On the 11th Day of Ichnology, My Island Gave to Me: 11 Plovers Probing

As mentioned in yesterday’s post, I will be celebrating the traces of the Georgia barrier islands over a 12-day period approaching the holidays (you know: Winter Solstice, Christmas, Kwanzaa, Boxing Day, and New Year’s). To keep it relatively simple, each post will be about traces from a Georgia barrier island depicted in a single photograph, followed by my pithy descriptions and trenchant analyses, which may be accompanied by witty asides (or not). Today’s topic is on the feeding traces made by those cute little shorebirds, semipalmated plovers (Charadrius semipalmatus).

Plover-Tracks-ProbesSeimpalmated plover (Charadrius semipalmatus) tracks and probe marks made by their beaks on a sandy mudflat of Sapelo Island, Georgia. See the differences between the fresher probe marks versus the older ones? And what made those really tiny holes? (Photograph by Anthony Martin.)

Plover tracks in general show just three toes registering (no rear toe impression), are asymmetrical with an acute angle between the inner two toes, and have some webbing between the outermost two toes. If the toes were completely webbed, like that of a duck or goose, the foot form would be called palmate, but because it’s only semi-webbed, it’s called, well, I think you get it.

Although I didn’t see the birds making these tracks and probe marks, I’m fairly sure they were done by semipalmated plovers – rather than other species of plovers – based on tracks sizes and the commonness of this species on the Georgia coast. (What’s the scale? My finger is about 2 cm (0.8 in) wide, and don’t worry, it’s just my index finger.) These birds either walk fast, run, or stand still when they’re on the ground, and about the only reasons they have for standing still are to eat. The spacing between their tracks can act as an informal speedometer, with short spaces corresponding to walking and longer ones to running.

OK, so I identified the trackmaker, which means we’re done with all of that bothersome thinking stuff and we just end this post now, right? In a word, nope. It’s time to apply the awe-inspiring wisdom and power of ICHNOLOGY to this photo.

The combination of tracks and probe marks here, along with the teensy-weensy holes on the surface (did you just now see those?), give us insights on why the plovers were there in the first place. The tiny holes are probably made by the siphons of small clams: notice how some of them are paired, a typical pattern caused by incurrent (inhalant) and excurrent (exhalant) siphons for bringing in and pumping out water, respectively. The plovers were probably hunting these clams at low tide, along with any other yummy invertebrate treats they might have found once they stuck their beaks into someone’s business.

Notice also how the probe marks vary considerably in their diameters. This is a result of the plover finding its prey on the first try, or having to insert its beak several times to seek out their meals; the latter caused overlapping probe marks and a small depression. In some instances, these depressions collapse and form not-so-clear evidence of shorebird predation. Take another look at the photo: how many “old” feeding probes do you see now?

So if you’re a geologist looking at rocks of the right environments and ages for containing the traces of shorebirds – basically from the Early Cretaceous Period (~120 million years ago) onward – don’t just get all proud of yourself for just finding their tracks, slapping a name on those tracks, and dashing off a paper to your favorite journal. Look again for probe marks with those tracks, collapsed probe marks, and traces of those little invertebrate morsels that might have attracted those birds to that place, and then. There’s some little, once-breathing lives preserved in those rocks, wanting you to probe below the surface and learn about more about them.

Further Reading

Semipalmated plover. National Audubon Society.

Semipalmated plover. Cornell Lab of Ornithology.

Charadrius semipalmatus: semipalmated plover. Animal Diversity Web, University of Michigan.

Life Traces of the Victoria Coast: Australia’s Oldest Bird Tracks

The track seemed familiar, like a face I had seen before but couldn’t quite identify. Then I realized who it belonged to, and where I had seen many others like it. It was a bird track, remarkably similar to those in the sands and muds of the Georgia coast, made daily by the herons, egrets, and shorebirds. The other two tracks near it were similar in size and shape, but not nearly as evocative as this one. This footprint conjured an image of a bird slowing its descent from flight, then abruptly halting, planting its feet on a moist, sandy surface.

Modern-Fossil-Bird-Flight-TracksFootprints of flying birds, separated by 10,000 miles and more than 100 million years. The track on the left is from a great egret (Ardea alba), which landed on a hard-packed fine-grained sand of a coastal beach on Jekyll Island, Georgia. The track on the right is from a similarly sized bird that landed on a moist, loose fine-grained sand of a polar river floodplain during the Early Cretaceous Period, in a place now called Dinosaur Cove, Victoria, Australia. Oh yeah, it’s also one of two of the oldest bird tracks in Australia. (Both photographs by Anthony Martin; each track is about 10 cm (4 in) wide.)

Except this track was from a vastly different time, place, environment, and climate from the modern-day Georgia coast. It was fossilized in an Early Cretaceous (105-million-year-old) sandstone and collected from the coast of Victoria, Australia, at an auspiciously named spot called Dinosaur Cove. Because Australia was close to the South Pole then, this track and the other two near it were made in a polar environment. The environment was not coastal, either, but the sandy floodplain of a river valley shaped by melt-waters that flowed with each spring thaw.

Even more incongruously, I first saw this track and its petrified companions in the basement of Museum Victoria in downtown Melbourne, Australia, a thriving, cosmopolitan city of more than 4 million just outside the quietude I was experiencing then. Mentally and physically, I was about as far away from the Georgia coast as I could be, rendering the track’s familiarity both jolting and eerie.

