Journal of Ornithology

, Volume 160, Issue 1, pp 71–78 | Cite as

Sugar preference of invasive Common Mynas (Sturnus tristis)

  • S. Thobeka GumedeEmail author
  • Colleen T. Downs
Original Article


Nectarivorous and frugivorous birds have been found to select their diet according to sugar type and concentration. Consequently, many studies of sugar preference have been conducted on various avian species. Common Mynas, Sturnus tristis, previously known as Acridotheres tristis, are considered amongst the 100 worst invasive species worldwide and damage fruit crops in some countries. However, their sugar preferences have never been studied. Therefore, we investigated the effect of sugar type and concentration on sugar preference and assimilation efficiency in Common Mynas (n = 7). Birds were given pairwise choice tests of sugars (fructose, sucrose and glucose) of 5 g/ml (5%) to test sugar preference. Common Mynas showed preference for glucose over fructose and sucrose. To determine at which concentrations they prefer glucose, they were offered three different concentrations of glucose (5, 10 and 25%). They showed distinct preference for the 10% concentration of glucose in comparison with 5% and 25% glucose nectars. The birds maintained body mass in the respective experimental trials thus showed sufficient energy intake. Common Mynas failed to digest and absorb sucrose, but fructose and glucose were digested and assimilated efficiently for all concentrations. Results of this study showed that Common Mynas prefer glucose, especially at ~ 10% concentration. Species distribution is determined by food resources, and these results on sugar type and preference of Common Mynas might contribute to preventing or managing their spread in South Africa.


Invasive birds Sugar concentration Assimilation Starling Fructose Glucose 


Zuckerpräferenz beim invasiven Heuschreckenstar ( Sturnus tristis )

Von Vögeln, die sich von Nektar und Früchten ernähren, ist bekannt, dass sie ihre Nahrung nach Art und Konzentration des darin enthaltenen Zuckers auswählen. Für viele Vogelarten liegen bereits entsprechende Untersuchungen zur Zuckerpräferenz vor. Der Heuschreckenstar (Sturnus tristis, früher bekannt als Acridotheres tristis) gilt als eine der „100 schlimmsten invasiven Arten“ weltweit und schädigt Obstplantagen in einigen Ländern. Seine Zuckerpräferenz ist jedoch bislang nie untersucht worden. Deshalb ermittelten wir für Heuschreckenstare (n=7) die Effekte von Zuckertyp und -konzentration auf ihre Zuckerpräferenz und –aufnahmeeffizienz. Den Vögeln wurde die Wahl zwischen Fruktose, Sukrose und Glukose von 5g/ml (5%) gegeben um zu sehen, welchen Zucker sie bevorzugten. Die Heuschreckenstare zogen Glukose der Fruktose und Sukrose vor. Um herauszufinden, bei welcher Konzentration sie Glukose vorzogen, wurde ihnen diese in drei verschiedenen Konzentrationen angeboten: 5%, 10% und 25%, und sie zeigten eine ganz klare Präferenz für die 10%ige Konzentration. In allen drei Varianten dieses Versuchs konnten die Vögel ihre Körpermasse halten, was zeigt, dass ihre Energieaufnahme jeweils ausreichend war. Die Heuschreckenstare waren nicht in der Lage, Sukrose zu verdauen, aber Fruktose und Glukose konnten in allen Konzentrationen effizient verdaut werden. Die Ergebnisse dieser Untersuchung zeigen, dass Heuschreckenstare Glukose bevorzugen, speziell bei Konzentrationen um die 10%. Die Verbreitung einer Art wird vom Vorhandensein von ausreichend Nahrung bestimmt, und unsere Ergebnisse zur Zuckerpräferenz von Heuschreckenstaren könnten einen Beitrag zur Verhinderung oder jedenfalls dem Management ihrer Ausbreitung in Südafrika leisten.



Special thanks are due to the University of KwaZulu-Natal, the National Research Foundation, and the Centre of Excellence for Invasion Biology, University of Stellenbosch, for research funding. We thank T. Mjwara for helping in the animal house, and E. Ally and P. Singh for helping in the field. We are grateful to B. Jilajila for his support and advice. We are grateful for the constructive comments of the reviewers.

Compliance with ethical standards

Conflict of interest

The authors declare they have no competing interests.

Ethical standards

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. We had permission for the study from the University of KwaZulu-Natal Animal Research Ethics Committee.


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Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2018

Authors and Affiliations

  1. 1.DST-NRF Center for Invasion Biology, School of Life SciencesUniversity of KwaZulu-NatalPietermaritzburgSouth Africa

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