Treading Ambiguously: Theropod Versus Bird Footprints

Hello, Dear Readers!

I'm back in the office full-time for the rest of the year, so as part of our promoting our science mandate, I have the opportunity to blog about some of the nifty cool science I've recently published. Here I'm going to talk about one of our newest papers, entitled Birding By Foot: A Critical Look at the Synapomorphy- and Phenetic-Based Approaches to Trackmaker Identification of Enigmatic Tridactyl Mesozoic Traces. Or, in other words, "How do I tell large bird footprints from small theropod footprints?"

We do a lot of work in the Early Cretaceous in British Columbia. By "a lot", I mean that the majority of our dinosaur and other vertebrate footprint localities are in Early Cretaceous (between about 145 million years old and 100 million years old - check out the Geological Society of America's latest timescale) sedimentary rock.

Exciting things were happening in Bird Land during the Early Cretaceous. More and more bird skeletons are being discovered from the Early Cretaceous every year, but most of these are not in North America. Recently, Wang et al. (2015) published on Archaeornithura, a small ornithuromorph bird capable of flight, from the Lower Cretaceous Huajiying Formation of northeastern China. The specimen is also beautifully feathered...except on the long legs, where feathers are conspicuously absent from the tibiotarsus and tarsometatarsus (lower leg). The equivalents on our bodies would be shin and long bones in our foot, but we mammals have a strange skeleton when compared to birds. Long, unfeathered legs strongly suggests a wading bird/shorebird lifestyle interpretation for Archaeornithura.

This piques my interest. In western Canada there is a pretty decent record of bird footprints from the Early Cretaceous. These footprints are from birds similar in habitat preference, shape, and size to our modern shorebirds and wading birds. When the skeleton of a flying (volant is the term used in scientific lit) Early Cretaceous bird that may have skittered along the shoreline is described, I get all chirpy-happy.

Looking pictures of the feet of Archaeornithura, a footprint from this animal would likely not be identified as anything other than a bird footprint: the foot is small (rough estimate of 15mm from the "heel" of the foot to the tip of the longest toe, digit III), and there is a well-developed hallux, or digit I that faces almost straight back from the foot. So far, so good. China's Early Cretaceous bird footprint record is amazing - and growing - so having a early shorebird skeleton gives us a potential trackmaker for one of these footprint types.

Identifying modern theropod tracks is fairly simple: we only have one group of theropods running and flapping about right now, and those are birds. Even though they are also 100% theropod, they are very specialized theropods, or 100% bird. There are no non-bird theropods visiting our bird feeders.

This isn't the case in the Early Cretaceous. There were non-avian theropods. There were Paraves - all theropods more closely related to birds than to oviraptorosaurs, like Velociraptor and Microraptor. There were Avialae - all theropods more closely related to modern birds (Aves) than dromaeosaurs. There are many many more categories, and then we get to Aves, our modern birds. All of these groups were running around in the Early Cretaceous, leaving footprints. How do we recognize a bird footprint as a footprint that could not have been made by anything other than a bird? It's like trying to find Cinderella (the trackmaker) using the glass slipper (the footprint), except that Cinderella died a long time ago and all we have is the skeleton of her foot to try to fit into the shoe.

So...what would the footprints from these different groups look like? How birdy does a footprint need to be in the Early Cretaceous before we call it a bird footprint? Welcome to my area of research! Since I see a lot of Early Cretaceous footprints, I'm starting to see a few track shapes that are baffling (exciting) this bird nut. Are they bird tracks that just look theropody? Are they theropod tracks that just look birdy? Are they really small plant-eating dinosaur tracks that look birdy and theropody?

NOTE: Birdy and theropody are not technical terms. I've just spent months and months writing "possessing the characteristics of bird footprints" when I really wanted to write "this feature looks birdy", so...yeah. "Birdy" is me rewarding my brain for behaving itself.

Even if there were no skeletons of small shore- and wading birds from the Early Cretaceous, small bird footprints are relatively easy to identify. In fact, the first bird footprints described from the Early Cretaceous of North America were done without any contemporaneous skeletons to support that identification. They looked birdy enough to identify as fossil bird footprints. If a footprint is small, (under 5 cm long), has widely splayed digits, and has a backwards-facing hallux (digit I), very few people are going to look at that footprint and say it's not a bird.  This is called the phenetic-based method of identifying a potential trackmaker. Basically, if it looks like a bird footprint, and walks like a bird, it's a bird. Lockley et al. (1992) provided this birdy footprint checklist:

1. It looks like a modern bird footprint,
2. Small size,
3. Slender toes,
4. Toe splay (or digit divarication) of the forward-facing toes wider between 110-120 degrees, or more,
5. Backwards facing (or posteriorly directed) hallux,
6. Slender claws, and
7. The claws on the inner and outer toes curve away from the middle toe.

