, Volume 184, Issue 1, pp 183–192 | Cite as

Effective nut dispersal by magpies (Pica pica L.) in a Mediterranean agroecosystem

  • Jorge Castro
  • Mercedes Molina-Morales
  • Alexandro B. Leverkus
  • Loreto Martínez-Baroja
  • Lorenzo Pérez-Camacho
  • Pedro Villar-Salvador
  • Salvador Rebollo
  • José M. Rey-Benayas
Plant-microbe-animal interactions - original research


Scatter-hoarding animals such as corvids play a crucial role in the dispersal of nut-producing tree species. This interaction is well known for some corvids, but remains elusive for other species such as the magpie (Pica pica), an abundant corvid in agroecosystems and open landscapes of the Palearctic region. In addition, the establishment of the individual dispersed seeds—a prerequisite for determining seed-dispersal effectiveness—has never before been documented for the interaction between corvids and nut-producing trees. We analyzed walnut dispersal by magpies in an agroecosystem in southern Spain. We used several complementary approaches, including video recording nut removal from feeders, measuring dispersal distance using radio tracking (with radio transmitters placed inside nuts), and monitoring the fate of dispersed nuts to the time of seedling emergence. Magpies were shown to be highly active nut dispersers. The dispersal distance averaged 39.6 ± 4.5 m and ranged from 4.1 to 158.5 m. Some 90% of the removed walnuts were cached later, and most of these (98%) were buried in the soil or hidden under plant material. By the time of seedling emergence, ca. 33% of nuts remained at the caching location. Finally, 12% of the cached nuts germinated and 4% yielded an emerged seedling, facilitating the transition to the next regeneration stage. The results demonstrate for the first time that magpies can be an effective scatter-hoarding disperser of a nut-producing tree species, suggesting that this bird species may play a key role in the regeneration and expansion of broadleaf forests in Eurasia.


Corvidae Forest regeneration Juglans Radio tracking Scatter-hoarding Seed caching Seed dispersal effectiveness 



This study was supported by the projects CGL2014-53308-P of the Spanish Government and Remedinal 3 (S2013/MAE-2719) of the Madrid Government. The Consejería de Medio Ambiente (Junta de Andalucía) provided fieldwork permission. LMB was supported by a FPI scholarship (BES-2015-075276) from the Spanish Government. AL acknowledges support from the University of Granada and Project GEI Spain (CGL2014-52838-C2-1-R) funded by the Spanish Ministerio de Economía y Competitividad, including European Union ERDF funds. We thank Dr. E.W. Schupp and two anonymous reviewers for providing suggestions that enhanced the manuscript.

Author contribution statement

JC, LPC, PVS, SR, and JMRB conceived and designed the experiments. JC, MMM, AL, and LMB performed the field work. JC, MMM, and AL performed statistical analyses. JC wrote the first draft of the manuscript; all authors provided editorial advice.

Supplementary material

442_2017_3848_MOESM1_ESM.pdf (886 kb)
Figure S1. Characteristics of the feeders used in this study. The first feeder (feeder 1 in Fig. 1 of the manuscript) consisted of an almost flat roof of a chicken house placed 2.20 m above the ground plus a wooden slat that prevented the nuts from rolling down (upper picture). The second feeder (feeder 2 in Fig. 1 of the manuscript) was a 30 × 40 cm wooden cage with a metal bottom, held 1.7 m from the ground by a metal post and located below the canopy of a walnut tree (bottom picture). We knew from previous observations that magpies foraged or perched regularly in both locations. The two feeders were placed 100 m from each other. Figure S2. Details of radio transmitter insertion into a walnut. The nut was split open with a knife, a portion of the kernel similar in weight to the transmitter was removed, the transmitter was inserted into the nut with the antenna rolled, and finally the two halves of the shell were glued together with superglue (Loctite®). (PDF 886 kb)
442_2017_3848_MOESM2_ESM.doc (149.1 mb)
Video recording with a movement-sensitive camera in feeder 1 on 27 October 2015, showing three magpies at once, with two of them retrieving a nut each (containing transmitters in this case). The time that appears in the video is the local time, one hour ahead of solar time (thus, it was 8 am solar time). It can be observed that the second magpie that removed a nut flew westwards beyond a group of trees, where it was lost at a distance of ca. 130 m from the feeder. This transmitter was not found despite a thorough search at distances of up to 300 m, and may represent a long-distance dispersal event. (DOC 152722 kb)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Jorge Castro
    • 1
  • Mercedes Molina-Morales
    • 2
  • Alexandro B. Leverkus
    • 1
    • 3
  • Loreto Martínez-Baroja
    • 3
  • Lorenzo Pérez-Camacho
    • 3
  • Pedro Villar-Salvador
    • 3
  • Salvador Rebollo
    • 3
  • José M. Rey-Benayas
    • 3
  1. 1.Departamento de Ecología, Facultad de CienciasUniversidad de GranadaGranadaSpain
  2. 2.Departamento de Zoología, Facultad de CienciasUniversidad de GranadaGranadaSpain
  3. 3.Grupo de Investigación “Ecología y Restauración Forestal” FORECO, Departamento de Ciencias de la Vida, UD Ecología, Edificio de CienciasUniversidad de AlcaláAlcalá De HenaresSpain

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