The year before this, on May 5, friends from Sterling College and I had found two just-hatched woodcock chicks near this display ground. The downy chicks were revealed after we almost stepped on the mother, who was as camouflaged as her babies. They had been under her, and after she flushed they flattened themselves into the loose leaves. I sketched them, to preserve what they looked like while they were trying to look like nothing at all—or like everything on a leaf-littered forest floor.
This year (2012), on April 25, I went to the same area to look for a possible nest. The nests, which female woodcocks make for their three or four camouflaged eggs, look like mere depressions or scrapes on the ground.
As soon as I got there I flushed a woodcock. To my great surprise, a second one remained at almost the same spot from which the other had left. She (the sex was my assumption; males and females look identical) walked slowly away from me, taking a few steps, stopping, and then gently rocking her body forward and back. As I advanced a few steps to take a photograph, she repeated the curious rocking motions and walked farther ahead of me. She made no attempt to hide, and I wondered why she rocked, making herself conspicuous. Perhaps to lead me away from her nest or babies? Maybe, but I recalled surprising a woodcock with young on a road some years earlier. She had made a squealing noise and then, like many ground-nesting birds, having caught my attention, had feigned a broken wing to entice me to follow her.
This woodcock’s rocking walk was different, but I had no doubt that it too was meant to get my attention. I continued following as she walked and rocked ahead of me. Finally she flew up, but went only about ten meters before landing back on the ground among the stems of a dense winterberry bush. What would she do now? Maybe go back to a nest? I withdrew thirty meters or so to wait and watch. As soon as I withdrew several meters she stopped walking and after a few moments also stopped rocking. Fifteen minutes later she still hadn’t budged. I walked back to the bush, and she moved to the opposite side of it, then walked on as before while I slowly followed. Soon, however, I turned and walked away, to make her think she had indeed outwitted me.
I happened to walk there again two weeks later, after having watched the nightly sky dances the evening before. This time, near noon, “the” woodcock was back at the same spot. Again she walked in front of me. But this time she stopped and flared her stubby tail feathers to show flashy white feathers that would normally be hidden from view. Now feeling even more convinced that she was trying to lead me away, I played along and kept following to see where we might end up. As before, she stopped whenever I stopped, then gently rocked her body. But this time instead of forward and back she rocked up and down, as if she were mounted on a light spring. Thinking that either eggs or babies were surely nearby, I searched for ten minutes, but found nothing.
If the woodcock was indeed a female, and if she had eggs or small young, she would return to the nest. So I climbed high into a maple tree that was behind other trees and far enough away that I would not be seen or at least not be seen as a threat. But I was close enough to be able to see with my binoculars. If she had young she would have to go back, or at least call to them to come out of their hiding places. I had a pleasant time in the tree. I saw a blue butterfly and also a fritillary butterfly below me fluttering along the ground. But the woodcock remained at the same place, in the wet depression at the edge of the field near the landing platform where the male had peented and launched into his sky dance.
I would again have let the question drop, assuming that the bird was a female leading me away from nest and eggs, and that I had been simply inept at finding them. But then a friend in Trenton, Maine, sent me a video he had taken of a woodcock doing the same thing, a month earlier, and in a driveway. This caught my attention, because it convincingly disproved my hypothesis: there was no way that his woodcock would have had a nest at that time, immediately after returning from migration. I now had an interesting problem. The woodcock, we recall, is one of the most-studied birds. So, not seeing the behavior again, I went to the Internet to look for an explanation of my woodcock’s puzzling behavior.
