Journal of Ornithology

, Volume 156, Supplement 1, pp 163–172

Proximate mechanisms of detecting nut properties in a wild population of Mexican Jays (Aphelocoma ultramarina)

  • Piotr G. Jablonski
  • Sang-im Lee
  • Elzbieta Fuszara
  • Maciej Fuszara
  • Choongwon Jeong
  • Won Young Lee

DOI: 10.1007/s10336-015-1193-6

Cite this article as:
Jablonski, P.G., Lee, S., Fuszara, E. et al. J Ornithol (2015) 156(Suppl 1): 163. doi:10.1007/s10336-015-1193-6


In contrast to extensive research on optimal foraging in birds, the proximate mechanisms by which birds estimate the properties of nuts or seeds have not been well studied. Using slow-motion video-recording and experiments with modified peanuts presented to birds in their natural habitat, we explored these issues in a wild population of the Mexican Jay (Aphelocoma ultramarina). Jays evaluated each peanut by performing fast movements of the head combined with additional fast movements of the beak, which may open and subsequently close producing sound at the moment of hitting the shell. These movements seemed to provide Jays with additional sensory information that led to a more strict discrimination against non-preferred peanuts. We presented Jays with two types of peanuts that looked similar but differed in weight and found that, after handling the nuts, Jays consistently preferred the heavier nuts. In another experiment, the visually larger nuts with atypically lower mass (due to experimental alteration) were picked up easily but subsequently were rejected during handling, while the smaller peanuts with the weight typical for the size were easily accepted leading to the preferences for nuts with higher nutmeat density. This indicates that birds may have a concept of how much a nut of a given size should weigh, or alternatively that simple correlation between density of nut content and the properties of sound produced during handling lead to the ability of choosing denser nuts. We discuss further experimental studies that may bring more understanding of the proximate mechanisms of nut content assessment by birds.


Mexican Jay Corvidae Heaviness Proximate mechanisms Nuts Foraging Food preferences 

Supplementary material

10336_2015_1193_MOESM1_ESM.docx (638 kb)
Supplementary material 1 (DOCX 638 kb)
10336_2015_1193_MOESM2_ESM.mpg (12.1 mb)
Supplementary material 2 (MPG 12432 kb)
10336_2015_1193_MOESM3_ESM.mpg (12.1 mb)
Supplementary material 3 (MPG 12373 kb)
10336_2015_1193_MOESM4_ESM.mpg (16 mb)
Supplementary material 4 (MPG 16406 kb)
10336_2015_1193_MOESM5_ESM.mpg (18.5 mb)
Supplementary material 5 (MPG 18968 kb)
10336_2015_1193_MOESM6_ESM.mpg (29.7 mb)
Supplementary material 6 (MPG 30386 kb)
10336_2015_1193_MOESM7_ESM.mpg (25.3 mb)
Supplementary material 7 (MPG 25856 kb)

Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2015

Authors and Affiliations

  • Piotr G. Jablonski
    • 1
    • 2
  • Sang-im Lee
    • 1
    • 3
  • Elzbieta Fuszara
    • 4
  • Maciej Fuszara
    • 5
  • Choongwon Jeong
    • 1
    • 6
  • Won Young Lee
    • 1
    • 7
  1. 1.Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, College of Natural SciencesSeoul National UniversitySeoulRepublic of Korea
  2. 2.Museum and Institute of EcologyPolish Academy of SciencesWarsawPoland
  3. 3.Institute of Advanced Machinery and DesignSeoul National UniversitySeoulRepublic of Korea
  4. 4.Faculty of Biology, Department of Animal PhysiologyUniversity of WarsawWarsawPoland
  5. 5.Faculty of Biology and Environmental SciencesCardinal Stefan Wyszynski UniversityWarsawPoland
  6. 6.Department of Human Genetics, CLSCUniversity of ChicagoChicagoUSA
  7. 7.Division of Polar Life SciencesKorea Polar Research InstituteIncheonRepublic of Korea

Personalised recommendations