Cretaceous-Bird-Track-LRA closer look at this fossil track, made by the right foot of a descending bird about 105 million years ago. Try to match the following verbal description with what you see here. (Photograph by Anthony Martin; scale to the left in centimeters.)

It had four thin toe impressions, like a slightly askew “peace” sign, with three forwardly pointing and spread widely, and one pointing behind. A linear claw mark – nearly as long as the three-toed part of the footprint – corresponded with the rearward-pointing toe, which had also left a faint impression. Sand piles only millimeters high were in front of the other three digits; another small mound of sand in the center toe impression was neatly bisected by a claw mark from that digit. This central claw mark was a trace of its next step, in which it pushed against the sand with the bottom of its foot and cut through the resulting hillock as its foot retracted. The forward toes made for a foot length slightly greater than the fingers on my hands, so it was about the right size for a small heron- or egret-like bird.


A more analytical look at this track. (A) Photograph showing how it looks on the sandstone surface, along with some of the little hills and valleys associated with it. (B) Interpretative drawing, showing: each digit, labeled from I (hallux) to IV; an approximation of the foot’s overall form (gray outline), the structures around and in the track, the main direction of movement by the foot as the bird landed (big arrow), and the direction of movement taken by that foot in its next step (little arrow). (Both photo and drawing by Anthony Martin; scale bar in both figures = 5 cm (2 in).)

The long, linear claw mark behind most of the track was the primary clue to both its identity and behavior. This was from a hallux, which in humans is our “big toe,” (digit I). But in birds, it is the backward-pointing toe of those that perch, a trait that better allows them to grasp branches in trees. Earlier that year (2011), I had told Tom Rich – a vertebrate paleontologist at Museum Victoria – that the thin-toed theropod dinosaur tracks we discovered in rocks just east of Dinosaur Cove in 2010 were likely not made by birds because they all lacked this identifying feature. Although Cretaceous bird tracks identified elsewhere in the world (Canada, the U.S., Korea, and China) do not always have a hallux, its absence makes it much more challenging to separate these tracks from those of similar looking non-avian dinosaurs.

Yet it was not just the hallux impression that convinced me of its identity, but its lengthiness. This mark was not a mere anatomy lesson, but also a window into what that bird was doing one day 105 million years ago, which was flying. The then-soft, wet sand had been sliced by the sharp claw on the hallux, which contacted the sand first before the rest of the foot registered. As this toe slid forward and stopped, the other digits came down, and forward momentum caused their leading edges to push against the sand, mounding it in front of these toes.

For those of you who saw my previous post about modern bird landing tracks (here), you probably watched this slow-motion video of a sparrow landing and taking off, and you probably watched it twice, because it’s just so stunningly beautiful. Regardless of whether you’ve watched it or not, view it one more time, then look at my interpretative drawing below to see how the same landing movement can be applied to a larger, heron-sized bird, and in a moist sand.

Cretaceous-Bird-Landing-Track-LRIn this partly interpretive, partly speculative drawing, I’m trying to show how the right foot of a heron-like bird, combined with its behavior and a wet, sandy substrate, could have caused the primary features in the Early Cretaceous bird track from Dinosaur Cove. Because the left footprint is not preserved in the rock, I’m assuming that it landed ahead of the right foot. As a result, it is shown here not quite landing, just a fraction of a second behind the right foot, and only represented in my mind by an imagined shadow. So what’s with the feather? Hey, I’m an artist, too. Feel free to find your own meaning in that, preferably aided by bongos.

Based on my years of experience with Georgia-coast bird tracks, the qualities of this fossil track were consistent with those in tracks made by similar-sized birds – such as small herons or egrets – that landed after flight. Ichnologists call such traces volichnia (= “flight traces”), which are rare in the fossil record, but abundantly represented in soft substrates today wherever flying birds might live. Some of the most evocative of such traces are left in snow, such as those made by owls preying on small mammals, but look closely for them on beaches or river floodplains, and you will find them. Volichnia thus neatly answer the oft-asked question: why do birds’ tracks suddenly appear?

Egret-Landing-Tracks-2Close-up of great egret tracks made by landing on a hard-packed beach sand, Jekyll Island. Both feet left long hallux claw impressions, although in this instance the left foot preceded the right when landing. (Photograph by Anthony Martin, scale in centimeters.)

Tricolored-Heron-Landing-2Close-up of landing tracks of a tricolored heron (Egretta tricolor) on a looser, moister, fine-grained sand in the back-dune area of St. Catherines Island, Georgia. The substrate conditions for these tracks are much closer to original ones for the Victoria tracks than those of a hard-packed beach sand. Notice how the hallux claw impression in the left foot is longer than the one on the right foot, which only shows up as a dot. (Photograph by Anthony Martin, scale in centimeters.)

I described bird-flight tracks in my book Life Traces of the Georgia Coast (pages 386-391) in a section where I advised paleontologically inclined readers to apply and test these criteria with fossil bird tracks. But with these tracks from Victoria, I was unexpectedly following my own advice, a situation that encourages uncomfortable feelings in scientists who tend to be overly self-critical of their work (guilty as charged).

