Competition between mourning Doves and Eurasian collared doves

1. Competition between mourning Doves and Eurasian collared doves A research project conducted by Philip Earhart Undergraduate Student Tennessee Technological University Cookeville, TN 38505

2. Project summary • During this project I attemped to determine whether or not exotic Eurasian Collared doves are capable of out-competing native Mourning doves for food resources. • Collared doves are a non-native species that could potentially displace the native Mourning doves. • The collared doves are much larger than the Mourning doves which would seem to offer them a distinct advantage when forced to compete for food resources.

3. Project summary • I tried to determine if competition between these two species existed and to what degree it occurred. • I conducted this study by allowing these two species to interact in a controlled setting and recording the results of the study. • I expected that there will be a certain level of competition between the two species of birds.

4. Introduction • Pair of native Mourning doves shown Fig. 1 left Fig. 1 • Pair of exotic Eurasian Collared doves shown Fig. 2 right Fig. 2

5. Introduction • Mourning doves are one of the most important game birds in the U.S. today (Hayslette 2001). • 2.4 million Mourning dove hunters harvested 46 million birds each year during the 1980’s (Romagosa 2000). • Eurasian Collared doves are becoming increasingly more prevalent in the U.S. and causing a significant impact on the natural ecosystems (Stedman 1998). • Mourning dove populations declined drastically around Cedar Key, Florida after the arrival of Collared doves (Stedman 1998).

6. Introduction • Collared doves are native to India and Sri Lanka (Romagosa 1999). • Collared doves seem to be more aggressive than Mourning doves and have also been seen chasing other species of native song birds away from feeder stations (Romagosa 2000). • The introduction of Collared doves has the potential to displace native doves as well as the potential of disease introduction (Romagosa 2000).

7. hypothesis • My hypothesis for the project is that the Eurasian Collared Doves will out compete the Mourning Doves because of the size advantage they possess. • Collared Doves are physically larger and therefore will be able to force Mourning Doves away from food sources and keep them away. • My objective is to determine whether or not the exotic species is placing pressure on the native species and estimate the effects may have on the natural ecosystem.

8. Materials and methods • Both Mourning doves and Collared doves were trapped from areas where they existed together. • The birds were then transferred to a holding facility on the TN Tech campus for observations. • Birds were fed and watered ad libitum prior to competition studies. • Prior to competition studies birds were fasted for 12 hours, but were allowed access to fresh water at all times.

9. Materials and methods

10. Materials and methods • A 0.45 m x 0.45 m x 3 cm feeding tray with 6 different types of seeds and grains was then placed in the aviary containing both a Mourning dove and a Collared dove. • Observations were taken for the next 30 minutes from a location hidden from the birds. • Interactions between the birds were tabulated from the viewing point and classified as direct, physical contact between the birds, and indirect, looking and chasing.

11. Materials and methods

12. Materials and methods Competition Paired Bird # __________ Eurasian Collared-Dove Mourning Dove Band Number ____________ Band Number ____________ Mass __________________ Mass ___________________ Mass Difference_________________ Single Patch Trial Date ________ Time Start ________ Temp Start ______ Weather Start _________ Time End _________ Temp End ______ Weather End __________ Interactions Between Species Number of Interactions ECD directly displaces MD (touch) ______________________________ ECD indirectly displaces MD (chase) ____________________________ ECD indirectly displaces MD (look) ______________________________ MD directly displaces ECD (touch) ______________________________ MD indirectly displaces ECD (chase) ____________________________ MD indirectly displaces ECD (look) ______________________________ Total Interactions ___________________________________________ Comments: ________ ______ ________ ______ ________ ______

13. Materials and methods • A total of 6 trials were performed in an attempt to prevent distortion of the data results. • The setup for the trials was modeled after a combination of several researchers. (Brown 1998; Hayslette and Mirarchi 2002)

14. Results

15. Results

16. Discussion • The Two Species of Birds Definitely Displayed a level of Competition between themselves. • Both Mourning doves and Collared doves competed with one another for food. • Interactions seemed to be on an individual-to-individual basis rather than a species-to-species basis as hypothesized.

17. Discussion • The birds may not have competed as heavily for food at this time of year since it is not as tough as it may become. • Competitions may increase during the mating season. • More research is needed to determine what effects the exotic Eurasian Collared dove may be having on already declining native Mourning dove populations.

18. Conclusion • I concluded that my hypothesis was invalid because the Collared doves did not out-compete Mourning doves for food. • Mourning doves were actually more aggressive than Collared doves during the study.

19. Conclusion • Although there are definitely interactions and competition between these two species of doves, the Eurasian collared dove does not seem to be physically out-competing the Mourning dove for food resources.

20. Literature cited • Brown, J.S. 1988. Patch Use as an Indicator of Habitat Preference, Predation Risk, and Competition. Behavioral Ecology and Sociology.22: 37-47. • Hayslette, S.E. and R.E. Mirarchi. 2001. Patterns of Food Preferences in Mourning Doves. Journal of Wildlife Management. 65: 816-827. • Hayslette, S.E. and R.E. Mirarchi. 2002. Foraging-Patch Use and Within-Patch Diet Selectivity in Mourning Doves, Zenaida macroura. Journal of Wildlife Management. 83 (9): 2637-2641. • Hengeveld, R. 1993. What to do about the North American Invasion by the Collared Dove. Journal of Field Ornithology. 64 (4): 477-489.

21. Literature cited • Loeb, S.C. and Hooper, R.G. 1997. An Experimental Test of Interspecific Competition for Red-Cockaded Woodpecker Cavities. Journal of Wildlife Management. 61 (4): 1268-1280. • Reed, D.F. 2001. A Conceptual Interference Competition Model for Introduced Mountain Goats. Journal of Wildlife Management. 65 (1): 125-128. • Romagosa, C.M. 2002. Eurasian Collared-Dove. The Birds of North America. 629: 1-20. • Romagosa, C.M. and Labisky, R.F. 2000. Establishment and Dispersal of the Eurasian Collared-Dove in Florida. Journal of Field Ornithology. 71 (1): 159-166.

22. Literature cited • Romagosa, C.M. and McEneaney, T. 1999. Eurasian Collared-Dove in North America and the Caribbean. North American Birds. 53 (4): 348-353. • Stedman, S.J. 1998. Changing Seasons: The Nesting Season. North American Birds. 52 (4): 424-426. • Tomlinson, R.E. et al. 1994. Mourning Dove. Migratory Shore and Upland Game Bird Management in North America. 47 (3): 5-26.

23. Acknowledgements • I would like to thank Trisha Poling for all of her help with this project as well as the Tennessee Wildlife Resources Agency and Tennessee Technological University for financial support.

24. Questions?