I found videos that showed woodcock doing precisely what I had seen—a behavior often described as the “swaying dance walk”—but that more or less poked fun at woodcocks as either simply stupid or uncannily endowed with almost magical powers. Biologists have long noted the behavior, and have proposed imaginative hypotheses to explain it. The first, suggested by O. S. Pettingill (1936), was “fear and suspicion.” Fear and suspicion may or may not be involved, but how would anyone prove it, and so what? “Reducing detection by minimizing shadows” was another hypothesis, offered by C. B. Worth (1976). But it is a stretch to think a woodcock acting as though suspended from a yo-yo reduces shadows, especially when ducking down and hugging the ground so clearly does. An alternative hypothesis, the most recent I found, was proposed in 1982: W. M. Marshall posited that the swaying dance walk was the way woodcocks forage for angleworms. This one paints a picture of woodcocks as truly ingenious. It goes this way: when earthworms detect vibrations such as those created by a bobbing woodcock, they squirm, and the woodcock detects the movement with its feet and probes for the squirming worm. Not everyone agrees that worms would make their presence known to woodcocks by squirming. Some claim instead that worms squirm their way out of the ground to the surface as a defense against tunneling moles that hunt them. So woodcocks’ rocking is really a mechanism to mimic the presence of moles so as to induce the worms to surface. Then, presto, the woodcocks get their meals. The problem is that, to my knowledge, none of these steps, never mind this sequence of them, has ever been observed, nor has anyone ever seen a woodcock actually capture a worm by this method. I don’t buy the hypothesis, simply by going by facts. All the rocking I saw was gentle and unlikely to have caused vibrations of the earth. Nor would a woodcock go worm hunting in the presence of a potential threat: instead, its impulse would be to fly away. And during worm hunting a woodcock would not stop hunting the moment a pursuer stopped, and proceed the moment it pursued again.
After replaying in my head what I’d seen of the swaying dance walk and re-watching my friend’s video of it recorded in early April when the ground was still frozen, I realized that this rocking-swaying walk was indeed intriguing, and that although proving what it did might be difficult, there was plenty of proof of what it could not do. For example, performing it on ice or on gravel driveways (as in several videos) could not yield earthworms. Also, when I sampled the icy ground where I had seen this display, the few worms I dug up were still unreactive and unable to crawl. Thus the swaying dance walk makes no sense as a foraging technique, but more sense as a distraction display, like the flashing of the white tail flag by a deer, the rattle of a rattlesnake, or the whistle of the wings of a dove when startled by potential predators.
The woodcock ground display, I now felt sure, alerts predators that they have been seen. Once a predator spots the bird, the peculiar placement of the woodcock’s eyes gives it the impression that the bird is watching it all the time. (Predators are acutely aware of eyes in assessing their chances of capturing prey.) Meanwhile, the rocking walk reinforces the signal that the predator has lost the advantage of surprise, and that continuing to hunt this prey would be a waste of time. If the display succeeds, the woodcock does not need to fly away, whether from a patch of cover, its favorite launch site for aerial displays, or perhaps just a good spot for finding worms.
The woodcock does its fabulous sky dance for one audience and its rocking walk dance for another, but both in order to be heard or seen. And so I too, prompted by a hypothesis, have been an audience to my woodcock. I was back at the cabin full time the next spring, but saw the woodcock only briefly. There were several abbreviated sky dances; then there was silence, except for the frogs. Just at the time for the sky dances, the vernal pool I had dug at the edge of the clearing was beginning its annual mating choruses of wood frogs and spring peepers. About five years earlier I had heard the first wood
frog there, but each year there were more: in 2014 more than two hundred females each laid a clutch of about two hundred eggs. The sound of nearly as many males was deafening, especially when combined with the even greater din of spring peepers. A woodcock male encountering such noise pollution would be unlikely to attract an audience, and might leave. For the hypothesis that birds respond to ambient noise there is precedent: birds living in noisy cities sing louder than those in the quiet countryside, suggesting that they calibrate their display with respect to their audience.
I have been an audience to a woodcock every spring since I heard my first one as a boy at my family’s farm. I especially recall the woodcock that came to a patch of snowmelt near an alder thicket in our back field. I saw it perform one night, and to hear it again, and again and again, required my getting a grandstand seat, which was a tent pitched as close as the bird allowed to the small scrub pine where it landed after each performance. I watched and learned, with no theory to prove. And now, sixty years later, I’m still learning by being an audience to a woodcock, and so can anyone learn by watching a starling, a sapsucker, a flicker, or a house sparrow—one wild bird at a time.