There are a few more, such as track density, associated feeding traces, and associated fauna, but these have little to do with the shape and structure of a bird foot, so I won't be talking about them right now.

The other method for proposing a trackmaker for a footprint is called the synapomorphy-based method. If there is a feature in a footprint that is made by a derived character that is shared by all the members of that group, you can say the potential trackmaker came from that group. Carrano and Wilson (2001) listed the synapomorphies that have a chance of preserving as trace fossils. I refined the list further and stated the ones that were foot-specific:

1. We can say the trackmaker is a theropod if the footprint has toes with claws, and if the axis of the footprint is formed by the middle digit (mesaxonic).

2. We can say the trackmaker is Paraves if the footprint has a reduced inner toe (digit II) that lacks a claw impression.

3. We can say the trackmaker is a bird if the footprint was made on thin substrate and has a backwards-pointing hallux. This is the only synapomorphy-based feature that can be used to identify a footprint as a bird footprint in this method.

A frustratingly short list, no? Yes and no. Synapomorphies, if they impress, will provide an unambiguous "YES! This is most definitely a footprint of Awesomasaurus megarex!" A synapomorphy-based identifucation will also guard against rather, um, let's call them over-excited people, from sticking a sauropod identification on every large hole in the ground, or a tyrannosaurid identification on every large poorly preserved footprint with three toes from the latest Cretaceous Period. A major problem with the synapomorphy-based method is that most synapomorphies are NOT foot-based. Unless a Tyrannosaurus rex goes Hellraiser-wild, strips the skin and flesh off of its skull, and then face-plants into a nice clay-rich silt, most synapomorphies are going to remain unimpressed, and unpreserved, in the trace fossil record.

What do modern bird footprints tell us?
There are issues with both methods, and all of the issues are best demonstrated by looking at modern bird footprints. Birds, in their glorious diversity, come in all shapes, sizes, and habitat preferences. They are a perfect test case for both the phenetic- and synapomorphy-based methods. I looked at the four most common features that are used in the scientific literature to identify bird footprints: the backwards pointed hallux, small size, widely splayed toes, and skinny toes.

Synapomorphies Are Not Always Impressive
Let's look at the posteriorly-oriented digit I, a.k.a. the hallux. This feature is used in both the synapomorphy-based and phenetic-based methods of identifying a trackmaker. Here's an image of the foot of a bird that spends a lot of time on the ground. Festively enough, it's a turkey foot.

Wikimedia photo of turkey feet. The hallux is the lowest backwards-pointing toe. The structure higher up on the metatarsals (or "lower leg") is a spur, common in male gamebirds.

The toe hanging off the back of the foot is digit I. This is the equivalent of our big toe. If a human foot was shaped the same way as a bird's foot, our big toe would be hanging off the sole of our foot, and we'd have to walk on our tip-toes to avoid squishing it. Let that mental image sink in for a minute.

Each toe (or digit) is a series of smaller bones called phalanges. Each set of phalanges is attached to a metatarsal. Metatarsal I, or the metatarsal for the hallux, isn't a fully-developed bone in most theropods: it's short and attaches somewhere on metatarsal II, like this:

Comparison of theropod (Coelophysis, Deinonychus) and bird (Archaeopteryx, Pigeon) feet, showing where digit I (the short one) attaches to the foot. Digit I of theropods attaches much higher than the digit I for birds. Image created and used with permission by Emily Willoughby. Once you follow this link to the page with the above image, check out the rest of the site. The feathered theropods are glorious!

The big difference between birds and non-avian theropods is where the metatarsal for digit I attaches. In theropods, you can see that digit I is attached higher up on the shaft of metatarsal II. Compare that to the images of Archaeopteryx and the pigeon on the right: metatarsal I attaches low down on metatarsal II - much lower than in the non-avian theropods. With a metatarsal I (and the toe that attaches to it) attached so low on the metatarsal, it's easy to assume that the hallux would always make an impression in a bird footprint. Unfortunately (for us ichnologists) that's not the case.

