Birds Above All Else

There is an exchange between two characters in Tom Stoppard’s mind-bending play Arcadia (1993) that captures in a clever way the essence of science. In Act Two, Scene VII, two characters in the present day on the Coverly estate are discussing events that may or may not have occurred there in 1809. Hannah Jarvis, an author, is skeptical of the conclusions being advanced by another character, an academic, regarding what happened over a century ago. Valentine Coverly, a graduate student in mathematics, is the scion of the Coverly family that owned, and still owns, the estate.

Valentine It may all prove to be true.

Hannah It can’t prove to be true, it can only not prove to be false yet.

Valentine (pleased) Just like science.

Hannah’s statement, with its double negatives, does address a core tension in science: no conclusion, no matter how thoroughly tested, is above challenge. As Carl Sagan wrote, in The Demon-Haunted World: Science as a Candle in the Dark (1996), “Except in pure mathematics nothing is known for certain (although much is certainly false).”

But there are some propositions in science that have moved beyond Hannah’s cautionary statement into the realm of nearly universally accepted scientific facts. Evolution through natural selection is one of them. The subject of paleontologist Steve Brusatte’s masterful new book, The Story of Birds: A New History from Their Dinosaur Origins to the Present (2026) should be another, if it isn't already. Brusatte writes:

Birds are dinosaurs.

This realization is one of the greatest achievements in the history of paleontology.

(I read an e-book version of this book so I won’t be providing page numbers for quotations.)

The book reaches two conclusions: birds are dinosaurs, and birds are marvelous creatures. It is a heady and graceful work, serving not just the fossil lover, but the bird lover as well. It's also rich fare for someone in search of how science has been done in the past and is done now. Basically, it's a good read.

That he is completely smitten by birds, ancient and present, is, if possible, an understatement. To offer just one example of the language he uses when extolling birds, early on he writes that birds are

some of the most unusual, the best adapted, the most fine-tuned animals that live today, and that have ever lived, in the 4.5-billion-year history of the Earth.

Though Brusatte describes his personal connections to this work, he is restrained and does not fall victim to the temptation, succumbed to in much popular science writing, of becoming the hero of the story.

Undoubtedly and deservedly so, Archaeopteryx is the hero of the paleontology side of the story that Brusatte tells. The fossils of this species, first discovered in Germany in the early 1860s, show that the animal sported feathers. It is considered the oldest bird, dating from the late Jurassic (about 150 million years ago). The picture below shows the so-called “Berlin” fossil of the species. (This image is in the public domain one of the several fossils of the species. It is published under the Creative Commons Attribution-Share Alike 3.0 Unported license.)

There are human heroes in this story, as well. Though Brusatte profiles many of the scientists who have done significant, groundbreaking work exploring the evolution, development, and family ties of birds, I am most taken by two who were involved in either first enunciating that birds are dinosaurs, or reviving that position after years of willful neglect: biologist and Darwin champion Thomas Henry Huxley (1825-1895) and paleontologist John Ostrom (1928-2005).

Huxley is a fascinating personality, faithful to his working class origins and dogged in his commitment to what he perceived as true. Brusatte highlights the bold steps Huxley took in lectures in the 1860s to lay out why he believed: "Aves (birds) has its root in the dinosaurian reptiles." The key elements to his argument were the combination of bird and dinosaur attributes that he detected in two recent fossils discoveries; these approached the issue from different directions. First, there was the earliest bird, Archaeopteryx, which featured some characteristics of reptiles, and, then, there was Compsognathus, a reptile also from the late Jurassic that sported some avian features. Huxley was brilliant in building his argument to a striking and irresistible conclusion.

Brusatte describes how, in time, this conclusion about the relationship of birds to dinosaurs fell out of favor and faded into the background. Some hundred years after Huxley had staked this claim, paleontologist John Ostrom revived it in a profound way. Ostrom had found and named Deinonychus, a coelurosaur theropod dinosaur that lived during the early to late Cretaceous (115 to 98 million years ago). Ostrom argued that the coelurosaurs, unlike their lumbering, huge brethren (think T. rex), were small, agile, and quick predators. They were also light weight, given that their bones were hollow. (Coelo, the Greek root, for their genus name means “hollow,” and, by the way, birds have hollow bones.)

Ostrom knew the coelurosaurs from his find and others which dated back to the Jurassic.  After closely analyzing the four Archaeopteryx fossils known at the time, he came to a profound conclusion. In a brief, one-page article, The Ancestry of Birds, which appeared in the March 9, 1973, issue of Nature, Ostrom listed the 21 specific morphological attributes of Archaeopteryx that he posited were shared by coelurosaurs. He introduced the list by writing:

The following coelurosaurian features of Archaeopteryx collectively are here considered as prima facie evidence of a coelurosaurian (Theropoda) ancestry of birds.

