Effects of conspecific behavior and refuge complexity on anti-predator decision making

1. Effects of conspecific behavior and refuge complexity on anti-predator decision making Author: Elizabeth Tran Mentor: Dr. Esteban Fernández-Juricic Affiliation: CSULB

2. Outline • Introduction • Materials and methods • Expected results • Conclusion • Future experiments

3. Introduction • House Finch (Carpodacus mexicanus)

4. Introduction • Geographic range • Abundant bird often associated closely with human habitation. • Habitat • Native western population occurs in a wide variety of habitats ranging from undisturbed desert to chaparral and open coniferous forests to cities • Prefers edge habitat, and even in desert areas, these finches require a source of water, as well as structures for perching and nesting

5. Why House Finches? Abundance Easy to handle Good model for predator-prey interaction Why a raptor? Good predator in the wild A convincing predator Natural predator of House Finches along with cats and snakes Introduction

6. Introduction • Current Understanding • Studies of lizards • Thermal Cost • Reaction to predator • Repeated attacks • Tradeoffs • Reaction of bird to Predator • Before and after response • No studies have been performed that show prey reaction of birds in a refuge after an attack

7. Introduction • What will I do? • Determine the • scanning (duration and rate) • intake rate • feeding time • handling time • foraging efficiency • recovery time • searching time (duration and rate) • time in refuge (3 levels) • time in link • moving rate in link • moving rate in refuge

8. Introduction • Hypothesis • Focal animal with conspecific foraging will also forage without scanning • Flock with animal foraging will perceive that there is no predator • Focal animal with conspecific scanning will also scan while foraging • Scanning means that there are predators nearby • Focal animal in refuge with low foliage will return to foraging faster • Not enough cover has higher cost than staying in refuge

9. Materials and methods • Animal collection/sample size • House Finches will be caught by OCVC staff under its license • 90 adult individuals from local populations (similar proportion of males and females)

10. Materials and methods • Animal care • Feeding (water and sunflower seeds with variety of other seeds) • Placed in Animal Facilities with constant air temperature • Infection control • Removal of bedding daily • Animal that contain certain disease (West Nile Virus) will be remove from the population

11. Materials and methods • Treatments and general procedures • All House Finches are tagged • Animals will be housed in groups and will undergo the experimental conditions only once • Experiment will be conducted during the non-breeding season • Food deprivation period

12. Materials and methods

13. Materials and methods • 2 manipulations • Conspecific behaviors • 3 levels • control with no conspecifics, • conspecifics foraging, • conspecifics scanning • Foliage • 2 levels • low • high

14. Materials and methods • Statistical analyses • Statistica Software • Factorial ANCOVA • To determine if there is a significant difference in refuge usage in each manipulation (social condition, cage condition, etc.) • Determine the recovery time for each manipulation

15. Expected results Table 1. Variables recorded from each experiment. (Similar table to Creswell, Quinn, Whittingham, & Butler, 2003) (Standard variables are in bold and were in all initial models.)

16. Expected results Figure 2. The speed of House Finches response to an approaching model sparrow hawk was dependent on the head-up rate. The graph illustrates residual transformed response time (controlling for position of the House Finches, model speed, trial number and body condition) with head-up rate. (Similar graph to Creswell, Quinn, Whittingham, & Butler, 2003)

17. Expected results Figure 3. Head-up rate was dependent on the peck rate. Non-significant variables removed from the model were, sex, response type, trial number and body condition. (Similar graph to Creswell, Quinn, Whittingham, & Butler, 2003)

18. Expected results High Refuge patch foliage Low Time spent in refuge Figure 4. The time House Finches spend in the refuge corresponded to the amount of foliage of the refuge depending on the attack condition of the predator and trade-off.

19. The predation risk forces the animals to use anti-predator behaviors having increased associated cost Increasing time spent in the refuge Increase time spent scanning The emergence from refuge increases when the amount of food availability was high and when the predator’s attack was unsuccessful Conclusion

20. Future experiment • Understand mechanism where focal animal make use of refuge and patch exploitation

21. Acknowledgements • Dr. Esteban Fernández-Juricic • Dr. Robert Cummings (Orange County Vector Control ) • Dr. Mason • Howard Huges Medical Institute • Nima Gilak