Acknowledgments
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BIRD WATCHING AND WRITING ARE BEST DONE SOLITARILY. However, making a book about the two may involve, among other things, suggestions and corrections, nudgings and judgings, and companionship of friends and kindred souls who critique and act as real or imagined sounding boards. In this case, they included (in no particular order) Alan Burger, Andrea Lawrence, Paul Spitzer, Lillian Reade, John Alcock, Margaret McVey, Greg Fell, Dean Leslie, Charles Sewall, Glenn Booma, Albert Reingewirtz, Andrea Lawrence, John Marzluff, Peter Miller, Duane and Nancy Leavitt, Lance Lichtensteiger, Alexandra and Garrett Conover, Joel Babb, and Lynn Jennings. Of these I acknowledge especially John Alcock for reading a draft of the manuscript and making valuable technical suggestions. I also thank my agent, Sandra Dijkstra, and Lynn Jennings, who have often nudged me in the right direction and helped me keep on course. I give sincere thanks to the editors and production staff of the publisher, Houghton Mifflin Harcourt, in this case specifically Camille Smith and Deanne Urmy, whose critical watchful eyes were in many cases more perceptive than mine. Last but not least, I have profited greatly from the generous support of Craig Neff and Pamelia Markwood, of the Naturalist’s Notebook of Seal Harbor, Maine, for digitizing, archiving, and storing almost all of my illustrations and making the appropriate ones conveniently available to be used for this publication.
Further Reading
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FLICKERS IN THE HOUSE
Bent, Arthur C. 1939. Life Histories of North American Woodpeckers. Washington, DC: Government Printing Office. 342 pp.
Kilham, L. 1959. Early reproductive behavior of flickers. Wilson Bulletin 71:323–336.
———. 1983. Life History Studies of Woodpeckers of Eastern North America. Cambridge, MA: Nuttall Ornithological Club. 240 pp.
Sherman, A. R. 1910. At the Sign of the Northern Flicker. Wilson Bulletin 22:135–171.
A QUINTET OF CROWS
Caffree, C. 1992. Female-biased delayed dispersal and helping in American crows. The Auk 109(3):609–619.
Heinrich, B. 1999. Mind of the Raven: Investigations and Adventures with Wolf-Birds. New York: Harper-Collins. 380 pp.
Kilham, L. 1984. Cooperative breeding of American crows. Journal of Field Ornithology 55(3):349–356.
———. 1985. Behavior of American crows in the early part of the breeding cycle. Florida Field Naturalist 13(2):25–48.
Marzluff, J. M., and T. Angell. 2005. In the Company of Crows and Ravens. New Haven, CT: Yale University Press. 384 pp.
Marzluff, J. M., J. Walls, H. N. Cornell, J. Withey, and D. P. Craig. 2010. Lasting recognition of threatening people by wild American crows. Animal Behaviour 79:699–707.
Verbeek, N. A., and C. Caffrey. 2002. American Crow (Corvus brachyrhynchos). The Birds of North America Online, ed. A. Poole. Ithaca: Cornell Laboratory of Ornithology. http://bna.birds.cornell.edu/BNA/
GETTING TO KNOW A STARLING
Baptista, L. F., and L. Petrinovich. 1984. Social interaction, sensitive periods, and song template hypothesis in the white-crowned sparrow. Animal Behaviour 36:1753–64.
Gentner, T. Q., K. M. Fenn, D. Margoliash, and H. C. Nusbaum. 2006. Recursive syntactic pattern learning by songbirds. Nature 440:1204–07.
Murmuration of Starlings. See http://www.youtube.com/embed/88UVJpQGi88.
West, M. J., A. N. Stroud, and A. P. King. 1983. Mimicry of the human voice by European starlings: The role of social interaction. Wilson Bulletin 95:635–640.
West, M. J., and A. P. King. 1990. Mozart’s Starling. American Scientist 78:106–114.
WOODPECKER WITH A DRUM
Bent, A. C. 1939. Life Histories of North American Woodpeckers. Bulletin of the U.S. National Museum 174:1–1322. Reprinted by Dover Publications, New York, 1964.
Daily, G. C., P. R. Ehrlich, and N. M. Haddad. 1993. Double keystone bird in a keystone species mix. Proceedings of the National Academy of Sciences USA 90:592–594.
Kilham, L. 1983. Life History Studies of Woodpeckers of Eastern North America. Nuttall Ornithological Club no. 20:1–240.
