Articles Open access

The “sixth sense” in Scolopacidae (Aves, Charadriiformes): an overview and a photographic collection

Authors

Published
3 June 2026
Section
Articles
DOI
10.4081/rio.2026.950

Abstract

Scolopacidae are characterized by the presence of sensory pits innervated in the central-apical part of the bill, which allow species belonging to this family to locate prey hidden in mud or water with great precision. Although it is known that all Scolopacidae have these pits, the number has been described for only a few species. The authors examined 139 skulls belonging to 25 Palaearctic species (27% of known species) and present a photographic collection of the upper and lower mandibles, in which the sensory pits are clearly visible, their number varying according to species. The lowest number of pits has been recorded in Phalaropus spp., while the highest number has been recorded in Scolopax rusticola. Finally, for comparison, they present photos of the skulls of one species of Recurvirostridae and one of Burhinidae, which also have a modest number of apical pits in the bill.

Keywords

References

  1. Andres K. H. & von Düring M., 1988 – Comparative anatomy of vertebrate electroreceptors. Progress in Brain Research, 74: 113-131. DOI: https://doi.org/10.1016/S0079-6123(08)63006-X
  2. Aradis A., Lo Verde G. & Massa B., 2019 – Importance of millipedes (Diplopoda) in the autumn-winter diet of Scolopax rusticola. European Zoological Journal, 86: 452-457. DOI: https://doi.org/10.1080/24750263.2019.1611955
  3. Bolze G., 1968 – Anordnung und bau der herbstschenkorperchen in limicolenschnabeln imzusammenhang mit nahrungsfindung. Zoologische Anzeiger, 181: 313-355.
  4. Burton P. J. K., 1974 – Feeding and the feeding apparatus in Waders: a study of anatomy and adaptations in the Charadrii. London: British Museum (Natural History).
  5. Collin S.P., 2010. Electroreception in vertebrates and invertebrates. – In: Encyclopedia of animal behavior. Breed M. D. & Moore J. (eds.). Science Direct. DOI: https://doi.org/10.1016/B978-0-08-045337-8.00323-5
  6. Crampton W. G. R., 2019 – Electroreception, electrogenesis and electric signal evolution. Fish Biology, 95: 92-134. DOI: https://doi.org/10.1111/jfb.13922
  7. Cunningham S. J., Alley M. R., Castro I., Potter M. A., Cunningham M. & Pyne M. J., 2010a – Bill morphology of ibises suggests a remote-tactile sensory system for prey detection. Auk, 127: 1-9. DOI: https://doi.org/10.1525/auk.2009.09117
  8. Cunningham S. J., Castro I. & Alley M., 2007 – A new prey-detection mechanism for kiwi (Apteryx spp.) suggests convergent evolution between paleognathous and neognathous birds. Journal of Anatomy, 211: 493-502. DOI: https://doi.org/10.1111/j.1469-7580.2007.00786.x
  9. Cunningham S. J., Castro I., Jensen T. & Potter M. A., 2010b – Remote touch prey-detection by Madagascar crested ibises Lophotibis cristata urschi. Journal of Avian Biology, 41: 350-353. DOI: https://doi.org/10.1111/j.1600-048X.2010.05138.x
  10. Cunningham S. J., Castro I. & Potter M. A. 2009 – The relative importance of olfaction and remote touch in prey detection by North Island brown kiwis. Animal Behavior, 78: 899-905. DOI: https://doi.org/10.1016/j.anbehav.2009.07.015
  11. Cunningham S. J., Corfield J. R., Iwaniuk A. N., Castro I., Alley M. R., Birkhead T. R. & Parsons S. 2013 – The anatomy of the bill tip of Kiwi and associated somatosensory regions of the brain: comparison with shorebirds. PloS One, 8: e80036. DOI: https://doi.org/10.1371/journal.pone.0080036
  12. de Fouw J., van der Heide T., Oudman T., Maas L. R. M., Piersma T. & van Gils J. A., 2016 – Structurally complex sea grass obstructs the sixth sense of a specialized avian molluscivore. Animal Behavior, 115: 55-67. DOI: https://doi.org/10.1016/j.anbehav.2016.02.017
  13. del Hojo J., 2020 – All the birds of the world. Barcelona: Lynx Ed.
  14. du Toit C. J., Chinsamy A. & Cunningham S. J. 2020 – Cretaceous origins of the vibrotactile bill-tip organ in birds. Proceedings Royal Society B, 287: 20202322. DOI: https://doi.org/10.1098/rspb.2020.2322
  15. du Toit C. J., Chinsamy A. & Cunningham S. J., 2022 – Comparative morphology and soft tissue histology of the remote-touch bill-tip organ in three ibis species of differing foraging ecology. Journal of Anatomy, 241: 966-980. DOI: https://doi.org/10.1111/joa.13734
  16. du Toit C. J., Chinsamy A. & Cunningham S. J., 2024 – Good vibrations: remote-tactile foraging success of wading birds is positively affected by the water content of substrates they forage in. Journal of Avian Biology, 2024: e03243. DOI: https://doi.org/10.1111/jav.03243