First, there is a HUGE diversity in hallux length for birds that spend a great deal of time on the ground: this means gamebirds (grouse, turkeys, pheasants), shorebirds (plovers, sandpipers), and long-legged wading birds (cranes, herons, storks). Some of our small shorebirds, like plovers, have a relatively poorly developed digit I: metatarsal I doesn't really make much of an attachment mark on metatarsal II, and the toe for digit I is very short.

Distal metatarsals of the Semipalmated Plover (Charadrius semipalmatus). There really isn't an obvious attachment point for the hallux, which should be somewhere to the left of the rounded end of metatarsal II.

Plover footprints don't often have a digit I impression with their footprints, even if they walk in the best-case sediment. A fine-grained sediment (like silt or clay) can't preserve a hallux that doesn't hit the ground. If a bird in the Cretaceous has a plover-like foot, it's going to leave a footprint without a hallux (check out Paxavipes footprints here). Paxavipes can be identified as a bird footprint by the phenetic method, but since it lacks a hallux in a fine-grained sediment, it cannot be considered a bird footprint using only the synapomorphy method.

No one is going to have much trouble convincing other people that Paxavipes is a bird footprint - after all, it's teeny! But size is a really crappy way to identify a potential trackmaker (remember Carnosauria?) Many birds may be (and were) small, but birds are not exclusively small-bodied. OK, compared to T. rex, all birds, even the ostrich, are going to seem small. However, birds like ostrich, herons, cranes, storks, turkeys are not only large in the bird world, but they are similar in size to small non-avian theropods, as are their footprints. Sandhill Crane footprints range in size between 9 cm and 12 cm in length (Elbroch and Marks, 2001), and the small theropod footprints called Irenichnites are about 10 cm in length.

Second, there's a huge diversity of sediments that birds of all hallux types walk in. Not all sediments are the best at preserving all the features (see webbing versus skin impressions in my previous post here). For birds such as the Great Blue Heron, their digit I is so long and robust that it will likely impress in some fashion in many types of sediment.

One of my Great Blue Heron footprints. This heron was walking in a very water saturated, sloppy silt. Some of the details are great (like the webbing in between toes III and IV), but the hallux (I) is a little sketchy.

However, not all large wading birds have a heron or egret-like long hallux: Sandhill Cranes have a much shorter hallux than do herons and cranes. Also, their footprints don't always leave a digit I impression depending on the consistency of the ground they are walking on (Elbroch and Marks, 2001). And there's no doubting that Sandhill Cranes have a well-developed digit I - check out this fossil tarsometatarsus of a Sandhill Crane from the La Brea Tar Pits.

Sandhill Crane distal tarsometatarsus (LACM G4882, Pleistocene) from the La Brea Tar Pits, with a well-developed hallux (see attachment point circled in red), but a hallux that doesn't always show up in the footprint.

This is where assumptions in science can cause trouble. If you assume that all bird footprints have some sort of hallux impression, and if you assume that any tridactyl footprints from the Cretaceous above 10cm in length definitely cannot be bird if there is no hallux, you might be missing out on interesting paleodiversity data for early birds. The footprint evidence for large wading birds in the Early Cretaceous is growing. There is Limiavipes curriei  from western Canada (McCrea et al. 2014), a similar (yet slightly larger) footprint called Wupus agilis from Chongqing, China (Xing et al. 2014), and footprints from Dinosaur Cove, Victoria, Australia (Martin et al. 2014). All of these footprint types indicate that there was likely more than one crane or heron-sized bird wading along the Early Cretaceous shorelines.

Covering the Spread: Details on Digit Divarication

What about the wide splayed digits? Ichnologists take a measurement called digit divarication. This is the angle made by the outer toes, digits II and IV, and it's measured like this:

The arc between digits II and IV is the total divarication. Modified from Xing et al. (2014).

Birds, in general, are supposed to have a total divarication that is larger than 110 degrees, with theropod footprints having a splay that is generally below 90 degrees. This doesn't always work. Here's a small sample of data from modern bird footprints I've collected:

• Great Blue Heron: 97.7 degrees (88 - 110, N = 10)
• Canada Goose: 82.6 degrees (73 - 95, N = 15)
• Spotted Sandpiper: 106 degrees (86 - 133, N = 34)
• Solitary Sandpiper: 111 degrees (90 - 130, N = 20)

These prints each come from one individual, so this is a sample of the natural variation in toe splay that one trackmaker can exhibit. In general, the larger birds have a slightly lower digit divarication than the smaller birds. Not all bird footprints are going to have a high digit splay.