He concluded that Archaeopteryx had gained these features through "direct inheritance from a small coelurosaurian ancestor."

Of Ostrom's article, Brusatte writes:

It is probably the single most important page ever written about dinosaurs.

He summarizes what Ostrom was demonstrating as follows:

Birds are a type of coelurosaur, which is a type of theropod, which is one of many types of dinosaurs.

In support of the book’s central conclusion, Brusatte delineates in detail how the pedigree of many typical bird traits and features is actually dinosaurian in nature. These traits range from hollow bones, to feathers, to nesting, to the laying of colorful, hard-shelled eggs, to an efficient respiratory system, and to relatively small size (true of many dinosaurs), as well.

Of course, what possibly most marks an animal as a bird is its ability to fly. Archaeopteryx, the most primitive bird, was a flyer, but only a crude one. Brusatte outlines how flight probably arose and, most importantly, uses this as one of several powerful examples in the book to illustrate a central aspect of evolution. A feature that arises for one purpose may, over time, come to serve another, different one. Flight is a clear example of this. Feathers, so critical to birds' flight, arose among dinosaurs, not for flight, but possibly initially as "sensory devices," and then for insulation. Indeed, Brusatte calls feathers a "default condition" for dinosaurs (think, hair for mammals). In this case, over time, evolution repurposed the early feathers into an essential, powerful component of a constellation of features, including the forearms evolving into wings, that would be necessary for birds to take flight. Light weight from hollow bones clearly contributed.

If one were foolish enough to skip the paleontological heart of this book with its treatment of how and why birds evolved and, instead, just read the last chapter, it would still be worth the price of admission. That chapter, titled Marvelous Modern Birds: Intelligence, Cognition, Birdsong, and How Birds Are Still Evolving Today, is a précis of much that makes extant birds so universally fascinating. In this chapter, Brusatte makes good on his assertion that "birds are among the smartest, cleverest, and most cognitively advanced animals on the planet." Some of today's birds, he shows, think about the future, engage in abstract thought, fashion tools, among other impressive mental and physical feats. I was particularly taken with the oscines, the songbirds, whose songs are not innate or instinctive, but are, instead, learned by immature birds from their elders. They are "vocal learners," no mean feat, considering the complexity of many of their songs.

Finally, birds have faced dramatic threats to their survival from their origins, threats that have included such events as the mass destruction at the end of the Cretaceous, and never-ending challenges from climate change. Sadly, in recent centuries, the impact of Homo sapiens on these dinosaurs has been profound, with many species lost to hunting and wanton destruction of the environment, and billions of individuals killed by the domestic cats we seem to be unable to keep indoors (but, despite claims to the contrary, only a piddling number are lost to wind turbines). Brusatte demonstrates how birds have endured these challenges, showing that they are truly survivors. He writes:

The future is uncertain. And paleontologists like me are always more comfortable looking to the past than predicting what might lie ahead. But as the world changes rapidly around us — because of us — I am willing to make a bet. The Age of Birds will persist, even if the Age of Humans does not.

Climate Change Hits Home: A Review of The Lost Trees of Willow Avenue

Mike Tidwell, climate activist and founder of the Chesapeake Climate Action Network, posits that, if you were to throw a dart at a spinning globe, no matter where the dart punctured the surface of the globe, that actual spot on the Earth would have an ominous tale to tell of the effects of climate change.

Tidwell has chosen a single year, 2023, and the small block on which he lives in Takoma Park, Maryland, in the Washington, D.C., suburbs, from which to sound the alarm over the damage being done by our sharply warming planet.  His book, The Lost Trees of Willow Avenue:  A Story of Climate and Hope on One American Street (2025), tells how climate change has come to his own block.  It’s an eminently readable volume, but, to be blunt, it scared the shit out of me.

This account came into being when Tidwell realized the giant oaks on his block and in his town were in crisis.  These trees, which had survived for decades or, sometimes, for a century or more, were dying in staggering numbers.  The loss of giant oaks in a single suburban block cannot be missed, because they leave such a massive empty space at eye level and in the overhead canopy.  That is not the only impact.  He writes, “Oaks are the miracle trees of both urban and rural forests.”  (p. 128) They are crucial to the entire local ecosystem, hosting and supporting a wide range of insect and bird life.  And it wasn’t just the oaks in peril.  During the period from 2019 to 2022, Takoma Park, a town of just 2.1 square miles with about 18,000 residents, lost 1,200 trees, the largest portion of them oaks.  A study from 2022 reported the loss of a startling 45 acres of the town’s tree canopy.