Moreover, at the time I was looking at these and the other two tracks (July 2011), my book had not been published yet, nor had I ever written or published any peer-reviewed paper on bird tracks. Sure, I’m an example of what Malcolm Gladwell wrote about in his book Blink, an expert who had a minimum of 10,000 hours of field experience backing up my intuition (a number that, quite frankly, he must have pulled out of his cloaca). Backing up this intuitive and experience-based conclusion, however, posed a huge challenge, like a fledgling trying to decide whether it was time to leave its nest and take a test flight. It’s not the ill effects of possible free-fall to fear, but the predators waiting to pounce on an avian-ichnological novice like myself.

Frustratingly, though, the rock holding these tracks lacked any other evidence of that next step, as well as the other foot. The track was of the bird’s right foot. As seen in the previous photos, volichnia made by landing birds have paired footprints, right and left together but slightly offset, and with either the right or left foot behind the other. But the slab of rock had no track behind this right-foot impression, and it was broken along the front edge of the middle digit. If this bird had landed with the right foot first – which I think it did – then the left foot would have been more than a track length ahead of the right. If so, it may be gone forever, taken by the same coastal erosion of the Victoria coast that gave its discoverers the surviving tracks, who arrived just in time to save them.

How were these tracks found? Not by me, that’s for sure. They were discovered by the invaluable, indispensable, and intrepid allies of desk-bound, exam-grading, lab-teaching, and meeting-imprisoned paleontologists everywhere: volunteers. On November 29, 2010 – almost three years ago – Museum Victoria volunteers Sean Wright and Alan Tait were at Dinosaur Cove, scouting for bones along its rugged, rocky shore. The name for this place was not bestowed on it because it resembled a Stegosaurus or some other pareidolia, but because it was the same place where most of the dinosaur bones known in Australia were found and recovered.

Excavated during the 1980s-1990s, Dinosaur Cove – which is about a three-hour drive west of Melbourne – was among the most logistically difficult dinosaur dig-sites in the world, as described by Tom Rich and Patricia (Pat) Vickers-Rich in their book, Dinosaurs of Darkness (2000, Indiana University Press). It and another site about a two-hour drive east of Melbourne, Dinosaur Dreaming, have resulted in the most complete assemblage of polar-dinosaur bones in the Southern Hemisphere.

Thus Wright and Tait were not searching randomly along the coast, but were looking for rocks that might contain fossil bones that had eroded out of the coastal outcrop. Instead of bones, though, Wright spotted the three-toed patterns of fossil tracks in a slab of rock amongst the boulders and cobbles in the surf zone. With this discovery, Dinosaur Cove was suddenly and inadvertently added to a very short list of Cretaceous vertebrate tracksites in southern Australia.

Tait-Photo-Dinosaur-Cove-TracksThe slab of rock with the oldest known bird tracks in Australia. The two on the right we diagnosed as from birds, whereas the one on the left is probably a mere non-avian theropod track. (Photograph by Alan Tait.)

At the time, Wright and Tait figured these were probably fossil footprints of dinosaurs, such as theropods or ornithopods, both of which make three-toed tracks. When Tom e-mailed me photos of the tracks, I confirmed that they were tracks, and that they looked a lot like the theropod-dinosaur tracks I had described from rocks of the same age from Milanesia Beach, about 9 kilometers ( 5.5 miles) east of Dinosaur Cove.

About four months later, on March 31, 2011, Tait went back to Dinosaur Cove with some hand tools and a backpack, and broke the slab into four large pieces so they could be transported on foot: which he did, and with all 45 kg (100 lbs) on his back. For anyone who has hiked into and out of Dinosaur Cove – which I have several times – this was a remarkable one-person recovery effort, one that some people might term as “crazy.” But this craziness paid off big time.

The bird tracks had also come in for a landing a second time on the rocky shore of Dinosaur Cove, having fallen off the outcrop as a consequence of coastal erosion. Tom recognized the rock as coming from a sandstone bed just above the Slippery Rocks Tunnel site, where he, Pat, and many volunteers dug, broke, blasted, sifted, cursed, and otherwise labored in their quest to collect the dinosaurs there.

Tait-Photo-Dinosaur-CoveThe Slippery Rocks Tunnel (SRT) site, where what was originally the greatest number of polar dinosaur bones in the Southern Hemisphere were found in the 1980s-1990s. The arrow shows where the slab holding the tracks was located until Alan Tait took it out of there and to Museum Victoria. The probable source bed (SB) for the tracks is just above the tunnel. (Photograph by Alan Tait, taken on November 29, 2010, the day the tracks were discovered.)

Dinosaur-Cove-WrightAnother look at where the tracks were discovered, but from the other direction (looking west). I’m not sure if that’s Alan Tait in the photo and it was taken by Sean Wright, or whether it’s Sean Wright and the photo was taken by Alan Tait. Anyway, check out all of those Cretaceous rocks!

Great discovery, huh? Obviously, it was time for us to contact the press and breathlessly report that we had the oldest bird tracks in Australia. Except that, no, that would have been totally wrong, and would have served as a great example of how science is not done. This had to go through peer review, which meant that no matter how confident I might have been about their identity, they’re being described in a peer-reviewed publication and acceptance by the rest of the paleontological world was not guaranteed. So I asked Pat Vickers-Rich and Tom Rich to coauthor it, and was delighted when they accepted; sedimentologist Mike Hall of Monash University later joined us as a co-author, too.

