Journal of Ornithology

, Volume 156, Supplement 1, pp 163–172 | Cite as

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

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


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 



We thank Esther and Jerram Brown for introducing us to the Mexican Jays many years ago and for letting us to take over the research on their population in the Chiricahua Mountains, as well as for motivating us to continue research on those elegant birds. We thank Dr. Dawn Wilson, the director of the Southwestern Research Station (SWRS), and the staff at the SWRS, for their logistic and administrative support during our research. We thank Nahyun Sung for help in the field work. We also thank Soorim Song, Moon Jong Yeol, and Kyuwoong Kim for analyzing the videos. P.G.J. thanks Janusz Uchmanski at the Centre for Ecologial Research of the Polish Academy of Sciences, and Wieslaw Bogdanowicz at the Institute and Museum of Zoology, Polish Academy of Sciences, for helping in this study’s logistics. Main funding was provided by the Polish Ministry of Education and the Polish National Science Center (grant No. ODW-1384/B/P01/2011/40; application No. N N304 138440); additional funding was provided by the National Research Foundation of Korea (grant no. 2014-048162).

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  1. Amazeen EL, Turvey M (1996) Weight perception and the haptic size-weight illusion are functions of the inertia tensor. J Exp Psychol Hum Percept Perform 22:213–232PubMedCrossRefGoogle Scholar
  2. Bossema I (1979) Jays and oaks: an eco-ethological study of a symbiosis. Behavior 70:1–117CrossRefGoogle Scholar
  3. Brown JL (1970) Cooperative breeding and altruistic behavior in the Mexican jay, Aphelocoma ultramarina. Anim Behav 18:366–378CrossRefGoogle Scholar
  4. Brown JL (1972) Comunal feeding of nestlings in jays—a theory for the evolution of altruism and communal breeding. Am Zool 14:63–80CrossRefGoogle Scholar
  5. Brown JL, Li SH, Bhagabati N (1999) Long-term trend toward earlier breeding in an American bird: a response to global warming? Proc Natl Acad Sci USA 96:5565–5569PubMedPubMedCentralCrossRefGoogle Scholar
  6. Carello C, Turvey M (2004) Physics and psychology of the muscle sense. Curr Dir Psychol Sci 13:25–28CrossRefGoogle Scholar
  7. Carello C, Santana MV, Burton G (1996) Selective perception by dynamic touch. Percept Psychophys 58:1177–1190PubMedCrossRefGoogle Scholar
  8. Crawford CB (1993) The future of sociobiology: counting babies or studying proximate mechanisms. 8:183–186PubMedCrossRefGoogle Scholar
  9. Dixon MD, Johnson W, Adkisson CS (1997) Effects of weevil larvae on acorn use by blue jays. Oecologia 111:201–208CrossRefGoogle Scholar
  10. Emery NJ, Clayton NS (2004) The mentality of crows: convergent evolution of intelligence in Corvids and Apes. Science 306:1903–1907PubMedCrossRefGoogle Scholar
  11. Greig-Smith PW, Crocker DR (1986) Mechanisms of food selection by bullfinches (Pyrrhulla pyrrhula L.) feeding on sunflower seeds. Anim Behav 34:843–859CrossRefGoogle Scholar
  12. Heinrich B, Joerg CC, Madden SS, Sanders EW (1997) Black-capped chickadees and red-breasted nuthatches “weigh” sunflower seeds. Auk 114:298–299CrossRefGoogle Scholar
  13. Hubbard JA, McPherson GR (1997) Acorn selection by Mexican jays: a test of a tritrophic symbiotic relationship hypothesis. Oecologia 110:143–146CrossRefGoogle Scholar
  14. Johnson KO (2001) The roles and functions of cutaneous mechanoreceptors. Curr Opin Neurobiol 11:455–461PubMedCrossRefGoogle Scholar
  15. Johnson WC, Adkisson CS (1986) Airlifting the oaks. Nat Hist 10:40–47Google Scholar
  16. Johnson LS, Marzluff JM, Balda RP (1987) Handling of pinyon pine seed by the Clark’s Nutcracker. Condor 89:117–125CrossRefGoogle Scholar
  17. Johnson WC, Thomas L, Adkisson CS (1993) Dietary circumvention of acorn tannins by blue jays: implications for oak demography. Oecologia 94:159–164CrossRefGoogle Scholar
  18. Jones LA (1986) Perception of force and weight: theory and research. Psychol Bull 100:29–42PubMedCrossRefGoogle Scholar
  19. Krebs JR, Davies NB (1978) Behavioural ecology: and evolutionary approach. Blackwell, OxfordGoogle Scholar
  20. Langen T (1999) How western scrub jays select a nut. Anim Cogn 2:223–233CrossRefGoogle Scholar
  21. Langen TA, Gibson RM (1998) Sampling and information acquisition by western scrub jays. Anim Behav 55:1245–1254CrossRefGoogle Scholar
  22. Ligon JD, Martin DJ (1974) Pinyon seed assessment by the pinyon jay (Gymnorhinus cyanocephalus). Anim Behav 22:421–429CrossRefGoogle Scholar
  23. Lutbeg B, Langen TA (2004) Comparing alternative models to empirical data: cognititve models of western scrub jay foraging behavior. Am Nat 163:263–276CrossRefGoogle Scholar
  24. Moore JE, Swihart RK (2006) Nut selection by captive Blue jays: importance of availability and implications for seed dispersal. Condor 108:377–388CrossRefGoogle Scholar
  25. Pons J, Pausas JG (2007) Not only size matters: acorn selection by the European jay. Acta Oecol 31:353–360CrossRefGoogle Scholar
  26. Preston SD, Jacobs LF (2009) Mechanisms of cache decision making in fox squirrels (Sciurus niger). J Mammal 90:787–795CrossRefGoogle Scholar
  27. Scarlet TL, Smith KG (1991) Acorn preference of urban blue jays during fall and spring in northwestern Arkansas. Condor 93:438–442CrossRefGoogle Scholar
  28. Stamps JA (1991) Why evolutionary issues are reviving interest in proximate behavioral mechanisms. Am Zool 31:338–348CrossRefGoogle Scholar
  29. Stephens DW, Krebs JR (1986) Foraging theory. Princeton University Press, PrincetonGoogle Scholar
  30. Stephens DW, Brown JS, Ydenberg YC (2007) Foraging: behavior and ecology. University of Chicago Press, ChicagoCrossRefGoogle Scholar
  31. Turvey MT (1996) Dynamic touch. Am Psychol 51:1134PubMedCrossRefGoogle Scholar
  32. Visalberghi E, Neel C (2003) Tufted Capuchins (Cebus paella) use weight and sound to choose between full and empty nuts. Ecol Psychol 15:215–228CrossRefGoogle Scholar

Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2015

Authors and Affiliations

  • Piotr G. Jablonski
    • 1
    • 2
  • Sang-im Lee
    • 1
    • 3
    Email author
  • 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

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