The causes for this still ongoing season of death are myriad, but ultimately mostly tied to the increasingly weird and changing weather patterns that have taken hold as the worldwide climate warms.  Rising temperatures change weather patterns, fostering prolonged droughts and storms whose flooding downpours are fed by the ever greater amounts of moisture held in the warming atmosphere.  Seasons are marked by atypical temperatures throwing trees’ internal cycles out of sync with damaging consequences.  The deluges of rainfall saturate the ground fostering the spread of insects and fungus, which attack the already stressed trees.  Takoma Park experienced all of this.  A recipe for a local, national, and global ecological disaster.

The stakes associated with the death of trees are high.  By sequestering a significant portion of the carbon dioxide we’ve poured into the atmosphere since the dawn of the industrial age, trees have helped mitigate some of the worst effects on the climate of that greenhouse gas.  Though the loss of trees reduces their important contribution to the planet’s health, what particularly worries Ning Zeng, one of Tidwell’s neighbors, is the prospect that the carbon dioxide contained in those myriad felled trees will be released back into the atmosphere.  Zeng, a professor of climate science at the University of Maryland, wants to bury as many of them under conditions that will preserve them for centuries.  Tidwell recounts in some detail the time-consuming challenges Zeng faces as he works to arrange for the burial of 5,000 tons of dead trees.

I would characterize it as a noble response to the crisis, but a drop in the bucket.  For instance, at the time Zeng worked to remove 5,000 tons from a site in Baltimore, there were many thousands of tons of dead trees still there poised to release their carbon dioxide.

Tidwell documents the broad scope of climate change-induced blows that his block and his town has endured, a tale told well with vignettes of neighbors, experts, and local politicians who are engaged in trying to respond to the damage being done.  The efforts range from trying to divert rainfall from low lying areas, from streets and basements, to planting trees that have evolved to thrive in a wet environment, to installing solar panels on roofs now exposed to the sun due to the loss of canopy cover, to promoting electric vehicles, and so on.

It’s quite clear to him that more, much more is needed on an unprecedented scale and that it must have a potential impact that dwarfs what’s been done so far.  Clean energy isn’t enough to reverse the damage.  Geoengineering on a vast scale may well be needed.  He describes many of the proposed methods being explored to draw carbon dioxide from the atmosphere.  But he is clearly attracted to seriously researching a different approach:  solar radiation modification, that is, seeding the atmosphere with aerosols (particulate emissions) to reflect sunlight away from the planet.  It’s a bold approach that may hold great potential to addressing the immediate crisis, but also may bring serious, negative outcomes.  At this stage, we just don’t know.

He is influenced by The Open Letter Regarding Research on Reflecting Sunlight to Reduce the Risks of Climate Change, issued in early 2023 and signed by more than 110 of the world’s leading climate scientists.  The letter posits that reducing greenhouse gases at this stage is too late to address the planet’s current and future warming.  Instead, it is urgent that we explore quickly whether and how to put aerosols into the atmosphere.

It’s a sobering thought that solar radiation modification is the “hope” in the book’s title.

Why Do Wrens Build Dummy Nests? It's Complicated

I find much to like about house wrens, including their scientific name: Troglodytes aedon.  It’s very appropriate for this vigorous singer and cavity nester. Troglodyte is from the Greek for “hole or cave dweller,” while aedon, also Greek in origin means “nightingale.”  But, to be honest, it’s a challenge to love this contradictory animal.

Naturalist John James Audubon, clearly captivated by it, described the house wren as a “sweet little bird” that was “sprightly, active, vigilant, and courageous.”  In contrast, essayist Margaret Renkl pronounced it “a tiny, feathered terrorist,” wreaking havoc on the nests, eggs, and nestlings of other song birds in her Tennessee yard.  In fact, it’s both:  perky in general and vicious in its relationships with other birds.  (See the reference section at the end for links to cited sources.)

The illustration of the house wren that Audubon included in The Birds of America is quite revealing:

He showed the birds nesting in a hat.  There’s no cavity too outlandish for the house wren when it comes time to build nests and, furthermore, the nest-building impulse leads the little bird to construct multiple nests during the breeding season, many of which go unused.  The purpose of these non-breeding nests, often called “dummy nests,” has eluded researchers for a long time and, as I explore below, we’ve yet to fashion an accepted explanation for the behavior.

The issue of dummy nests is quite real for me.  I have been monitoring a group of seven bird boxes built according to specifications appropriate for bluebirds, but used by a variety of song birds.  My particular array of boxes lies in a wooded section of my community which means that bluebirds are unlikely to be residents:  this immediate setting just isn’t their kind of territory.  Instead, so far this season, the boxes have been occupied variously by Carolina chickadees, tufted titmice, and house wrens.  The first two species have used boxes at one end of the wooded stretch I patrol while the last, the wrens, have been active mostly at the other end of this trail.

