Birders know that few thrills parallel the meeting of a new bird species. We anticipate their migrations, we listen to their calls on the Merlin Bird ID app, and we find ourselves venturing farther and farther from home to add them to our list. Descendants of prehistoric creatures become collectables — numbers. 

“But what these numbers leave out is nearly all of a bird’s life,” Joan Strassmann writes in the introduction to her book “Slow Birding.” “What are the birds doing? What can you learn about the birds?”

When focusing only on the novelty of birding, so much opportunity for grounding and connection is lost. As an evolutionary biologist and lover of animal behavior, Strassmann calls birders to tune our curiosity toward the life stories taking place in the canopies all around us. “What if instead we stayed close to home and watched the birds that intersect our lives?” she asks. 

“Slow Birding” — and its companion, “The Slow Birding Journal” — will lead birders everywhere to find a deeper appreciation for even the most familiar avian kin.

Joan E. Strassmann is an award-winning teacher of animal behavior, first at Rice University in Houston and then at Washington University in St. Louis, where she is Charles Rebstock professor of biology. She has written more than two hundred scientific articles on behavior, ecology, and evolution of social organisms. She is a member of the National Academy of Sciences and the American Academy of Arts and Sciences and a fellow of the Animal Behavior Society and the American Association for the Advancement of Science, and has held a Guggenheim Fellowship. She lives with her husband in St. Louis, Missouri.

Reprinted from Slow Birding by arrangement with TarcherPerigee, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © 2022, Joan E. Strassman

Cedar Waxwing: Evanescent Berry Pickers

Cedar Waxwings are like thoughts that arise unbidden in meditation. Try to focus on your breath, on the pattern of light, color, and dark right in front of you. And yet thoughts wisp in like bits of smoke, to-do lists, something left astray, or a worrying conversation. Let them all go and focus on your breath, my meditation guide tells me. Still, thoughts float in unbidden, just as Cedar Waxwings arrive unpredictably from on high, their sweet whistles in the morning sky too high-pitched for some to hear. I could not take you to see Cedar Waxwings, but I could tell you when they are suddenly here. These enigmatic birds present a mystery I would love to solve. 

I could not take you to see Cedar Waxwings, but I could tell you when they are suddenly here.

Cedar Waxwings are an improbable bird, from the black mask outlined in white to the feathery crest, or the tail dipped in yellow the color of yolk. Best of all are the little waxy tips of crimson on the ends of some wing feathers. Their other colors are more subtle, a yellow wash on the belly, chestnut on the head and neck fading to gray across the back and then intensifying to black on the tail. They look as if painted by one of the great Japanese artists of long ago, delicate yet strong, subtle yet stunning.

I see Cedar Waxwings sporadically in Flynn Park, two blocks from my home. In autumn, they twist around in the Sargent cherry trees as they eat small fruits, not competing for fruit with one another but sometimes chasing a robin away from a cherry-filled branch. Cedar Waxwings are always in groups, so when I see one, I know to look for others. But I never know exactly when I will encounter them. First, I hear their thin whistles. It is a pitch so high that my husband cannot hear it. 

Cedar Waxwings breed in the northern half of the United States and the southern half of mainland Canada, south of the boreal forest in open woods and old fields. They move out of the northernmost parts of their breeding range to winter along the southern fifty miles of Canada and then all the way south to Nicaragua. In St. Louis, we have Cedar Waxwings year-round according to eBird. I like to think of Cedar Waxwings wintering in Mexico, country of my early childhood. Perhaps they are in the eucalyptus groves of Chapultepec Park, where I once played. But even there they do not stay in one place long, as I will discuss later. 

Cedar Waxwings are true frugivores. From October through April they survive almost entirely on fruit.¹ Jean McPherson did a thorough study of their diet during the winters of 1983 to 1985 on the University of Oklahoma campus in Norman.² She rode her bike frequently through campus, documenting the amount of fruit on trees and the Cedar Waxwings that fed on them from early December to mid-May. She rode her 7.5-mile route eighty-three times, stopping whenever she heard or saw Cedar Waxwings.