Figure-2-DraftThe broken slab of rock found by Sean Wright and Alan Tait at Dinosaur Cove, then taken out of there by Alan Tait, but now in its final resting place, the basement of Museum Victoria in Melbourne, where it’s been given a specimen number. Tracks ! and 2 (T1 and T2) are interpreted as bird tracks, whereas the one on the far left (T3) is probably a non-avian theropod dinosaur track. The arrow shows where the rock was sampled for describing the nature of the original sediments. What do I really love about this discovery?  That the theropod-dinosaur track is the ho-hum and so-what part of it. Take that, non-avian theropods! Birds rule!

To make an already long story much brief, a year-and-a-half went by before the paper was finally accepted and published in the journal Palaeontology last Friday. Peer review on this paper was tough, and among the most challenging I’ve faced in my career. Different versions of the paper went through two rounds of review with four different reviewers, two of whom were anonymous, and two of whom were not (thank you, Matteo Belvedere and Jenni Scott!). I almost gave up on it several times, having been so discouraged by negative comments that I overlooked the most affirming part, which was this: all of the reviewers agreed we had bird tracks, and that they were the oldest known in Australia. That kept me going.

Notice I said “tracks,” as in plural. A great benefit of the sometimes-demoralizing scrutiny provided by these reviewers was that most pointed to the track just left of the “landing” track and said, there’s another one. Although I originally thought it was from a non-avian theropod, they were correct: this was from a bird’s left foot, and one with a foot close in size and form to the other one, although it had a much less obvious hallux impression. One of the more interesting traits of this track, too, was how one of its digits flexed as the foot moved against the sand, leaving a curved impression.


Close-up of the other large bird track on the same surface and close to the first one. Although I don’t think this one represents flight – just walking – it was the right anatomical traits for a bird, including that hallux impression on the lower right side. (Photography by Anthony Martin, scale in centimeters.)

The third track presented a dilemma, as it had qualities of a thin-toed non-avian theropod track – think something like an oviraptorid or ornithomimid – but easily could have been that of a bird, in which its hallux didn’t register on the sand at the time. So we concluded that it was probably from a non-avian theropod, but are open to the possibility that it was from a bird, too.


The third track on the slab, which we interpreted as the right footprint of a non-avian theropod dinosaur. It also probably represents a double print, where the foot registered twice and distorted its features a bit. This track is also very similar to theropod tracks identified from rocks of the same age at Milanesia Beach, which is about 9 km (5.5 mi) east from Dinosaur Cove on the Victoria coast. (Photograph by Anthony Martin, scale in centimeters.)

Could we all be wrong, and none of these tracks are from birds, but from some theropod dinosaurs that were very close to birds in their foot anatomy? Sure, that’s possible, but not likely at this point. Could I be wrong about taking one track and interpreting it as evidence of flight? Again, that’s possible. Alternate explanations include that the bird just hopped – perhaps with a flap or two – before landing. Or its foot just slipped on the wet sand as it was walking forward. However, in my experience with modern birds, such tracks are even more rare than volichnia. Could Cretaceous birds in polar Australia have been more clumsy than those today, hence their slipping tracks would have been more common? OK, now that’s just silly. Let’s just celebrate this find for what it is:

  • The oldest known bird tracks in Australia.
  • The only Early Cretaceous bird tracks in the Southern Hemisphere.
  • The presence of fair-sized birds (herons or egrets) during the Early Cretaceous in a polar environment.
  • Evidence for flight in an Early Cretaceous bird track, one of the few examples known in the world.
  • The first vertebrate tracks known from Dinosaur Cove, a place previously famed for its dinosaur bones.
  • The first dinosaur track from Dinosaur Cove.
  • More evidence for Early Cretaceous birds in Australia to supplement the few bones that have been found thus far, including only a single furcula (wishbone) from Victoria.

All in all, it might just be three fossil tracks, but those three tracks just made the fossil record for the birds on an entire continent and the rest of the Southern Hemisphere just a little bit better. So now that they’ve landed, let’s allow our imaginations to take off, and go find some more.

Acknowledgments: My coauthors, Tom Rich, Pat Vickers-Rich, and Mike Hall; Sean Wright and Alan Tait; David Pickering and Rod Start at Museum Victoria; the Center for International Programs Abroad for transportation to and from Australia; my wife Ruth Schowalter for encouraging me during the 1.5 years of agonizing over the research; and of course, the tracemakers, avian and non-avian, who truly made the research possible by leaving tracks on that floodplain 105 million years ago.

Pertinent Links:

Martin, A.J., Vickers-Rich, P., Rich, T.H., and Hall, M. 2013. Oldest known avian footprints from Australia: Eumeralla Formation (Albian), Dinosaur Cove, Victoria. Palaeontology (published online October 25, 2013): DOI: 10.1111/pala.12082

ABC Science Show, October 26, 2013: “Fossilised Dino Bird Tracks 105 Million Years Old,” reported by Sharon Carleton.

Emory University Press Release (Eukekalert): “Tell-tale toes point to oldest-known fossil bird tracks from Australia.” (By Carol Clark, Emory University)



Why Do Birds’ (Tracks) Suddenly Appear?