The pictures below show house wren eggs recently laid in one of the boxes and a parent perched on top of that box.

House wrens build a distinctive nest of a wide variety of materials, typically starting with a base of twigs.  In addition to the one box where eggs have been laid and brooding is underway, I have found two other boxes with solely the telltale first layer of twigs of a wren nest:  dummy nests, I’ve concluded.  One is shown below - this is a view with the side of the bird box swung open.  This nest has never been used.

And therein lies a key question:  why?  Why would male house wrens (it is apparently the males that do this) expend the energy to build nests that won’t be used for propagating the species?

My first introduction to the explanations advanced for this behavior was in the rather dated but still useful A Field Guide to the Birds’ Nests (1975).  Of wren nest building in its breeding territory, it states:  “Male arrives first, establishes territory, builds dummy nests of twigs in all or most of available nest sites.  Female may or may not accept prechosen site; may or may not accept male’s incomplete twig nest.”

As I read some of the literature on the subject, I was quite pleased to come across a recent review of the research by Elise Isabella Macqueen and Graeme Douglas Ruxton.  The authors consider all of the peer-reviewed literature on this avian behavior (for all species, not just wrens) and posit that it proffers four “non-exclusive mechanisms” to explain this phenomenon.  They review the evidence for these explanations and discuss the logical “plausibility” of each. 

First, though, it’s useful to briefly discuss three explanations that, according to Macqueen and Ruxton, prior authors had suggested for this behavior:  (1) the birds were practicing their nest-building skills, (2) they were expending “excess sexual energy prior to pairing,” or (3) they were establishing territory (the one promoted by the field guide quoted above).

They summarily dispose of all three of these explanations, characterizing them as “now widely accepted to be implausible.”  Of the first (getting in practice), the authors note that the dummy nests usually are poorly fashioned compared to the nests actually used and that the activity is not confined to young males.  With regard to letting off steam, they said that males in many species continue the activity even after breeding.  Finally, when it comes to marking territory, Macqueen and Ruxton assert that this would be a singularly inefficient way to do that compared to singing and displays.

According to the authors, the four explanations that are currently advanced to explain this nest building activity posit that the dummy nests:

(1) mislead predators or parasite species ("predation avoidance hypothesis")

(2) sexually signal that the builder is a high quality male ("sexual selection - signalling [sic] hypothesis")

(3) offer shelter ("fledgling shelter hypothesis"), and/or

(4) defend against other species taking over an occupied nest ("nest usurpation defence [sic] hypothesis").

The authors are often quite critical of the evidence advanced in support of any of these hypotheses, outlining how the methods used to test them might have been improved.  The paucity of conclusive evidence for any one, despite a fairly substantial amount of research effort devoted to this cause, is striking, though perhaps to be expected given the observational and experimental challenges of working in the field with birds.  Macqueen and Ruxton deconstruct the underlying logic of each of the current hypotheses, devoting more attention to the first two, while skating quickly over the last two.

Here then are brief summaries of their analysis of each hypothesis, with a focus on what they say about the inherent logic behind them.

Predation Avoidance  The underlying assumption for this hypothesis is that predators (other birds or other animals) will give up a search in a particular area for an occupied nest if they encounter several empty nests.  Macqueen and Ruxton suggest this hypothesis could be tested experimentally but find little evidence in the research of such testing.

That said, the authors write, "We are doubtful of its logical plausibility."  It is, they assert, "an unlikely functional explanation for building multiple nests."  They question the central assumption that a predator would abandon a search which, past experience might suggest to it, could yield a rich reward.  Though for some ground dwelling predators the costs of continuing a heretofore fruitless search might be relatively high, for birds looking for prey they might not be.  More telling, the authors assert that the search conducted by predators wouldn't be random among all local nests, but would be guided by key signals like smell and noises.

Sexual Selection/Signaling  According to Macqueen and Ruxton, at its heart, this hypothesis assumes that the building of multiple nests signals to potential mates that here is an individual with superior genes who has the physiological resources to build several nests, or that only an individual with a highly desirable territory, offering much available nesting material, could do this.

The difficulties for testing this hypothesis are substantial.  Close scrutiny of the behavior of individual birds is required.  Interestingly, the authors find that all the studies advancing this hypothesis, based on the relationship between the breeding success of males and the number of dummy nests they built, involved species that were polygynous, that is the males having more than one mate.  (House wrens can be polygynous.)  Such animals would, as a matter of course, build more than one nest.  Perhaps, they speculate, through natural selection this behavior has become "exaggerated."