Walters, E. L., E. H. Miller, and P. E. Lowther. 2002. Yellow-bellied Sapsucker (Sphyrapicus varius). The Birds of North America, no. 662, ed. A. Poole and F. Gill. Philadelphia: The Birds of North America, Inc.
BARRED OWL TALKING
Angell, T. 2015. The House of Owls. New Haven, CT: Yale University Press. 203 pp.
Bent, A. C. 1938. Life Histories of North American Birds of Prey, part 2. U.S. National Museum Bulletin, no. 170.
Eckert, A. W. 1974. The Owls of North America. New York: Doubleday.
Freeman, P. L. 2000. Identification of individual barred owls using spectrogram analysis and auditory cues. Journal of Raptor Research 34:85–92.
Heinrich, B. 1987. One Man’s Owl. Princeton, NJ: Princeton University Press. 224 pp.
Klatt, P. H., and G. Richison. 1993. The duetting behavior of eastern screech owls. Wilson Bulletin 105(3):483–489.
Odum, K. L., and D. J. Merrill. 2010a. A quantitative description of the vocalizations and vocal activity of the barred owl. Condor 112:549–560.
———. 2010b. Vocal duets in nonpasserines: An examination of territorial defense and neighborhood-stranger discrimination in a neighborhood of barred owls. Behaviour 147:619–639.
———. 2012. Inconsistent geographic variation in the calls and duets of barred owls (Strix varia) across an area of genetic introgression. The Auk 129(3):387–398.
HAWK TABLECLOTHS
Berger, S., R. Disko, and H. Gwinner. 2003. Bacteria in starling nests. Journal of Ornithology 144:317–322.
Brouwer, L., and J. Komdeur. 2004. Green nesting material has a function in mate attraction in the European starling. Animal Behaviour 67:539–548.
Clark, L., and J. R. Mason. 1985. Use of nest material as insecticidal and anti-pathogenic agents by the European starling. Oecologia 67:169–176.
Gracelin, D. H. S., A. J. Britto, and P. B. J. R. Kumar. 2012. Antibacterial screening of a few medicinal ferns against antibiotic resistant phytopathogens. International Journal of Pharmaceutical Sciences and Research 3:868–873.
Gwinner, H., and S. Berger. 2005. European starlings: Nestling condition, parasites, and green nesting material during the breeding season. Journal of Ornithology 146:365–371.
Gwinner, H., M. Oltrogge, L. Trost, and U. Nienaber. 2000. Green plants in starling nests: Effects on nestlings. Animal Behaviour 59:301–309.
Heinrich, B. 2010. The Nesting Season: Cuckoos, Cuckolds, and the Invention of Monogamy. Cambridge, MA: Harvard University Press. 352 pp.
Heinrich, B. 2013. Why does a hawk build with green nesting material? Northeastern Naturalist 20(2):209–218.
Hoffman, D. 2003. Medical Herbalism: Principles and Practice. Rochester, VT: Healing Arts Press. 588 pp.
Lyo
ns, D. M., K. Titus, and J. A. Mosher. 1986. Sprig delivery by broad-winged hawks. Wilson Bulletin 98:469.
Matray, P. F. 1974. Broad-winged hawk nesting ecology. The Auk 91:307–324.
Orians, G. F., and F. Kuhlman. 1956. The red-tailed hawk and great horned owl populations in Wisconsin. Condor 58:371–385.
Rodgers, J. A., Jr., A. S. Wenner, and S. T. Schwikert. 1988. The use and function of green nest material by wood storks. Wilson Bulletin 100:411–423.
Rosenfield, R. N. 1982. Sprig collection by a broad-winged hawk. Raptor Research 16:63.
Srivastava, K. 2007. Importance of ferns in human medicine. Ethnobotanical Leaflets 11:231–234.
Welty, J. C. 1962. The Life of Birds. Philadelphia: W. B. Saunders. 720 pp.
Wimberger, P. H. 1984. The use of green plant material in bird nests to avoid ectoparasites. The Auk 101:615–618.
VIREO BIRTH CONTROL
Alcock, J. 2005. Animal Behavior: An Evolutionary Approach, 8th ed. See ch. 12, The evolution of parental favoritism, pp. 426–435.
One Wild Bird at a Time Page 17