Among my favorite tracemakers of the Georgia barrier islands are birds, a fondness inspired by their great variety (more than 200 species), numbers, and diverse behaviors. But if pressed to name my absolute favorite types of bird traces, I would not hesitate to say “flying tracks.”

Egret-Landing-TracksTracks from a great egret (Ardea alba) on a hard-packed beach sand that say, “I just flew in, and boy are my arms tired.” Notice the offset right-left tracks, long scratch marks left by claws on the rear toes, and cohesive bits of sand pushed forward by the egret’s feet when they contacted the sand. (Photograph by Anthony Martin, taken on Jekyll Island, Georgia.)

Now, “flying tracks” may sound contradictory, as a bird in flight leaves no tracks. But for those birds for which flight is an everyday habit, they take off and land, and many of these birds do so on the ground. This fact of avian life is recorded faithfully in the sands and muds of the Georgia barrier islands, and I have often delighted in encountering such tracks made by birds from sparrows to grackles to seagulls to pelicans to great blue herons. When covering this topic in my book (Life Traces of the Georgia Coast, just in case you needed reminding), I had to restrain myself from writing too much about it. Fortunately for readers, though, I described flight traces in enough detail there that I’m confident most people will be able to spot and recognize them. The following pictorial guide, most of which I showed during a recent talk to the Atlanta Audubon Society, should also help.

Sparrow-Flying-TracksFlight tracks of a small songbird (probably a species of sparrow) on coastal-dune sands, showing that it didn’t stick around very long: landing, a hop, then take-off. (Photograph by Anthony Martin, taken on Little St. Simons Island, Georgia.)

How to tell whether a bird was landing or taking off? Your first clue should be a blank area in mud or sand, which will be devoid of tracks just behind a bird trackway, or the opposite, a trackless place just beyond the last footprints. In both instances, tracks are normally paired (side-by-side). For example, here’s an entire sequence made by a common ground dove (Columbina passerina), from landing to walking to take-off.

Ground-Dove-Flying-TracksEntire landing, walking, and take-off sequence for a common ground dove (Columbina passerina) in back-dune area. Notice how it avoided the ghost-crab burrow by walking around it just before deciding to exit the scene. (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

Ground-Dove-Landing-TracksClose-up of landing tracks, in which this ground dove came in from the right, then shuffled its feet to shift direction to its right. (Photograph by Anthony Martin.)

Ground-Dove-Takeoff-TracksClose-up of take-off tracks, where this ground dove was walking normally, then put its feet together and did one of its typically instant take-offs. (Pro-ichnologist tip: the scratch marks to the right are ghost crab tracks, not wing impressions.) (Photograph by Anthony Martin.)

Look closer at potential flight tracks and you will see other details that tell you whether a bird was coming down to earth or bidding the ground goodbye. Landing tracks often have long impressions behind them, “skid marks” that show how the bird decelerated and controlled its fall through a combination of body positioning and calculated flapping.

For larger birds with a backwards-pointing toe (hallux) – such as herons or egrets – these tracks usually leave a lengthy scratch mark from the claw on that foot. While landing, one foot plants in front of the other – either as an offset right-left or left-right pair – and the first track normally has the longer scratch mark. Either footprint also may have some mounding of mud or sand in front of it, as the forward momentum of the bird exerted pressure against whatever medium it encountered.

Egret-Landing-Tracks-2Another look at those great egret landing tracks shown previously, but now probably understood a little better through the power of words combined with images. ¡Viva Comunicación de la Ciencia! (Photograph by Anthony Martin.)

Flight-Trace-EgretClose-up of that great egret’s right track, with features showing how its foot slid across the beach surface as it slowed its descent, then stopped. (Photograph by Anthony Martin.)

In the following video of a sparrow both landing and taking off, watch how it points its rear claws toward the surface as it approaches, then make first contact, followed by the forward-pointing toes. Also notice how one foot barely precedes the other, which in its tracks would should up as a very slight offset between the two. (Warning: This video is exquisitely beautiful, and is best watched with mouth agape in wonder.)

Depending on how fast a bird came down, and taking into account lots of other factors (for example, wind direction and speed), this landing pattern could be followed by a hop, or it could just segue into a normal diagonal walking pattern. Also keep in mind that birds with small or absent halluces (plural of hallux) and full webbing between their toes – such as gulls – may just show their forward three digits skidded, leaving no claw marks in the rear part of the tracks.

Gull-Landing-Hop-SapeloLanding tracks of a laughing gull (Leucophaeus atricilla), in which it first skidded, but must have had enough forward momentum to keep it going forward with a big hop. (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)


Close-up of a different set of landing tracks from a laughing gull with nicely defined skid marks on both feet. (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

Take-off patterns involve opposite movements, in which the feet come together, but the digits dig in and push off, leaving scratch marks from the claws and well-defined mounds of sand or mud behind the digits, instead of in front of them. They can also be quite ungainly: I’ve seen pelican and vulture trackways in which they either run or skip for five-six steps before they were aloft, with increasing distances between each successive set of tracks. But sometimes a large bird like a pelican can impress me with its tracks, showing where it successfully accomplished a sudden take-off from a standing start.


