Opportunism and cognition in birds Lima Kayello Department of Biology McGill University Montréal, QC, Canada Submitted April 2013 A thesis submitted to McGill University in partial fulfillment of the requirements of the degree of Master of Science © Lima Kayello 2013 ACKNOWLEDGEMENTS I would like to thank my M.Sc. supervisor, Louis Lefebvre, for his relentless support, encouragement and enthusiasm throughout my candidacy. He has helped me grow as a researcher, and more so as a critical and analytical thinker. With his guidance and reinforcement, I was able to professionally develop my oral and written communication skills. Louis, with his love for telling stories through a still frame, has also inspired me to participate in projects outside my academic/work life and make time for things I enjoy. I am very grateful to the members of the Lefebvre lab, Jean-Nicolas Audet and Simon Ducatez for their contributions in the field and the laboratory, as well as their aid in data collection and analysis. I thank my supervisory committee members, Dr. David Bird and Dr. Andrew Hendry, for their helpful comments throughout the progress of my thesis. Special thanks to Dr. Bird and his team at the Faculty of Agricultural and Environmental Sciences for their help with field advice and equipment. I have gained a tremendous amount of practice and experience netting, extracting and banding birds at the McGill Bird Observatory with the guidance and supervision of an amazing group of professional birders and volunteers. Getting into this project, I had no experience with bird research and conservation, let alone catching, handling and banding any animal. Therefore, I am extremely grateful to Gay McDougall Gruner, Simon Duval and Marcel Gahbauer for their field advice. Special thanks to Gay and Simon for sharing extremely helpful fielding practice and for teaching me the proper techniques of mist netting, bird banding and handling. Their undying love and dedication towards bird monitoring and conservation is ever so contagious, and I have been bitten by the bird love-bug ever since. Blandine Doligez and Laure Cauchard, thank you for your patience and field advice, and for guiding me through the initial stages of my field season in Barbados. Frank Cézilly, the Cézilly lab and Melanie Couture, thank you for your volunteered time and efforts in support of the project. I would also like to express my gratitude towards the staff of the Bellairs Research Institute for their help throughout this study. This work could not have been done without the financial support provided by Natural Sciences and 2 Engineering Research Council (NSERC Canada) graduate scholarship to LK and NSERC Discovery Grant to LL. Last but not least, a special thank you to my mother, Huda Al Zaben, my brother, Rami Kayello, and my boyfriend, Taha Zein, for believing in me and encouraging me to strive to for the best in all aspects of life. 3 ABSTRACT Animals vary in their response to the distribution of resources in time and space. Opportunistic foraging is evident in many species and has indirectly been shown to be linked to measures of cognition such as innovation and problem solving. However, in the field of cognitive ecology, the operationalization and empirical use of opportunism is problematic. In chapter 1, I review the concept of opportunism in the zoological literature and propose an operational definition. The review suggests that many definitions of the concept are not useful, in particular those that equate it with generalism or use it to describe random choice in foraging. With the operational definition I propose ('latency to switch to a new, abundant, food source'), the relationship between ecological flexibility and cognition is then addressed through a small-scale comparative study in chapter 2. Here, the purpose is to determine if an opportunistic species will perform better at problem solving, and have lower neophobic tendencies, than a less opportunistic species. The study compares two sister species of Thraupidae with different foraging strategies: the Barbados bullfinch (Loxigilla barbadensis), an opportunistic forager, and the black-faced grassquit (Tiaris bicolor), a conservative forager. In the field, I carried out focal observations along with opportunism and neophobia experiments. In captivity, wild-caught individuals were run through a set of behavioural and cognitive tests, which included a neophobia test and a problem-solving obstacle removal task. Results show that although both species share overlapping foraging modes, territorial habits and neophobic tendencies, the Barbados bullfinch is much more opportunistic, bolder and better at problem-solving than the black-faced grassquit. 4 RÉSUMÉ Les animaux diffèrent dans leurs réponses à la distribution spatiale et temporelle des ressources. Plusieurs espèces manifestent un mode opportuniste de quête alimentaire et des preuves indirectes suggèrent que l'opportunisme est associé à des mesures de cognition telles que l'innovation et la résolution de problèmes. Toutefois, dans le domaine de l'écologie cognitive, la définition et l'opérationalisation de l'opportunisme pose problème. Dans le premier chapitre de ce mémoire, je fais une revue de littérature du concept d'opportunisme et j'en propose une définition opérationelle. La revue suggère que plusieurs acceptions du concept sont peu utiles, en particulier celles qui le confondent avec le concept de 'genéralisme' et celles qui lui donnent le sens de 'capture au hasard' de proies. A partir de la définition opérationelle que je propose ('la latence d'exploitation d'une nouvelle et abondate source de nourriture'), la relation entre l'opportunisme et la cognition est testée au chapitre 2 dans une étude comparative à petite échelle. Je prédis qu'une espèce opportuniste sera plus rapide à résoudre un problème alimentaire et sera moins néophobe qu'une espèce conservatrice. L'étude compare deux espèces génétiquement très proches, le sporophile de la Barbade (Loxigilla barbadensis), une espèce opportuniste, et le sporophile cici (Tiaris bicolor), une espèce conservatrice. J'ai effectué sur le terrain des observations focales et des expériences sur l'opportunsime et la néophobie. En captivité, j'ai soumis des individus piégés sur le terrain à des tests de néophobie et d'enlèvement d'obstacle pour atteindre de la nourriture. Les résultats révèlent que le sporophile de la Barbade est plus opportuniste, moins néophobe et meilleur à résoudre le problème que le sporophile cici, mais que ni sa territorialité ni son mode d'alimentation sur le terrain ne diffèrent suffisamment de celui du sporophile cici pour expliquer les différences de cognition. 5 TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................ 2 ABSTRACT ..................................................................................................................... 4 RÉSUMÉ .......................................................................................................................... 5 TABLE OF CONTENTS ................................................................................................ 6 LIST OF TABLES ........................................................................................................... 8 LIST OF FIGURES ......................................................................................................... 9 THESIS FORMAT ........................................................................................................ 13 CONTRIBUTIONS OF CO-AUTHORS ..................................................................... 13 GENERAL INTRODUCTION ..................................................................................... 14 CHAPTER 1: Opportunism and its relation to generalism and other ecological determinants of cognition................................................................................................. 15 Abstract ..................................................................................................................... 16 1. Ecological correlates of cognition ..................................................................... 17 a. Environmental variables .......................................................................... 17 b. Animal traits that vary with environmental variables ............................. 19 2. Opportunism and generalism ........................................................................... 21 a. Are they the same thing? ......................................................................... 21 b. The many uses of the term ‘opportunism’: a review ............................... 23 c. Quantifying opportunism and generalism ............................................... 26 d. The operational definition used in this thesis .......................................... 30 Acknowledgements .................................................................................................. 31 References ................................................................................................................. 31 Tables ........................................................................................................................ 44 6 Connecting statement .............................................................................................. 49 CHAPTER 2: Opportunism, Neophobia and Problem-solving in Sister Taxa from the Family Thraupidae, the Barbados Bullfinch Loxigilla barbadensis and the Black-faced