under seasonally and latitudinally changing day length<br/><br>
conditions, which will need detailed documentation by future<br/><br>
studies of migration intensity at high-latitude sites.}},
author = {{Nilsson, Cecilia and Bäckman, Johan and Karlsson, Håkan and Alerstam, Thomas}},
issn = {{1432-2056}},
language = {{eng}},
number = {{9}},
pages = {{1453--1459}},
publisher = {{Springer}},
series = {{Polar Biology}},
title = {{Timing of nocturnal passerine migration in Arctic light conditions}},
url = {{http://dx.doi.org/10.1007/s00300-015-1708-x}},
doi = {{10.1007/s00300-015-1708-x}},
volume = {{38}},
year = {{2015}},
}