Take-off tracks of a brown pelican (Pelecanus occidentalis) in which it must have flown from a standing start. Also note the water-drop impressions in front of the tracks, indicating that the pelican had just been in the water and still had wet feathers when it took off. (Photograph by Anthony Martin, taken on Sapelo Island, Georgia.)

So given these search images, lots of birds, and blank canvases of coastal sand or mud, you should now be able to find and diagnose your own “flying tracks.” But you also don’t need to restrict your searches to beaches: these traces can be found wherever flying birds live and visit the ground.

Using such clues, could we ever apply them to recognize flying tracks from the fossil record? Why, yes indeed. And for those of you who read this fair, here’s your Easter egg. The contents of this post relate to a major scientific discovery that will be announced in a few days: you heard it here first. So look for that news to come in for a landing soon.


A Good Bird Track is Easy to Find: Flannery O’Connor, Her Birds, and Their Traces

Authors of books are sometimes lucky enough to get people interested enough in both them and their books. Even better, these authors are sometimes invited to talk about their books to a receptive audience. Yet I’ll bet few authors get the opportunity to talk about their books with fellow book lovers while also standing on the front porch of a great American author. Even less probable is that the author of a natural history book – one related to paleontology, no less – would somehow have to relate his or her work to a deceased author best known for her Southern Gothic fiction.

It’s a sign! Upon my arrival at Andalusia Farm, the former home of Flannery O’Connor, this sign greeted me at the door, reminding me why I was there. It was fun to think that during Flannery O’Connor’s life, this is how she might have announced a lecture at her place, using a sheet of paper with words, posted on her door. (For the sake of imagination, just ignore that the notice was created and printed by person using a couple of 21st century devices.) Photograph by Anthony Martin.

This past Sunday, I was just so fortunate and challenged, having been invited to speak about my new book, Life Traces of the Georgia Coast, at Andalusia Farm, the former home of famed American writer Flannery O’Connor. Andalusia is located just north of Milledgeville, Georgia, and despite many previous trips to Milledgeville, this was my first visit to Flannery O’Connor’s former haunts. The house and grounds are in a formerly rural setting, its clay-laden driveway just off a busy highway and directly across from a chain hotel. Yet her house is still surrounded by more than 500 acres of forest, streams, and a pond; the pond is visible from the front porch of the house. These natural areas are what attracted me to coming, and provided an avenue for connecting themes of my book with this place.

A view of the main house at Andalusia Farm, where Flannery O’Connor spent more than a third of her life. Her bedroom, where much of her writing also happened, is just to the left after passing through the front porch. Photograph by Anthony Martin.

A sign telling about the recent history of Andalusia. Sadly, it does not include any mention of the Alleghanian Orogeny that contributed to the Piedmont Province there, nor does it inform visitors about the maximum extent of the Cretaceous and Eocene seaways just to the south, nor does it acknowledge the former presence and effects of the Pleistocene megafauna that used to live there. But I suppose all of that would have required a much bigger sign. Photograph by Anthony Martin.

O’Connor is much revered in the Southern U.S. and elsewhere, a loyalty that stems partly from the fact that she was indeed a terrific writer of Southern-inspired literature – consisting of short stories, novels, and essays – and partly from a wistful longing of “If only”: namely, if only she had lived longer. Born in Savannah, Georgia in 1925, she traveled to what was then called State University of Iowa (now the University of Iowa), where she earned an MFA, and soon afterwards began her illustrious writing career. In 1951, she was diagnosed with the same disease (lupus) that killed her father while he was still relatively young. She lived with this debilitating condition for the next 14 years, the last 12 of which were at Andalusia. She was only 39 years old when she died in 1964.

So how did I become a character in a Flannery O’Connor story? I blame it all on a paleobotanist friend of mine at nearby Georgia College and State University, Dr. Melanie DeVore, who suggested to me several years ago that I come to speak at Andalusia about my upcoming book. “Why?” was my first response. After all, as a long-time resident of Georgia, I was embarrassed to admit that I had read very little of O’Connor’s works until just recently. I also could not figure out how the plant and animal traces of the Georgia barrier islands could be related to a Southern author whose home was just above the fall line, between the Piedmont and Coastal Plain provinces of Georgia. Even the Cretaceous seaway from 70 million years past had not washed onto the landscape of O’Connor’s home. Thus I felt hard-pressed to come up with a way for my book to be relevant to her literary contributions and a sense of place.

Still, Melanie continued to encourage me to think about it. Admirably enough, she was trying to find ways in which natural scientists might contribute their perspectives to the considerable scholarship behind O’Connor’s works and the popular appeal of her former home. So I delved into O’Connor’s biographies, and searched for an ichnological connection between what she did and my interests. This is when I found the key, the theme that united: birds.

It turns out that O’Connor was a great lover of birds, and the thought that perhaps she had too many birds never occurred to her during her last years at Andalusia. Peafowl were her favorites for many reasons, some of which she explained ever-so-eloquently in several essays, including one of her most well-known works of non-fiction, The King of Birds. Domesticated birds also abounded on her property, including chickens, ducks, geese, and swans, all part of her avian menagerie. At one time, she evidently owned more than a hundred peafowl, a daunting number when one considers the vociferous qualities of these birds.

A peacock in a spacious enclosure just outside of Flannery O’Connor’s home, graciously displaying his tail feathers for us. See those feet? We’ll take a closer look at those soon. Photograph by Anthony Martin.

