Day and night use of habitats by northern pintails during winter in a primary rice-growing region of Iberia

PLoS One. 2019 Jul 25;14(7):e0220400. doi: 10.1371/journal.pone.0220400. eCollection 2019.

Abstract

Loss of natural wetlands is a global phenomenon that has severe consequences for waterbird populations and their associated ecosystem services. Although agroecosystems can reduce the impact of natural habitat loss, drivers of use of such artificial habitats by waterbirds remain poorly understood. Using the cosmopolitan northern pintail Anas acuta as a model species, we monitored home-range and fine-scale resource selection across the agricultural landscape. Individuals were tracked using GPS-GSM transmitters, and a suite of environmental and landscape features were measured throughout the winter seasons. Spatial patterns of habitat use were analysed using generalized linear mixed effect models by integrating field-observations with GPS telemetry. All birds used rice fields as foraging grounds at night and commuted to an adjacent reservoir to roost during daylight. Home-ranges and maximum foraging distances of nocturnally foraging birds increased with decreasing availability of flooded fields, and were positively correlated with moonlight levels. Birds selected flooded rice paddies (water depth range: 9-21 cm) with standing stubble and substrate with pebbles smaller than 0.5 cm in diameter. Density of rice seeds, rice paddy size, and other environmental and landscape features did not emerge as significant predictors. Our findings indicate that nocturnal foraging of northern pintails within rice fields is driven primarily by straw manipulation, water level and substrate pebble size. Thus, the presence of standing stubble in flooded paddies with soft bottoms should be prioritized to improve foraging areas for dabbling ducks. These management procedures in themselves would not increase economic costs or affect rice production and could be applied for dabbling-duck conservation throughout the world.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agriculture* / methods
  • Animal Migration / physiology
  • Animals
  • Anseriformes / physiology*
  • Behavior, Animal
  • Circadian Rhythm / physiology*
  • Ecosystem*
  • Floods
  • Oryza / growth & development
  • Rivers
  • Seasons
  • Spain
  • Wetlands*

Grants and funding

JAM received the project PRI09C128 (Junta de Extremadura), http://ayudaspri.gobex.es. JMSG received the project GR18169 (Government of Extremadura and the European Regional Development Fund [ERDF]), http://cicytex.juntaex.es. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.