The same goes for theropod footprints: Magnoavipes was once thought to be a very large bird footprint - we're talking footprints that are over 20 cm long (Lee 1997) - because the splay of the toes was above 90 degrees. Several studies since (Lockley et al. 2001; Matsukawa et al. 2014; Xing et al. 2014) have demonstrated the likely trackmaker was a long-legged theropod, like an ornithomimid (Matsukawa et al. 2014). Just as birds can have narrow footprints, some theropod footprints can have widely spread toes. That's natural variation. As for size, digit splay can't be the only criterion used to say "Aha! Bird footprint!"

The Skinny on Digit Thickness

Remember before when I said that size is a crummy feature to use when identifying a trackmaker? Size and the thickness of the toes of a trackmaker are, in general, closely related. Check out how thick the toes are on this emu (a large bird) footprint).

Wikimedia image of an emu footprint. There's also skin impressions!

Small birds can also have relatively thick digits.

Figure from my thesis comparing digit thickness in Cretaceous bird footprints. A, Tatarornipes (Lockley et al. 2012); B, Koreanaornis dodsoni (Xing et al., 2011); C, Morguornipes (Xing et al. 2011); D, Aquatilavipes swiboldae (Currie, 1981). There is a great deal of variation in the thickness of the toes.

Some of this variation in toe thickness may be due to soft-tissues on the feet of the trackmakers. Some of this variation might be related to the water content in the ground the birds were walking on, and how those footprints preserved. Wet, gloopy sediments will collapse in on themselves after the toes leave, making a footprint with unnaturally skinny toes. Again, using just one feature, like skinny toes, is not good enough to identify a footprint as having been made by a bird. Observing shorebirds in their natural habitats is a great way to become familiar with how one bird can leave a variety of very different looking footprints.

How Do We Identify Large Bird Footprints (Or Small Theropod Footprints) Without Stepping In It?

The only way to make sure we make the most accurate identification we can is by using ALL the information present. This means that we can't just rely on one measurement or observation to make the identification of an avian trackmaker. We also can't ignore all of the other information present in favor of one measurement or observation - that's called cherry-picking, and that's a big data interpretation no-no. Birders have a term, gestalt, that roughly translates to "the whole being greater than the sum of its parts" (Sibley 2002). While this may sound quite unscientific, it's a good reminder to those of us looking at bird footprints that we need to look at all of the variables at play when making our identifications. In a way, gestalt tracking combines both the phenetic and the synapomorphy methods, but also takes into account all of the reasons why those key features might not be there, or might look different than expected. Gestalt tracking can make us a little more comfortable with the ambiguities inherent in ichnology.

We also have to make sure that we make use of the living laboratories that we have outside of our museums and computer labs. This is why I spend some time every summer slogging through muck and mire to watch birds make footprints in their natural habitats - I like to see all the variables that go into the bird taking a step to the final shape of the footprint. This type of fieldwork is crucial to understanding how birds leave the traces that they do, and will give us a better understanding of how fossil birds did what they did.

References


Buckley, L. G., R. T. McCrea, and M. G. Lockley. 2015 . Birding by foot: a critical look at the synapomorphy- and phenetic-based approaches to trackmaker identification of enigmatic tridactyl Mesozoic traces. Ichnos 22(3-4):192-207

Carrano, M.T., and J. A. Wilson. 2001. Taxon distributions and the tetrapod track record. Paleobiology 27(3):564–582.

Currie, P. J. 1981. Bird footprints from the Gething Formation (Aptian, Lower Cretaceous) of northeastern British Columbia. Journal of Vertebrate Paleontology 1(3–4):257–264.

Elbroch, M., and E. Marks. 2001. Bird tracks and signs: a guide to North American species. Stackpole Books, Mechanicsburg, Pennsylvania, 456 pp.

Lee, Y.-N. 1997. Bird and dinosaur footprints in the Woodbine Formation (Cenomanian), Texas. Cretaceous Research 18:849–864.

Lockley, M. G., J. Li, M. Matsukawa, and R. Li. 2012. A new avian ichnotaxon from the Cretaceous of Nei Mongol, China. Cretaceous Research 34:84–93.

Lockley, M. G., J. L. Wright, and M. Matsukawa 2001. A new look at Magnoavipes and so-called “big bird” tracks from Dinosaur Ridge (Cretaceous, Colorado). Mountain Geologist 38:137–146.