One of two peahens in the same enclosure, not nearly as resplendent and gaudy as her male companion, but still a very attractive bird. Of course, I was looking at her feet too, thinking about the tracks she would make, and how these might differ from those of the peacock. Photograph by Anthony Martin.

O’Connor’s earliest few minutes of fame were also bird-related, and established her life-long association with oddities of the South. When she was only five years old, she somehow taught a chicken to walk backwards. This feat attracted a film-reel company (Pathé News), which sent a crew from New York to Georgia to record this atypical avian mode of locomotion. The film reel, shown in theaters in 1932, also parodied O’Connor’s childhood accomplishment by reversing the film for other walking domestic animals, making these animals also appear to also walk backwards.


It’s one thing to read about Flannery O’Connor and her backwards-walking chicken, but it is another to actually see an original film about it. In the reel, she is mistakenly identified as “Mary O’Connor,” but no matter, as it was a start to her enduring fame for inventing quirky actions, plots, and characters reflecting the off-kilter cultures of her Southern environs. Incidentally, just how would you tell the difference between tracks made by a chicken moving forward or backwards? Maybe that should be the topic of a future post…

O’Connor’s link to paleontology was an oblique one, in that (as far as I know) she did not express any interest in it as a subject. Nonetheless, she was a great admirer of paleontologist, Jesuit priest, and philosopher Tielhard de Chardin, and the title of one of her anthologies, Everything That Rises Must Converge (1965), came directly from one of his writings. Also, in an “if only” moment of my own during my talk on O’Connor’s porch, I wondered what sort of fiction or essays would have come out of O’Connor had she lived long enough to learn that birds are actually living dinosaurs, and hence she had unwittingly surrounded herself with the progeny of those Mesozoic monsters.

Oh yes, my talk on O’Connor’s porch. How did that go? Fantastically. Because of the gorgeous weather that day, Craig Amason, my host and executive director of the Flannery O’Connor-Andalusia Foundation, thought that we might hold the discussion on the screened front porch, rather than inside in one of the more spacious rooms of the house. I was all for this idea, partially for its atmosphere (I mean, how cool would it be to talk about Flannery O’Connor with some of her fans on her front porch?), but also because we planned to have everyone walk on the trails with us later, looking for tracks and other traces of the animals that live there. Melanie and I had already scouted the trails in the morning and found a few surprises, so we knew that part of the program would be great fun, too: might as well get them halfway outside already by being on the porch. Fortunately, all of the dozen or so people who showed up also approved of this plan, which was helped in no small part by a heaping helping of cookies and soft drinks, enticing them to stay right there on the porch for a spell, and perhaps even relax in a rocking chair.

Dr. Bruce Gentry of Georgia College and State University, having just bought a copy of my book, opens it to take a look inside. Dr. Gentry is a scholar of Flannery O’Connor works and heads the Flannery O’Connor Studies Program at Georgia College and State University, in nearby Milledgeville. Meanwhile, I’m in the background, gesturing grandly to the delicious cookies on the table next to me while also introducing everyone to the topic of bird tracks and sign. Photograph by Melanie DeVore.

A sample of our front-porch chat about Flannery O’Connor and her birds, in which I point out the close resemblance between a rooster’s feet and those of a peacock. Although the peacock tracks would have been noticeable larger than those of her chickens, their overall forms would have been nearly the same, with three long thin toe-prints pointing forward, one shorter one pointing backward, and all four ending with clawmarks. Video footage by Craig Amason, exceutive director of the Andalusia-Flannery O’Connor Foundation.

A close-up of a rooster’s feet. Think about the tracks this would produce, whether walking forward or backwards. Rooster was known as “Tom” (R.I.P.), formerly owned by Carol Ruckdeschel on Cumberland Island, Georgia. Photograph by Anthony Martin.

Now compare the rooster’s feet to those of this peacock at Andalusia Farm, and you’ll see for yourself how close they are to one another in their overall form, despite the rear digits being hidden in this photo. I could not help but think that O’Connor, while seeking the pleasure of the company provided by her birds, also saw thousands of similar-looking peacock and chicken tracks every day she went outside. Photograph by Anthony Martin.

The talk itself was mercifully brief on such a fine day, with tracks and other sign awaiting us. So I simply expressed my gratitude for being there with all of us gathered in this special place, talked about Flannery O’Connor’s love of birds, and jumped into a speculative discussion of what tracks she might have seen every day on the farm. My presentation was decidedly low-tech, in which my only visual aids were paper print-outs of bird tracks and feet and a couple of my illustrations from the book, which were of bird-track categories and nests. These were supplemented by my acting out birds motions (walking, mostly), demonstrating how these behaviors would result in certain trackway patterns. One of these, much to the amusement of audience, was of a peacock doing its little circular and sideways-stepping dance, which was followed by my asking them to imagine the trackway patterns that would have resulted from such courting.

I also did a short reading from my book that introduces the topic of bird tracks, which fairly drips with admiration for the complexity of behaviors captured by such traces, thus hopefully echoing O’Connor enthusiasm for birds. Many questions were asked and observations of bird behavior offered, a give-and-take that I thoroughly enjoyed in the role of a “guide on the side” rather than a “sage on the stage” (or a “torch on the porch”). Once done, we had a short break for people to buy my book (thanks, y’all!), then walked onto a nearby trail to look at what the wild animals had left us the previous few days.