The authors conclude that the signaling hypothesis is "logically plausible."  But they suggest that alternative signals - singing or courtship feeding - could have potentially greater potential payoff requiring less investment.  Singing is a signal that reaches a broader audience and area than does an array of dummy nests.  More than multiple nests, courtship feeding is an immediate and direct indication of an attribute critical to successful breeding.

They write:

This suggests that building multiple nests would be an inefficient mode of signalling.  However, if non-breeding nests do act as signals, this inefficiency could explain why it is seen in so few species.

I suggest that some other kind of signaling might be going on, a possibility looking back to the territorial explanation that the authors say has been dismissed.  The wren might be making effective use of its thuggish reputation to warn other birds, perhaps other wrens included, that they better not encroach on its territory.  I came across this idea in the discussion of dummy wren nests in Sialis, the nice website devoted to bluebirds that Bet Zimmerman Smith maintains.  She "guesses" that non-wren species might recognize the dummy nest as the work of the aggressive house wren and decide it would be better to nest elsewhere.

Fledgling Shelter  This third of the current hypotheses is given short shrift by the authors.  Though non-breeding nests might at some point serve as shelter, they are built early in the breeding season, well before there are fledglings needing shelter.  In fact, given how poorly many of them are made, they are likely to be in serious disarray by the time fledglings might want to make use of them.  (This doesn't apply to bird boxes that might provide shelter regardless of the state of any nest inside.)

Nest Usurpation  The authors spend little time with this hypothesis which is advanced by only a single study.  This hypothesis contends that dummy nests might be part of defending against other bird species taking over a nest or might serve as quick replacements when a nest is overtaken.  One logical limitation to this hypothesis is that backup nests are useful only if the usurpation occurs during the female's egg-laying period.  Otherwise, the couple, whose nest is taken over, will have no immediate need for a backup nest.  The female will need time to become biologically ready to conceive and lay eggs again, time that would allow for building a new nest.

Two takeaways from the Macqueen and Ruxton literature review:  we don’t have conclusive evidence explaining why birds build dummy nest, and all current hypotheses, to one degree or another, have logical limitations.

The authors do characterize the hypotheses as “non-exclusive” which means that aspects of more than one might be at work.  As a result, it may not be a matter of accepting one and rejecting the others, but understanding that the behavior is complex, not easily explained, and the result of selection working through multiple avenues.  That would, I think, compound the difficulty of fashioning an appropriate research methodology to prove any explanation that is advanced.

Yes, this is complicated.

References

John James Audubon, The Birds of America:  From Drawings Made in the United States and Their Territories, 1841.

Hal H. Harrison, A Field Guide to the Birds’ Nests:  United States East of the Mississippi River, Petersen Field Guides, 1975.

Elise Isabella Macqueen and Graeme Douglas Ruxton, The Adaptive Function of Construction of Multiple Non-Breeding Nests in Birds, IBIS, Volume 165, 2023.

Margaret Renkl, The Questions Started With the Wren, The New York Times, July 7, 2025.

Bet Zimmerman Smith, Dummy and Abandoned Nests - Why Wasn't It Used?, Sialis.

The Surprising Story of Life on Earth

The inexorable movement of Earth’s tectonic plates, repeatedly creating massive continents and then tearing them apart, is an underlying plotline to the story of life on this planet.  Since the first appearance of life, a mere 100 million years after the birth of the planet 4.6 billion years ago, the influence of continental creation and destruction on the environment and, thus, on the fortunes of life has been profound.

In his relatively recent book, paleontologist Henry Gee, a senior editor at Nature, tells that part of the story well, but goes much further, painting with broad brush strokes a narrative of how life has evolved and survived, amid repeated extinction events.  The narrative he penned is informed and insightful, marked by humor and a steady stream of surprises.  This is a book that moves easily and quickly through the billions of years it covers.  Not for nothing did Gee title it:  A (Very) Short History of Life on Earth:  4.6 Billion Years in 12 Pithy Chapters (published in 2021).

Early on, he writes, “Perhaps the most amazing thing about life – apart from its very existence – is how quickly it began.”  (p. 5)  It strikes me that an ineluctable drive to exist undergirds life’s almost immediate appearance on the new planet, and that this also helps to explain why the history of life is the history of responses to change.  It’s a call and response pattern whereby life survives repeated episodes of devastation, episodes that Gee often ties to the creation of massive continents (e.g., creation of Pangea completed during the Permian) and to the breakup of those massive continents (e.g., breakup of Pangea beginning at the tail end of Triassic), all having profound effects on climate and habitable areas.