Lockley, M. G., S.-Y. Yang, M. Matsukawa, F. Fleming, and S.-K. Lim. 1992. The track record of Mesozoic birds: evidence and implications. Philosophical Transactions of the Royal Society B 336:113–134.

Martin, A. J., P. Vickers-Rich, T. H. Rich, and M. Hall. 2014. Oldest known avian footprints from Australia: Eumeralla Formation (Albian), Dinosaur Cove, Victoria. Palaeontology 57(1):7-19.

Matsukawa, M., K. Hayashi, K. Korai, C. Peiji, Z. Haichun, and M. G. Lockley. 2014. First report of the ichnogenus Magnoavipes from China: new discovery from Lower Cretaceous inter-mountain basin of Shangzhou, Shaanxi Province, central China. Cretaceous Research 47:131–139.

McCrea, R.T., L. G. Buckley, A. G. Plint, P. J. Currie, J. W. Haggart, C. W. Helm, and S. G. Pemberton. 2014. A review of vertebrate track-bearing formations from the Mesozoic and earliest Cenozoic of western Canada with a description of a new theropod ichnospecies and reassignment of an avian ichnogenus. New Mexico Museum of Natural History and Science Bulletin 62:5–93.

McCrea, R. T., L. G. Buckley, A. G. Plint, M. G. Lockley, N. A. Matthews, T. A. Noble, L. Xing, and J. R. Krawetz. 2015. Vertebrate ichnites from the Boulder Creek Formation (Lower Cretaceous: middle to ?upper Albian) of northeastern British Columbia, with a description of a new avian ichnotaxon, Paxavipes babcockensis, ichnogen. et, isp. nov. Cretaceous Research 55:1–18.

Sibley, D. A. 2008 Sibley's Birding Basics. Knopf Doubleday Publishing Group, 168p.

Xing, L., L. G. Buckley, R. T. McCrea, M. G. Lockley, J. Zhang, L. Piñuela, H. Klein, and F. Wang. 2015. Reanalysis of Wupus agilis (Early Cretaceous) of Chongqing, China as a large avian trace: differentiating between large bird and small theropod tracks. PLoS ONE 10(5): e0124039. doi:10.1371/journal.pone.0124039

Xing, L.-D., J. D. Harris, C. K. Jia, Z. J. Luo, S. N. Wang, and J. F. An. 2011. Early Cretaceous Bird-dominated and Dinosaur Footprint Assemblages from the Northwestern Margin of the Junggar Basin, Xinjiang, China. Palaeoworld 20:308–321.

Scientific Humor and the Woofen Poof

[UPDATE: Not to be confused with the Yale a cappella group, the Whiffenpoofs.]

Have you ever come across something in the scientific literature so hilariously bizarre that you have no idea 1) how or why it came into being in the first place, and 2) why you are not hearing about it until now? Rich recently found and purchased a paper of just such hilarity, and it tickled my humerus so much that I had to share.

Please allow me to introduce (or, if you are already acquainted with the plucky fellow, reintroduce) the bird Eoörnis pterovelox gobiensis, also known as the Woofen-Poof.

Picture of a Woofen-Poof resting on a rocky outcrop in the Gobi Desert. From the 1928 Fotheringham monograph.

I can hear you loudly exclaiming "Oh come on! There is no way that's a real bird! There's no way that's an actual paper!" You would be both correct and incorrect: no valid taxon carries the name, but the papers do exist. Take a moment to wipe the snorted beverage off of your screen, and I'll present a summary and commentary of the Woofen-Poof, with tongue firmly in cheek. Don't worry - I'll make sure to distinguish fact from fiction in my summary.

FACT: If you hear me giggling each time you read Woofen-Poof, it's because I am.

The Woofen-Poof

FACT: The Woofen-Poof first made its scientific appearance in 1930, in Volume 5, Issue 1 of the Quarterly Review of Biology under "New Biological Books". Authors weren't stated, but it was presumably done by Lester B. Sharp and Cuthbert Fraser (see below: The People). Presented was a review of an obscure monograph on Eoörnis pterovelox gobiensis as written by Augustus C. Fotheringham. It was stated in the 1930 review that "[c]opies may be obtained from Dr. Lester W. Sharp, N. Y. State College of Agriculture, Cornell Univ., Ithaca, N. Y.)", and that the Fotheringham article is a first edition of 500 copies. No date of publication was given in the review, but the monograph made available by Sharp has the publication date of 1928.

Cover of the Woofen-Poof monograph.

