W255 Seeley G. Mudd Hall
Common House Spiders have sensitive vibration receptors on their legs. Because these spiders inhabit irregular “cobwebs”, vibrations from entangled prey are often not transmitted by web strands but rather travel to the spider as air-borne sound. This was a discovery that I made as a graduate student and I spent the next few years characterizing the receptor and how it worked.
The next 30 years were spent investigating how homing pigeons released in unfamiliar territory find their way home. One approach was to put tiny radio transmitters on the pigeon and follow it on its homeward journey with radio direction finding equipment from an airplane. Nowadays, GPS devices are small enough for a pigeon to carry giving even more accurate path information less expensively! Our research showed that pigeons used the sun as a compass reference but that if the sun was not visible, pigeons switched to a compass based on the earth’s magnetic field. But a compass is of little use unless you know the direction toward home. How pigeons do that is still controversial. We found that pigeons from one loft were disoriented at magnetic anomalies; places where the earth’s magnetic field was disturbed. Yet their siblings from a loft only a mile away, were well oriented at the anomaly. This suggests that under some circumstances the earth’s magnetic field may play some role in pigeon direction finding, but they also have alternative cues.
In recent years I have been studying the acoustic communication of Loons. Male loons have a characteristic territorial “yodel” which is different for each male. Yet when a male loon changes territory, it may change its yodel. This change is associated with the yodel of the male loon that was the previous resident of the territory as well as that of neighboring loons. If the intruding male’s yodel is different from that of the previous male and the neighbors, it doesn’t change. But if it is similar, it changes a lot. Exactly why this is important to the Loon is still mysterious.
Now, in retirement, I’ve returned to the spiders trying to understand more about their use of acoustic and vibration signals. I am also spending time making short videos of faculty and graduate research to post on CornellCast.
The Loon research has been summarized in a film that is available at: http://www.cornell.edu/video/?videoID=1166.
Mager, John N, III and Charles Walcott 2014 Dynamics of Aggressive Vocalizations in the Common Loon (Gavia immer): A Review. Waterbirds 37: 37-46.
Piper, Walter H, Mager, John N.,Walcott, Charles, Furey, Lyla, Banfield, Nathan, Reinke, Andrew, Spilker, Frank, and Joel A. Flory. 2015 Territory settlement in common loons: no footholds but age and assessment are important. Animal Behaviour 104: 155-163.
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.
Introductory Biology for Majors (BioG 101-104); Introduction to Behavior (BioNB 221); Bird Song