The lunar cycle drives migration of a nocturnal bird

PLoS Biol. 2019 Oct 15;17(10):e3000456. doi: 10.1371/journal.pbio.3000456. eCollection 2019 Oct.

Abstract

Every year, billions of seasonal migrants connect continents by transporting nutrients, energy, and pathogens between distant communities and ecosystems. For animals that power their movements by endogenous energy stores, the daily energy intake rates strongly influence the speed of migration. If access to food resources varies cyclically over the season, migrants sensitive to changes in daily energy intake rates may adjust timing of migration accordingly. As an effect, individuals adjusting to a common temporal cycle are expected to approach synchrony in foraging and movement. A large-scale periodic pattern, such as the dark-light cycle of the moon, could thus synchronize migrations across animal populations. However, such cyclic effects on the temporal regulation of migration has not been considered. Here, we show the temporal influence of the lunar cycle on the movement activity and migration tactics in a visual hunting nocturnal insectivore and long-distance migrant, the European nightjar, Caprimulgus europeaus. We found that the daily foraging activity more than doubled during moonlit nights, likely driven by an increase in light-dependent fuelling opportunities. This resulted in a clear cyclicity also in the intensity of migratory movements, with occasionally up to 100% of the birds migrating simultaneously following periods of full moon. We conclude that cyclic influences on migrants can act as an important regulator of the progression of individuals and synchronize pulses of migratory populations, with possible downstream effects on associated communities and ecosystems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa
  • Animal Migration / physiology*
  • Animals
  • Birds / physiology*
  • Ecosystem
  • Energy Intake / physiology
  • Europe
  • Female
  • Food Chain
  • Insecta
  • Male
  • Moon*
  • Periodicity*
  • Photoperiod

Grants and funding

The research received support from the Swedish Research Council (https://www.vr.se/) to AH (621-2012-3585, 2016-03625) and SÅ (621-2013-4361, 2016-05342), and the Centre for Animal Movement Research (CAnMove), financed by a Linnaeus grant (349-2007-8690) from the Swedish Research Council (https://www.vr.se/) and Lund University (https://lunduniversity.lu.se/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.