In this classic work, Eoörnis was documented by an expedition to the Gobi desert led by Brigadier-General Sir Cecil Wemyss-Cholmondeley, for which A. C. Fotheringham was scientific director. The following are some select photos from the field as presented in the monograph, and commentary summarized from the monograph and the 1930 review. These are not all of the images from this fantastic monograph, but they represent my favorites.

Scanned from the 1928 monograph.

First, the Woofen-Poof is figured (left) perching on a branch of Ginko biloba. Right is featured the nest of the Woofen-Poof. Note the majestic metallic sheen on the...er...um...plumage(?) of the Woofen-Poof, provided by the large oily glands the Woofen-Poof uses to groom itself. Woofen-Poofs are small birds, approximately 17 cm long from beak tip to tail tip, and have a wingspan of only 6 cm. It is a brown bird, except during mating season, when the female develops black speckles on the breast, body and tail feathers. The wings are in constant use despite their small size, and lack the proper joints to be folded when not in use.

The nest (right) is figured in the monograph, and describes the Woofen-Poof as a ground nesting bird that conceals its eggs among other similarly-sized spheroids. The nesting and breeding strategy are startling, as summarized in the 1930 review:

Quote from the 1930 review. Dr. Sharp's research focus in cytology is evident in several places in the Woofen-Poof monograph: there is an entire section detailing cytological studies of Eoornis.Sorry, male Woofen-Poofs: fertilization isn't required when you reproduce via parthenogenesis.

Ichnology also plays a role in interpreting the nesting biology of the Woofen-Poof. The Woofen-Poof had to stealthily hide its eggs among decoys because, according to the reptile Lepidosaurus obscurus (below), Woofen-Poof eggs are delicious.

FACT: Figure 18 almost killed me. I was staring, staring, staring...and then it came to me: the entire white object is the "fossil"! I believe someone (looking at you, Sharp and Fraser!) was having a little laugh at how fossils are interpreted. They may have also been poking fun at many of the pseudofossils that scientists are asked to identify. I've seen my fair share of "skulls" that are really just round rocks with a couple of "eye sockets". Figure 18 is a textbook case of how people see fossils using pareidolia.

As a completely humorous aside, I must respectfully offer an alternative hypothesis to that of the Lepidosaurus nest-robbing interpretation. The skeletal reconstructions of the Woofen-Poof do not show the fusion one would expect to see in the legs and ankles of a bird that never flexes them. It is possible that when the Wemyss-Cholmondeley Expedition encountered the Woofen-Poofs in the wild, that the hopping they observed was a behavioral reaction to intruders, much like the Killdeer injury display. All published images of Woofen-Poofs show a flat foot posture - they appear to retain this foot posture even in flight (see figures 23 and 24 below). If we look at the skeleton of the Woofen-Poof, shown in figure 20 of the monograph (below), the foot structure, toe proportions, and toe orientation are a close fit to the footprints shown around the Woofen-Poof nest.

Woofen-Poof skeleton. How this bird was supposed to hop in this pose without bill-planting into the sand is a mystery. 1928 monograph.

Real Ichnology: While Fotheringham interprets these tracks to be from a quadrupedal animal, he does not present information to support this idea. There is little difference between purported front limb prints and hind limb prints. Quadrupedal animals generally have a size and shape difference between the hand and the foot, even if it's a small difference. All of the prints around the Woofen-Poof nest are uniform in size and shape. Check out the spacing of the footprints. Birds have a short step length (called pace in ichnology) compared to the length of their footprints. [End real ichnology]

My hypothesis is that these are footprints of the Woofen-Poof, made as the nesting Poof walked up to the nest. Alternatively, Woofen-Poofs may have been brood parasites, with one Woofen-Poof laying her eggs in the nest of another unsuspecting nesting Woofen-Poof. This would give the parasitic Woofen-Poof all of the benefits of having reproduced, with none of the energy drain of raising the little baby Poofs. Keep this "hypothesis" in mind for the end of this post - we have news (teehee)!

While Woofen-Poofs (Woofen-Pi?) may look stoic and immobile, they are described as rapid and energetic fliers (they would have to be, with feet and legs like that). The 1930 review reports speeds of up to 600 km per hour! Figures 23 and 24 from the monograph demonstrate that photography of the Woofen-Poof was so difficult the expedition leader had to invent a new camera shutter.

Figures 23 and 24, from the 1928 monograph.

