Avian migrants may fly at a range of altitudes, but usually concentrate near strata where a combination of flight conditions is favourable. The aerial environment can have a large impact on the performance of the migrant and is usually highly dynamic, making it beneficial for a bird to regularly check the flight conditions at alternative altitudes. We recorded the migrations between northern Europe and sub-Saharan Africa of European nightjars Caprimulgus europaeus to explore their altitudinal space use during spring and autumn flights and to test whether their climbs and descents were performed according to predictions from flight mechanical theory. Spring migration across all regions was associated with more exploratory vertical flights involving major climbs, a higher degree of vertical displacement within flights, and less time spent in level flight, although flight altitude per se was only higher during the Sahara crossing. The nightjars commonly operated at ascent rates below the theoretical maximum, and periods of descent were commonly undertaken by active flight, and rarely by gliding flight, which has been assumed to be a cheaper locomotion mode during descents. The surprisingly frequent flight-altitude shifts further suggest that nightjars can perform vertical displacements at a relatively low cost, which is expected if the birds can allocate potential energy gained during climbs to thrust forward movement during descents. The results should inspire future studies on the potential costs associated with frequent altitude changes and their trade-offs against anticipated flight condition improvements for aerial migrants.
Flight altitude dynamics of migrating European nightjars across regions and seasons
- Award Group:
- Funder(s): Vetenskapsrādet
- Award Id(s): 621-2012-3585
- Funder(s):
- Award Group:
- Funder(s): Knut och Alice Wallenbergs Stiftelse
- Award Id(s): KAW 2020.0096
- Funder(s):
Currently Viewing Accepted Manuscript - Newer Version Available
- Split-screen
- Views Icon Views
- Open the PDF for in another window
-
Article Versions Icon
Versions
- Version of Record 25 October 2021
- Accepted Manuscript 14 October 2021
- Share Icon Share
-
Tools Icon
Tools
- Search Site
Gabriel Norevik, Susanne Åkesson, Arne Andersson, Johan Bäckman, Anders Hedenström; Flight altitude dynamics of migrating European nightjars across regions and seasons. J Exp Biol 2021; jeb.242836. doi: https://doi.org/10.1242/jeb.242836
Download citation file:
Advertisement
2023 JEB Outstanding Paper Prize shortlist and winner
The JEB Editors are delighted to announce the shortlisted authors for the 2023 JEB Outstanding Paper Prize. Read the winning paper - Tiny spies: mosquito antennae are sensitive sensors for eavesdropping on frog calls - by Hoover Pantoja-Sanchez and Brian Leavell from Ximena Bernal's lab at Purdue University, USA.
JEB Science Communication Workshop for ECRs
If you’re an early-career researcher interested in science communication and are attending the SEB Annual Conference in Prague this summer, come a day early and join the JEB Editors at a sci comm workshop to learn the key writing skills needed to promote your research to a broad audience beyond your peers (1 July at 14.30-17.30). Places are limited to 24 attendees, and applicants should apply through the SEB registration page by 30 April 2024.
Bridging the gap between controlled conditions and natural habitats in understanding behaviour
Novel technologies enable behavioural experiments with non-model species, in naturalistic habitats and with underexplored behaviours. In their Commentary, Scholz and colleagues discuss how to obtain a deeper understanding of the natural ecology and lifestyle of study animals.
How a macrourid fish remains buoyant at depths it should be unable to reach
Fish with swimbladders should not be capable of descending below 7200m, but when Alan Jamieson and Todd Bond spotted a macrourid fish at 7259m, they knew they had seen something miraculous. Working with Imantes Priede, they reveal that the swimbladder of a 1 kg fish could hold 37.9 g of oxygen, sufficient to offset the weight of the fish's bones, and take 221-440 days to fill, which is plausible because it takes years for the fish to descend to such depths.
ECR Workshop on Positive Peer Review
Are you an ECR looking for tips on how to write concise, astute and useful manuscript reviews? If so, join the JEB Editors at a 2-hour JEB-sponsored Workshop on Positive Peer Review at the Canadian Society of Zoologists annual meeting in Moncton on 9 May 2024 at 13.00-15.00. There are 25 spaces for ECRs and selection is first come, first serve. To sign up, check the ECR Workshop box when you register for the CSZ meeting.