  17. Gerritsen A. & Meiboom A., 1985 – The role of touch in prey density estimation by Calidris alba. Netherland Journal of Zoology, 36: 530-561. DOI: https://doi.org/10.1163/002829686X00216
  18. Gottschaldt K., 1985 – Structure and function of avian somatosensory receptors. In: Form and function in birds. King A. S. & McLelland J. (eds.). Academic Press. (pp. 375-461).
  19. Gutiérrez-Ibáñez C., Iwaniuk A. N. & Wylie D. R., 2009 – The independent evolution of the enlargement of the principal sensory nucleus of the trigeminal nerve in three different groups of birds. Brain Behaviour Evolution, 74: 280-294. DOI: https://doi.org/10.1159/000270904
  20. Hadley A., 2008 – Combine Z.
  21. Hayman P., Marchant J. & Prater T., 1986 – Shorebirds. An identifcation guide to the waders of the world. London & Sydney: Croom Helm.
  22. Heppleston P. B., 1970 – Anatomical observations on the bill of the Oystercatcher (Haematopus ostralegus occidentalis) in relation to feeding behaviour. Journal of Zoology, 161: 519-524. DOI: https://doi.org/10.1111/j.1469-7998.1970.tb02053.x
  23. Hopkins C. D., 2017 – Electroreception. Encyclopedia Britannica. <https://www.britannica.com/science/electroreception>
  24. Hüttner T., von Fersen L., Miersch L., Czech N. U. & Dehnhardt G., 2022 – Behavioral and anatomical evidence for electroreception in the bottlenose dolphin (Tursiops truncatus). Anatomical Record, 305: 592-608. DOI: https://doi.org/10.1002/ar.24773
  25. Li Q., Jiang P., Li M., Du J., Sun J., Chen N., Wu Y., Chang Q. & Hu C., 2024 – Structure and Phylogenetic Relationships of Scolopacidae Mitogenomes (Charadriiformes: Scolopacidae). Current Issues Molecular Biology, 46: 6186-6198. DOI: https://doi.org/10.3390/cimb46060369
  26. Lin C. T., 2022 – Morphology of the feeding apparatus in shorebirds (Charadriiformes): a comparative analysis. Master of Science in Zoology, Massey University, New Zealand.
  27. Martin G. R., Wilson K. J., Wild J. M., Parsons S., Kubke M. F. & Corfield J., 2007 – Kiwi forego vision in the guidance of their nocturnal activities. PLoS One, 2: e198. DOI: https://doi.org/10.1371/journal.pone.0000198
  28. Mertens J. E. J., Van Roje M., Merckx J. & Dekoninck W., 2017 – The use of low cost compact cameras with focus stacking functionality in entomological digitization projects. Zookeys, 712: 141-154. DOI: https://doi.org/10.3897/zookeys.712.20505
  29. Nebel S., Jackson D. & Elner R., 2005 – Functional association of bill morphology and foraging behaviour in calidrid sandpipers. Animal Biology, 55: 235-243. DOI: https://doi.org/10.1163/1570756054472818
  30. Newton K. C., Bill A. B. & Kajiura S. M., 2019 – Electroreception in marine fishes: chondrichthyans. Fish Biology, 95: 135-154. DOI: https://doi.org/10.1111/jfb.14068
  31. Piersma T., van Aelst R., Kurk K., Berkhoudt H. & Maas L. R. M., 1998 – A new pressure sensory mechanism for prey detection in birds: the use of principles of seabed dynamics? Proceedings Biological Sciences, 265: 1377-1383. DOI: https://doi.org/10.1098/rspb.1998.0445
  32. Prater T., Marchant J. & Vuorinen J., 1977 – Guide to the identification and ageing of holarctic waders. B.T.O. Guide 17, Tring.
  33. Schneider E. R., Gracheva E. O. & Bagriantsev S. N., 2016 – Evolutionary specialization of tactile perception in vertebrates. Physiology, 31: 193-200. DOI: https://doi.org/10.1152/physiol.00036.2015
  34. Whitfield D., 1990 – Individual feeding specializations of wintering turnstone Arenaria interpres. Journal of Animal Ecology, 59: 193-211. DOI: https://doi.org/10.2307/5168
  35. Wilkens L. A. & Hofmann M .H., 2005 – Behavior of animals with passive, low-frequency electrosensory systems. In: Electroreception. Bullock T. H., Hopkins C. D., Popper A. N. & Fay R. R. (eds.). Springer, New York. (21) (pp. 229-263). DOI: https://doi.org/10.1007/0-387-28275-0_9
  36. Zweers G. A. & Gerritsen A. F. C., 1997 – Transitions from pecking to probing mechanisms in waders. Netherland Journal of Zoology, 47: 161-208. DOI: https://doi.org/10.1163/156854297X00166

Metrics

Citations and online attention from Dimensions, Altmetric and PlumX.

PlumX Metrics

License

Copyright (c) 2026 Bruno Massa, Marco Pavia, Arianna Aradis

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

PAGEPress has chosen to apply the Creative Commons Attribution NonCommercial 4.0 International License (CC BY-NC 4.0) to all manuscripts to be published.