I guess Cedar Waxwings were not so hard for her to find once they came to campus. But that could vary a lot from year to year. There were none in 1985 until late January, for example. But then on February 27, 1985, she saw a record 673 birds!

McPherson found that Cedar Waxwings favored the sticky white fruits of mistletoe, stripping these berries entirely before trying other fruits. Their second favorite fruit was hackberry, followed by yaupon and deciduous holly berries, but really any fruit would do.

This is a bird so social, it will die when alone rather than eat.

Next, McPherson looked at food preference in aviaries, where she could control what the birds were fed. She wanted to study individual birds and their personal choices, but when she put a Cedar Waxwing in a cage by itself, it sat there and refused to eat.³ This is a bird so social, it will die when alone rather than eat.

McPherson found that in groups of eight birds, they ate the fruit readily, allowing her to do her study and conclude that Cedar Waxwings like small, red fruit best and do not seem to take into account nutritional aspects like protein content. But that does not explain their love of white mistletoe fruits.

It takes a special physiology to live on a diet of so much fruit. Margaret Morse Nice temporarily adopted a fledgling Cedar Waxwing to see how it digested fruit.⁴ She fed it fruit first thing in the morning, then waited for the fruit to work its way through the bird’s digestive system. Since fruit has so little protein, she reasoned that the Cedar Waxwings would digest it quickly. And so they did. Margaret found that blueberries took twenty-eight minutes from entry to exit, chokecherries forty minutes, and black cherries twenty minutes. Her lone Cedar Waxwing fed readily, but it was not truly alone because it was in a room with two Song Sparrows that the youngster took to be his own kind, begging readily from them.

Because they are so dependent on ripe fruit, Cedar Waxwings reproduce later in summer than other birds. The first fruits they eat in the spring are often berries left over from the previous year.

Perhaps the best way to determine what a bird eats and when it eats it is to simply shoot it and see what is in its stomach. We do not do this anymore, but there was a time when it was normal to shoot birds for study. The US Bureau of Biological Survey, now the US Fish and Wildlife Service, shot thousands of birds and documented what was in their stomachs between 1885 and 1950. Mark Witmer went to those records and reported on the stomach contents of 283 Cedar Waxwings.⁵ From November to April, their stomachs were half full of red cedar berries. Other common fruits in their stomachs included apples, crab apples, black haw, American pokeweed, riverbank grapes, blackberries, mulberries, service berries, and black cherries. In all, Witmer found the diet of these birds was 84 percent fruit, even more than that of American Robins, at 57 percent fruit, the next highest.

If I followed the appearance of fruit on trees, I might more regularly find Cedar Waxwings. Maybe this is what Alan Monroy-Ojeda and his team had in mind when they banded birds including Cedar Waxwings in the lush Ethnobotanical Garden in Oaxaca, Mexico.⁶ Though it is only five acres, the garden’s grounds and water supply make it a natural refuge for migrants. Monroy-Ojeda trapped birds with mist nets on the last Sunday of each month between December 2001 and April 2010. His crew identified, banded, and measured them before letting them go. The most common migrants they caught were Cedar Waxwings, Warbling Vireos, Nashville Warblers, Yellow-rumped Warblers (the Audubon’s subspecies), Western Tanagers, and Orchard Orioles. In all, they caught 1,565 birds. If the birds did not already have a band, they banded them with an aluminum band embossed with a traceable number. A fifth of them had already been caught before, either the same winter or a previous winter.

But they never recaptured a Cedar Waxwing.

But they never recaptured a Cedar Waxwing. Even on these wintering grounds, Cedar Waxwings are evanescent and social, tracking the fruit trees and neither staying long enough to be recaptured in one place nor necessarily returning the next year.

