Skip to main content Cornell University NBB
more options


thumbnail imagethumbnail imagethumbnail image

Charles Walcott

Professor Emeritus

W255 Seeley G. Mudd Hall
Cornell University
Ithaca, NY 14853

Phone: (607) 254-4382
Fax: (607) 254-1303

Research Interests

Male Common Loons, Gavia immer, produce a territorial vocalization called the "yodel". Using a banded population of Loons, we have been analyzing tape recorded yodels to measure in which ways the yodels differ between males and how consistent these variations are from year to year. We have developed a statistical model that allows us to recognize an individual male within the population. Yodels differ greatly between loon populations and there is a general geographic trend as well. We have recently found that while an individual males yodel is stable year after year on the same territory, of the sixteen occasions when the male loon changed territory, on thirteen of these it changed its yodel. The change doesn’t seem to be related to the change in female because when the female changes, it has no effect on the male’s yodel. Nor does it seem to be related to the yodels of loons in neighboring lakes; the change in yodel was just as likely to make it similar to that of the neighbor as it was to increase the difference. Surprisingly, in the ten cases where we have recording from the previous resident of the territory, in all ten cases the invading loon changed his yodel to increase the difference. We have no idea why this happens.

This research has been summarized in a film that is available at:

Recent Publications

Mager, John N., Walcott, Charles and Walter H. Piper. 2012 Male common loons signal greater aggressive motivation by lengthening territorial yodels. Wilson Journal of Ornithology 124 (1) 74-81.

Piper, W. H., Walcott, C and Mager, J. (2011). Marking Loons, Making Progress. American Scientist 99:220-227.

Mager, J.N., Walcott, C. and W. H. Piper (2010). Common Loons can differentiate yodels of neighboring and non-neighboring conspecifics. J. Field Ornithol. 81 (4):392-401.

Piper, W.H., Walcott, C., Mager, J.H. Spilker, F.J. (2008). Fatal battles in common loons: a preliminary analysis. Animal Behavior 75: 1109-1115.

Mager, J.H., Walcott, C. Piper, W.H. (2007). Nest platforms increase aggressive behavior in common loons. Naturwisseschaften. 95: 141-147.

Piper, W.H, Walcott, C., Mager, J.H., Spilker, FJ.(2007). Nestsite selection by male loons leads to sex-biased site familiarity. J. Animal Ecology 77: 205-210.

Mager, J. N., III, Walcott, C., Piper, W. (2007). Male common loons, Gavia immer, communicate body mass and condition through dominant frequencies of territorial yodels.  Animal Behaviour 73:683-690.

Mager, J. N., Walcott, C., and Evers, D.  (2007).  Macrogeographic variation in body size and territorial vocalizations of male Common Loons (Gavia immer).  Waterbirds 30 (1): 64-72.

Walcott, C. Mager, J and W. Piper (2006). Changing Territories, Changing Tunes: male loons, Gavia immer,   change their vocalizations when they change territories.  Animal Behaviour 71: 673-683.

Piper, W. H., Walcott, C., Mager, J. H., Perala M., Tischler K. B., Harrington E., Turcotte A. J., Schwabenlander M. and N. Banfield (2006).  Prospecting in a solitary breeder: chick production elicits territorial intrusions in common loons.  Behavioral Ecology 17: 881-888.

Walcott, C. (2005).  Multi-modal orientation in homing pigeons. Integr. Comp. Biol., 45:574-581.

Walcott, C. and David Evers (2000). Loon Vocal Tagging: An Evaluation of its Feasibility Using a Banded Population of Loons. In McIntyre, J.W. and D.C. Evers (eds.). 2000 Loons: Old history and new findings. Proceedings of a Symposium from the 1997 meeting, American Ornithologists' Union. North American Loon Fund, Holderness, N.H.

Walcott, C. (2000). Loony Tunes, Seney National Wildlife Refuge Newsletter.

Walcott, C., Evers, D, Froehler, M. and A. Krakauer (1999). Individuality in "Yodel" calls recorded from a banded population of Common Loons, Gavia immer. Bioacoustics 10: 101-114.

Walcott, C. (1996). Pigeon homing: Observations, experiments and confusions. J. exp. Biol. 199:21-27.

Walcott, C. (1992). Pigeons at magnetic anomalies: the effects of loft location. J. exp. Biol. 170:127-141.

Walcott, C. (1989). The disorientation of pigeons at Jersey Hill. In Proceedings of The Royal Institute of Navigation, RIN 89, Cardiff (with A.I. Brown).

Walcott, C. (1989). Show me the way you go home. Nat. Hist. Mag., pp. 40-46, Nov.

Courses Taught

Introductory Biology for Majors (BioG 101-104); Introduction to Behavior (BioNB 221); Bird Song