Photographing the Woofen-Poof is a perilous exercise. The expedition crew were often assaulted by agitated Woofen-Poofs, which would fly at them at full speed and attempt to impale the crew on their Woofen-Poofy beaks.

DUCK! I mean, POOF! An angry Woofen-Poof, from the 1928 monograph.

The Woofen-Poof has apparently existed at least since the Mesozoic, as proffered by fossil evidence of its food, as seen in figures 14 and 15 of the monograph.

FACT: I can already hear paleontologists chuckling at the caption for Figure 15 (right). The worms, Palaeolumbricus dubius, are really ammonites. The "worm" is also referred to in the 1930 review as the "now extinct Cro Magnon worm".

The Woofen-Poof is reported to appear as art on the walls of Cro Magnon cave, in an amulet of King Tutankhamen, and mentioned by both the Roman historian Eutropius and Marco Polo. No worries, archaeologists: there is something for everyone in the Woofen-Poof literature!

Fotheringham spends a great deal of time discussing the fascinating evolutionary history of the Woofen-Poof. The Woofen-Poof, being unique as all heck, is the sole representative of its genus (Eoornis) and its class, the Pterovelocidae.

FACT: Remember the taxonomic ranks from high school? "-idae" endings are for family-level groupings, while "-ia" endings are for class- level groupings. Fotheringham really should have called this group the family Pterovelocidae, or the class Pterovelocia.

Fotheringham discuss several anatomy and behavior traits that link the Woofen-Poof to Australia. The small wings and historical diet of "Cro Magnon worms" of the Woofen-Poof suggest anatomy and behavioral links to the kiwi. The monograph also states that the Woofen-Poof shares a beak pouch with the pelican. Since all occur(ed) in Australia, Australia is the logical evolutionary birth-place of the Woofen-Poof.

Fotheringham completely rejects the evolution scenario presented by his colleague, Adolf Weilder-Goesser. The scenario is this: 1. Woofen-Poofs have retractable eye stalks, 2. Snails and other molluscs have retractable eye stalks, 3. Woofen-Poofs are birds. Naturally that brings us to 4. Birds and molluscs have an evolutionary relationship. Fotheringham rejects this idea based on the different speeds at which these animals travel: snails are slow, while Woofen-Poofs are fast.

Now we reach the point where Fotheringham discusses why the Woofen-Poof has proven to be the most significant discovery in paleontology history. When first discovered, Pterodactylus and Archaeopteryx were cited to be "missing links" between reptiles and birds. These two fossils were important fossil missing links, but what if a living missing link could be discovered? TA-DA! The Woofen-Poof shares many features with pterosaurs, particularly Pterodactylus avioancestricus, this it firmly cements the bird + Woofen-poof + pterosaur link.

Pterodactylus avioancestricus. Figure 34 from the 1928 monograph. According to the monograph, the paper describing this great new pterosaur was in progress in 1928. I guess we're still waiting.

What is the future of the Woofen-Poof? Fotheringham details bleak information on the unique neurological condition of Woofen-Poofs: a priori reasoning (reasoning that stems from theoretical knowledge) and a posteriori reasoning (reasoning that stems from observations and experiences) are perfectly balanced. In other words, Woofen-Poofs can easily be rendered indecisive, even to their own detriment. In what had to be a heart-wrenching experiment to perform, a Woofen-Poof was placed an equal distance between two piles of food. Its neurological condition rendered the poor Woofen-Poof unable to choose one pile of food over the other, resulting in its eventual death by starvation seven days later. Even if the Woofen-Poof can overcome its quirky indecisiveness, it may die between the ages of seven and 35 years due to deterioration of the lumbar ganglion. Poor, poor Woofen-Poof.

An unfortunate Woofen-Poof, rendered indecisive (and dead) after seven days between two piles of food. I challenge you not to be moved to tears by this pitiful scene. Figures 29 from the 1928 monograph.

Who are these interesting cast of characters?

1. The People

Augustus C. Fotheringham

A Google search of that name comes up with all things Woofen-Poof. It also comes up with information on the botanist Lester W. Sharp, pioneer in cytogenetics. Given that the images show the Woofen-Poof is quite obviously a metallic model (pick your favorite - they're all ridiculous), there can be little doubt that Sharp and Fraser knew they were not fooling anyone in the scientific community: this was a science joke, and an obvious one at that. That didn't stop Sharp from having what looks like a tremendous amount of fun with the Woofen-Poof. The monograph contains many references to the cytogenetics of the Poof, and has a dry chortle at not only cytogenetics, but archaeology, paleontology, biology, psychology, and several other science specializations. That didn't stop people from using the Woofen-Poof as serious science (see below: The Hoaxed).