I don’t know if the migrants I see in the spring come all the way from Oaxaca. They are here in number by May. To be exact, last spring I heard them at home for the first time on May 11, when three flew overhead then perched on a dead snag high in a maple tree across the street. That spring I last saw them on June 1, when twenty individuals flew overhead, pausing in two separate groups in the high tops of sweetgums and oaks. I saw them nearly every day between May 11 and June 1, 2020, for a total of 199 birds, all likely to have been different individuals given how they move around. They were probably heading north, perhaps to my home state of Michigan. I have not figured out where to find Cedar Waxwings breeding near my home, though my Missouri Breeding Bird Atlas says they are here.⁷ I did not see them again until October 3, as they moved through flying southward.

…

Cedar Waxwings flit in and out of my life since I never know when I will see them. There is no lifetime researcher of Cedar Waxwings the way there is for House Wrens, Dark-eyed Juncos, Northern Flickers, or Cooper’s Hawks. Maybe it is too discouraging to study a bird that you band and come to love only to never see it another season. But many of us love them anyway.

…

CEDAR WAXWING ACTIVITIES
FOR SLOW BIRDERS

1. Check the size of the flocks. If there is one Cedar Waxwing, there will be more. See if you can count the flock size. It might be easiest as they fly away from a fruit tree, for when one leaves, they all tend to leave. What do flock sizes relate to? Are flocks in trees with copious fruits larger? Are they larger at the beginning or end of the season?

2. Watch Cedar Waxwings in a fruit tree. If you have fruiting trees nearby, Cedar Waxwings are likely to find them. Pick out one bird and watch it eat. Can you count the berries it swallows per minute? With their short guts and fast digestion, they defecate often. See if you can observe that too. What are their techniques for getting berries? Do they shake the branches to get them to fall? Maybe their techniques vary when there are a lot of birds nearby. Do the Cedar Waxwings eat all the fruit or leave before it is gone? Can you quantify this? What would you count?

3. Watch a nest. If you are lucky enough to find a nest, perhaps near a stream, take some time to watch it. See who comes and who goes and for how long. Maybe you will be there when the babies leave the nest and can watch their early attempts at flight. You won’t be able to capture one and watch it the way Margaret Morse Nice did, but wild watching is just as rewarding. See if you can watch the young birds land, as they have trouble with that long after they succeed in flying.

1. M.C. Witmer, D.J. Mountjoy, and L. Elliot, “Cedar Waxwing (Bombycilla cedrorum),” version 1.0, in Birds of the World, ed. A.F. Poole (Ithaca, NY: Cornell Lab of Ornithology, 2020). 
2. J.M. McPherson, “A Field Study of Winter Fruit Preferences of Cedar Waxwings,” The Condor 89, no. 2 (1987): 293–306. 
3. J.M. McPherson, “Preferences of Cedar Waxwings in the Laboratory for Fruit Species, Colour and Size: A Comparison with Field Observations,” Animal Behaviour 36, no. 4 (1988): 961–69. 
4. M.M. Nice, “Observations on the Behavior of a Young Cedar Waxwing,” The Condor 43, no. 1 (1941): 58–64. 
5. M.C. Witmer, “Annual Diet of Cedar Waxwings Based on US Biological Survey Records (1885–1950) Compared to Diet of American Robins: Contrasts in Dietary Patterns and Natural History,” The Auk 113, no. 2 (1996): 414–30. 
6. A. Monroy-Ojeda et al., “Winter Site Fidelity and Winter Residency of Six Migratory Neotropical Species in Mexico,” Wilson Journal of Ornithology 125, no. 1 (2013): 192–96. 
7. B. Jacobs and J.D. Wilson, Missouri Breeding Bird Atlas (Jefferson City: Missouri Department of Conservation, 1997). 

Reprinted from Slow Birding by arrangement with TarcherPerigee, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © 2022, Joan E. Strassman