This outing was enjoyable, a bit of a treasure hunt and an eye-opening experience for many of how much animal activity is embodied by their traces in a typical Piedmont forest and its water bodies. Some of the traces I had seen earlier in the day while out scouting with Melanie, but we saw more, such as previously missed raccoon tracks and woodpecker sign. The highlights included the discovery of fresh (less than 12-hour-old) beaver tracks on one of the stream banks. This delighted several people, who told me that beavers had supposedly moved out of the area years ago, so they were pleased to know that at least one was back in the neighborhood. I was also excited to find coyote scat on the trail, which inspired earthy, amusing comparisons between the territorial markings of mammals in the wild versus those of corporate board members and academics (which, not surprisingly, are not so different in practice).

Coyotes just can’t help themselves: where we see a human footpath, they see an advertising opportunity. Here I excitedly point out an example of coyote scat, which had been strategically placed in the middle of the trail so that all other mammals would know this was her/his territory. You know, just like you might see happen in a professional meeting. Photograph by Melanie DeVore.

Fresh beaver tracks on a stream bank! This was a happy find, as it demonstrated that at least one beaver was in the area, following a nearly five-year absence of their species. These tracks show the beaver turned to its right and walked down the bank and into the water; look for the large rear-foot track to the left, and the tail dragmark in the middle. Swiss Army knife is about 6 cm (2.4 in) long. Photograph by Anthony Martin.

Once this short, ichnologically-infused hike was over, people thanked me and bid goodbye, but a few of stayed behind to take a gander at the peafowl, which were in a large enclosure just behind O’Connor’s house. One male and two females are kept there, and our timing was impeccable, as the male was in full display mode, feathers fully erect and dazzling as he strut about the grounds, while the peahens stayed in the background, mildly impressed or nonchalant. (“Oh yes, he does that all of the time,” I imagined them thinking, mildly bored.) Nevertheless, as far as we non-avian bipeds were concerned, he was indeed the king of birds.

But that’s when my ichnologist hat popped onto my head, askance from its sudden appearance. Craig had told me earlier about the peafowls making a dust bath in the confines of their enclosure, and sure enough, there it was. It matched the width, depth, and shape of dust baths I had written about in Life Traces of the Georgia Coast, only for wild turkeys. Birds make dust baths for alleviating skin parasites, in which they hunker down in them, using their wings to distribute enough fine-grained sediment on them to smother the offending lice or other arthropods. Could such traces preserve in the geologic record, whether they were made by feathered dinosaurs, birds, or mammals? How could we recognize or distinguish these from other shallow depressions? And most importantly, did Flannery O’Connor ever see such dips in the landscape, and if so, did she know their meaning?

A dust bath made by peafowls, about 50 cm (20 in) wide on its longest dimension, and looking a little less dusty after several days of intense rain the preceding week. Still, this was a cool trace to see, and conjured some imaginative thoughts about these as trace fossils. (Peafowl feces extra in the pit: no charge.) Photograph by Anthony Martin.

Another ichnologically inclined thought occurred to me while there at the enclosure, and is worthy of further experimentation. How might we tell the male (peacock) tracks from those of the female (peahen)? Take a look at the following photo, and you tell me. Anything there that might leave a distinctive mark identifying the gender of its tracemaker?

Here comes the groom! Any aspect of this tracemaker’s anatomy that might leave traces telling you he was a boy bird? Photograph by Anthony Martin.

So from this day trip to Andalusia Farm, I was awed, inspired, and ever slightly more enlightened by it all, and hoped that a small amount of the same feelings had been experienced by others who participated in this special day. Still, I was also humbled, realizing how little I still know about Flannery O’Connor, why she connected so well with birds, bird traces and behavior, or how these traces might manifest themselves to us and grace us with wisdom as recognizable trace fossils made in a distant past. Hence from my time there and into my future, I will endeavor to keep in mind the words spoken by Dr. Block, a character of O’Connor’s in The Enduring Chill from the anthology, Everything That Rises Must Converge:

“Most things are beyond me,” Block said. “I ain’t found anything yet that I thoroughly understood.”

Acknowledgements: Many thanks to: my good and long-time friend Melanie DeVore for encouraging me to visit Andalusia to share my science and sense of wonder; Craig Amason for being such a gracious host; Bruce Gentry for his continuing contributions to teaching his students about the complex and varied dimensions of Flannery O’Connor, a great American writer; the people who showed up and made for lively company; and of course the birds and their traces, which will outlive all of us, no matter the lengths of our lives.

Further Reading

Elbroch, M. and Marks, E. 2001. Bird Tracks and Sign of North America. Stackpole Books: 456 p.

Martin, A.J. 2013. Life Traces of the Georgia Coast: Revealing the Unseen Lives of Plants and Animals. Indiana University Press: 692 p.

O’Connor, F. 1955. A Good Man is Hard to Find, and Other Stories. Harcourt, Brace and Company: 265 p.

O’Connor, F. 1965. Everything That Rises Must Converge. Farrar, Straus and Giroux: 320 p.

Simpson, M. 2005. Flannery O’Connor: A Biography. Greenwood Books: 152 p.