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

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.

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.

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

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).

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).

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.

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.

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.

Materials and methods

Competition Paired Bird # __________ Eurasian Collared-DoveMourning Dove 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:______________ ______________

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)

Results Interactions Between Eurasian Collared Doves and Mourning Doves Trial #MD DirectMD IndirectMD TotalECD DirectECD IndirectECD Total Total

Results

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.

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.

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.

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.

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

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

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

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.

Questions?