Evolution is part and parcel of this ebb and flow pattern.  Gee’s account offers up many examples of evolutionary change sparking still more change, all in the service of survival.  His narrative of the Cambrian is one of predator and prey engaged in a dance whereby new methods of attack spark new methods of defense which in turn . . . .   For instance, in the Cambrian, descendants of Saccorhytus (a very early enigmatic animal) chose not to build armor, but, instead, to evolve a means of escape though a “swishing tail.”  (p. 31)  This notochord would evolve into the spinal cord.  With the evolution of a spine came a cascade of changes, allowing animals to become more complex and bigger.  “All vertebrates are visible to the naked eye.”  (p. 36)  Of course, evolution doesn’t let a useful invention go to waste, and many vertebrates did evolve armor.

As I mentioned, Gee’s account is full of surprises.  One of the most startling, to me, was that of the import of the anus.  Who knew that the evolution of the anus in the Precambrian would have such far reaching effects?  He describes how plankton had simply let wastes flow everywhere out of their bodies, feeding oxygen-consumers in the water column.  But, once a discrete anus emerged “in some species of otherwise undistinguished worms,” the result was “a revolution in the biosphere.”  (p. 18)  In his telling, poop in concentrated packets was expelled from the anus and settled to the ocean floor, drawing the oxygen-consumers to the bottom, with the result that “the seas, once turbid and stagnant, became clearer and still richer in oxygen – enough to enable the evolution of larger life forms.”  (p. 18)

But, wait, that’s not all.  The anus in time lead to orientation to animals with a mouth at one end and an anus at the other, it became “a distinct direction of travel.”  And this led, eventually, to an arms race as animals began eating one another.  Yes, there is a leap there, but Gee is such a gifted writer that the reader, well, this reader, is happy to make that jump with him.

His is a very rich account of life on Earth, and it’s also idiosyncratic, each of its 12 chapters is centered on one or a few developments that, in Gee’s eye, are central to the broad portion of life’s history under review.  For instance, chapter 7, titled “Dinosaurs in Flight,” principally about the Jurassic and Cretaceous, is a wonderful exposition of the avian nature of dinosaurs. 

Flight, according to Gee, was in the works for dinosaurs from their beginning.

Dinosaurs and their immediate relatives spent millions of years accumulating everything needed for flight:  feathers, a fast-running metabolism, efficient air cooling to keep it under control, a lightweight frame, and a singular devotion to egg laying.  (p. 99)

Clearly, not all dinosaurs flew or kept flying once they did fly.  Flying is demanding of an animal’s physiological resources.  Notes Gee, it’s “an expensive habit . . . . so, it is not surprising that many flyers gave it up when the opportunity arose."  (p. 105)

Or consider that his chapter on mammals (succeeded by chapters that consider primates and then hominins).  Gee has embraced the view of mammals that I’ve expressed in this blog before (in the post titled Mammals All The Way Down, November 29, 2021) – they weren’t just biding their time in shadow of the dinosaurs, they were actively evolving.  Gee begins this chapter by discussing the evolutionary changes that equipped mammals with a hearing ability more sensitive than anything that had existed previously in vertebrates.  The physiological changes required to achieve this new level of hearing are, in Gee’s skilled telling, a product of complex evolutionary change repurposing bones.  Though mammals during the reign of the dinosaurs may have been away from center stage and, certainly, not the main act, they were evolving with gusto.  He stresses, “They were a venturesome bunch and not to be kept down.”  (p. 121)

After several chapters tracing the evolution of primates into hominins into humans, Gee ends with a final chapter (The Past of the Future) that leaves no doubt that ours is just a brief moment in the history of life on this planet and that we humans are fated to suffer the eventual fate of all life on the planet – extinction.  He writes:

Within the next few thousand years, Homo sapiens will have vanished. The cause will be, in part, the repayment of an extinction debt, long overdue. The patch of habitat occupied by humanity is nothing less than the entire Earth, and human beings have been making it progressively less habitable.  (p. 188)

He speculates on how the planet will change in the future and how life will be affected.  I was particularly taken by the humorous footnote he inserted covering the whole of this sobering exposition:

I should say that from this point onward, most of what I say is conjecture, or what scientist call making stuff up.  As someone once said, prediction is very hard, especially about the future.  (p. 268, footnote 17, note number appears on p. 189)

Bottomline, Gee posits that humanity won’t survive and all evidence of our existence, relative to the billions of years life existed on Earth will be negligible.  But, despite that lack of enduring legacy, or, actually, because of it, Gee counsels us that it’s important “to preserve what we have, to make our mayfly existence as comfortable as possible, for ourselves and our fellow species."  (p. 207)

This is an engaging, witty, and informative read.  I do have one quibble:  I think plants get short shrift in Gee’s telling of the story of life.  They’re not ignored, but the drama in his account has mostly to do with the trials, tribulations, successes and failures of animals.

