Extreme altitudes during diurnal flights in a nocturnal songbird migrant

Research output: Contribution to journalArticle


Billions of nocturnally migrating songbirds fly across oceans and deserts on their annual journeys. Using multisensor data loggers, we show that great reed warblers (Acrocephalus arundinaceus) regularly prolong their otherwise strictly nocturnal flights into daytime when crossing the Mediterranean Sea and the Sahara Desert. Unexpectedly, when prolonging their flights, they climbed steeply at dawn, from a mean of 2394 meters above sea level to reach extreme cruising altitudes (mean 5367 and maximum 6267 meters above sea level) during daytime flights. This previously unknown behavior of using exceedingly high flight altitudes when migrating during daytime could be caused by diel variation in ambient temperature, winds, predation, vision range, and solar radiation. Our finding of this notable behavior provides new perspectives on constraints in bird flight and might help to explain the evolution of nocturnal migration.


External organisations
  • University of Copenhagen
  • Lithuanian Nature Research Centre
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Zoology
Original languageEnglish
Pages (from-to)646-648
Number of pages3
Issue number6542
Publication statusPublished - 2021 May 7
Publication categoryResearch