Moveable Fossil Feasts

There are sites I consider moveable fossil feasts.  This is not in a Christian liturgical sense where the timing of a religious observation shifts from year to year.  Though a moveable fossil feast may, on occasion, exhibit some temporal impermanence, these feasts are much more about changing the locations of fossils.  Nothing divine about them, but, as a result of taking fossils from one site to another, likely more accessible, site, moveable fossil feasts offer collectors wonderful opportunities.

This terminology is mine alone.  I’ve never heard anyone refer to these sites in this fashion.  To be clear, I do not apply this term to places like the shoreline of the western Chesapeake Bay where fossils move as they erode from the Calvert Cliffs.  That process is natural.  In contrast, moveable fossil feast are human-made.  And, as such, the rewards they offer to fossil collectors are usually, but not always, a happy byproduct of the relocation of fossil-bearing sediment undertaken for some other purpose, such a beach replenishment.

This post offers brief descriptions of a few of the moveable fossil feasts with which I have some personal connection, either directly or indirectly, and one that I do not.  At the conclusion, I briefly highlight these sites' singular virtue and the challenging issues they raise.

North Myrtle Beach, South Carolina - A friend, sadly recently deceased, spent several weeks in different years vacationing with his wife at North Myrtle Beach, South Carolina.  They walked the beach a couple of times a day, outings timed with low tide.  As they went, they collected fossils – teeth, bones, shells – objects the waves had exposed on the beach.  A small sample from one year is pictured below.

These finds were often a stratigraphic and chronologic hodgepodge, a nightmare for identification.  Some came from the Pleistocene and Pliocene epochs (between 5 million to 11 thousand years ago), more from the Miocene period (23 to 5 million years ago) or the Cretaceous (143 to 66 million years ago).  Among the finds over the years were pieces of fossil turtle shells, ancient horse teeth, shark teeth, pieces of fossil sand dollars, and ammonite fragments.

My friend surmised this mixture resulted from efforts to replenish the beach, presumably with material dredged from offshore sedimentary layers from different time periods.  A competing or, perhaps, complementary explanation is that erosion of offshore sedimentary layers is the agent responsible for the fossils and their diversity.

C&D Canal (Reedy Point, Delaware) – I collected here twice many years ago.  It is a site created by the dumping of material dredged by Army Corps of Engineers in 1980 as it deepened the Chesapeake and Delaware (C&D) Canal.  The fossil-rich material hauled to, and deposited at, this site came from the Mt. Laurel Formation, dating from the Late Cretaceous. 

Here is a view of the location on one visit more than 15 years ago.

What was practiced here was mostly surface collecting, practitioners wandering through the overgrown and exposed landscape, eyes focused on the ground.  It was actually very easy hunting, though it took some time before the objectives of the searching came into view.  Most abundant (and obvious) were the orangey, long, pointed belemnites, the calcitic skeletal remains from the tails of the Cretaceous squid, Belemnitella americana.  Oyster shells (Exogyra) were also common.  Pictured below are some of these fossils.  An amateur’s rather old guide to the fossils from the Canal is suggestive of what could be found.

Is this site still there, still accessible?  I don’t know.  One source stated some four years ago, that the Army Corps of Engineers was planning to do more dredging and pile the dredged material on this site.  Unfortunately, this “new” material was slated to come from a formation lacking fossils.  Another source simply says it’s closed.  Such is the fate of, at least, this moveable fossil feast.  

Aurora Fossil Museum, Aurora, North Carolina – Located near the Lee Creek Mine, a phosphate surface mine that, when it was open to collectors, yielded stunningly beautiful fossils, particularly those from the megashark Otodus megalodon.  The various Lee Creek fossils come mostly came from the Pungo River (Lower Miocene) and the Yorktown (Early Pliocene) formations.  Not unexpectedly, the areas where we could collect, when we permitted into the open pit mine, were not pristine, not as they were originally laid down, but, rather, we needed to figure out which formations might have contributed to the areas in which we were collecting.  For me, at least, that was not always clear.

Now, I don’t consider the mine itself to have been a moveable fossil feast because collectors went to where the fossils originated, albeit in strata that were highly disturbed by the mining process.

No, the moveable fossil feasts, for me, are the spoil piles of material hauled from the mine and deposited outside the Aurora Fossil Museum in Aurora, North Carolina.  Purportedly, this material consists of tailings from the Pungo River formation which, even if true, does not locate these fossils within the various units that make up this formation. 

When I was last there – some 15 years ago – this was the view toward the spoil pile where I hunted a couple of times, once when a trip to the mine was cancelled at the very last minute and once after a successful hunt at the mine.

The museum has evolved greatly since then and, among other changes, now has two pits of material from the mine.

The finds were small, though relatively abundant; searching on one’s knees was rewarded.  Here is a sampling of what turned up on one of my hunts through the spoil piles.

This moveable fossil feast is wonderfully accessible, located in a small town with parking just a short stroll away.  It’s all rather domestic as attested to by the cat who oversaw my activities.  (The cat may have had other intentions for the sand of the fossil pit.)

Bradenton Beach, Florida – The same friend who enjoyed the moveable fossil feast at North Myrtle Beach was vacationing one year at Bradenton Beach when he came upon this scene in a parking lot serving the beach.

Never inclined to ignore the possibility that fossils might be had, he explored these huge mounds of gray, phosphatic sand and discovered a true wealth of shells, most in fantastic condition.  He spent much of his vacation climbing up and down this sandy landscape, gathering shells.

These were, indeed, fossil shells because he learned that the sand had been hauled to this location from an area quarry which he concluded was the SMR Mine in Sarasota, making these fossils Pliocene, about 3.6 to 3.0 million years old.  Here are three beautiful specimens I obtained from him.

Though this moveable fossil feast was extremely accessible (in a parking lot, of all places), my friend searched these sandy hills quite feverishly because all of this material was slated shortly to be crushed to pave the parking lot.

Rotterdam Harbor, The Netherlands – This last moveable fossil feast, international in nature, was featured in Nina Siegal’s article titled On the Hunt for Mammoths which appeared on November 17, 2025 in the online version of The New York Times (print edition ran the article on November 19, 2025).  

This feast has features reflected in some of the descriptions I’ve already provided of such sites, but there is a remarkable attribute that sets this one apart, prompting me to think – “The Dutch know how to do this.”

In the article, Siegal describes how people are hunting for fossils along at the Maasvlakte 2 beach, on the harbor shoreline in Rotterdam, benefitting from a beach reclamation project – no, more like a beach construction project.  This beach is wholly constructed of sediment dredged from the sea floor of the North Sea, sediment roughly 2.5 million to 11,700 years old.  This sediment comes from what once was a steppe where megafauna animals lived.  As a result, the material used to build the beach contains the fossil remains of many land animals, such as woolly mammoths, woolly rhinos, and giant horses.  Sprinkled among these are fossils from invertebrates including sharks.

Now, here’s where it gets truly amazing.  What sets this moveable fossil feast apart from the others I’ve described so far is the incredibly well organized scientific support for the amateur fossil collectors who scour the beach.  In The Netherlands, these fossil hunters are permitted to keep their finds, but they are also encouraged to register them with the online Oervondschecker (“Primal Find Checker”), initiated by the Port of Rotterdam Authority and now maintained by the Naturalis Biodiversity Center.  (The default language on the site is Dutch, so having a browser translate the text is useful for some of us.)  As the website states:  “Every notification will be reviewed within a few days by an expert.  A find gets a provisional determination and an (estimated) time determination.”  Marvelous.

How does Naturalis do that?  Each collector seeking to register a find is asked to submit pictures of it with the precise GPS location of where it was found (ah, the wonders of the smart phone) or, at a minimum, they are advised to use the app to locate the find on its associated map of the beach.  As the Naturalis Biodiversity Center explains on the website, the dredging operations were “accurately tracked,” including the depths at which the sand was “sucked up” during each trip.  Data on the geologic origins of the individual layers of sand at the seabed in the North Sea feed into the Naturalis calculations.  Further, where the dredged sand was deposited on the beach was also meticulously followed.  As a result, the general provenience of a find can be determined and used to estimate its age.  That is truly amazing.

In conclusion, my descriptions of these few moveable fossil feasts suggest a cardinal virtue as well as a couple of sins associated with them.  The single most important positive attribute of these sites is that, as a result of human intervention, fossil-rich sediment has been moved from one location to another, a place that is typically much more accessible and convenient for collecting.  Fossil hunting at them can be easy – e.g., going through the Aurora Fossil Museum fossil pits or walking the beach at the Rotterdam Harbor.

On the other side of the ledger, these sites have certain downsides.  Having separated sediment from their original location, the makers of these sites (with the important exception of the Rotterdam Harbor beach) sever the ties between the fossils and the geological strata where they were originally found.  Identification and age determination can be difficult, and sometimes, though not always, impossible – the finds on North Myrtle Beach, for example, are a challenge.  Another key negative attribute is that they can be transient, sometimes offering only a limited opening for collecting - the material in the Bradenton Beach parking lot is a striking case in point.

Still, they are a wonderful phenomenon and taking advantage of them, no matter the challenges, is a delight.