Brigadier-General Sir Cecil Wemyss-Cholmondeley, and the Wemyss-Cholmondeley Expedition

I don't think it will come as a surprise to learn that there was no person who bore that exact moniker. The name appears to contain parts of names of several real British generals and brigadiers, notably General Sir Henry Colville Barclay Wemyss (1891–1959), and Major-General Allan Cholmondeley Arnold (1893–1962). Alas, this means there is no Wemyss-Cholmondeley camera shutter, and no upcoming monograph on the fictional Pterodactylus aviancestricus.

2. The Hoaxed

Yes, someone took the Woofen-Poof seriously. A cringe-worthy article in Eugenics Review by Anthony Ludovici from 1933 cited examples of incest or consanguineous breeding in nature to support the "purification of [human] stock". One of these examples is our poor Woofen-Poof. I had hoped the article was satire, but that hope was dashed when I read the Wikipedia page for the author. Read the titles of his works ye mighty, and despair. I'll leave this here for anyone who wants to use it.

Eternal gratitude to Mammals Suck...Milk! for posting this gif. My quality of life has improved tremendously since.

Clearly the Woofen-Poof had made the academic rounds by 1933. I'm assuming that Ludovici didn't bother to contact Sharp to obtain a copy of the monograph, or else he would have realized the Woofen-Poof was not the best example to lend credence to his work. The alternative is that even if he did know, he may not have cared. Cherry-picking data, poorly researching data, and misrepresenting data to "prove" a pseudoscientific idea (and sometimes a scientific idea) isn't new. It would be simple to just laugh at the old-time racist (and elitist, and misogynist, and ableist...he was committed to being an unsavory character), but it's difficult to laugh when these beliefs are alive and squirming today.

Our New "Discovery" (a.k.a. Having more fun with the Woofen-Poof)

There have been no reports of the Woofen-Poof since its announcement in 1930. At the time of its description, the Woofen-Poof was thought to be restricted to the Gobi Desert. Fortheringham suspected the Woofen-Poof had a larger range than described in the 1928 monograph, and proposed Australia as the next logical place to search for this elusive bird.  However, in a groundbreaking discovery of the utmost scientific importance, we report the possible presence of the Woofen-Poof in northeast British Columbia. Allow me to present my evidence, Woofen-Poof style.

Yup. Totally 100% legit Woofen-Poof tracks in BC. Hey, why are you laughing?

This picture was taken today. There are three tracks in a single trackway of a small, three-toed trackmaker. These tracks most closely match bird footprints, but they do not match any known bird from the Peace Region. They are remarkably similar in shape to the prints that I interpret at Woofen-Poof prints. These prints do not display the reported hopping behavior, as these prints were made by a bird that was not under stress. Also, ammonites (or Cro Magnon worms of Fortheringham, 1928) the ancestral food of the Woofen-Poof, were present in BC during the Mesozoic. While this trackway does not 100% confirm the presence of a northern North American population of the elusive Woofen-Poof, we'll be keeping our eyes out for more evidence. Stay tuned!

Now to be serious.

Why am I so amused by this paper? It shows that scientists have a sense of humor, and have had a sense of humor for a long time. Science usually presents itself as serious business, and we spend a lot of time writing serious scientific papers. Our research has to be professional - we have to get the facts out so they are clear, because other people make real decisions that impact real people based on these studies. There's not a lot of room in these papers for puns, groaners, and Muppet Show antics. Sometimes I think non-scientists (and even a few scientists) forget that we're also human beings, and we're human beings who appreciate humor.

Social media is a great place to check out where scientists regularly poke fun at themselves and their craft. Hashtags such as #scienceamoviequote come up regularly. #scienceamoviequote quote falls under the category of the inside joke: scientists are making fun of their terminology, statistical tests, paper writing (and rewriting, and rewriting...), grant writing, committee posts, exam grading, and all of the other trials of academic life. These are jokes by scientists, for scientists. Since we all have had to deal with these issues, we poke fun at them with our colleagues to break down that feeling of isolation and frustration that inevitably results from working in a demanding field. The Woofen-Poof is an elaborate inside joke. A non-scientist has a very good chance of either not understanding that it is a joke, and/or taking it as a serious piece of scientific literature.

We also find the humor in events which have a broad appeal. Collecting our data can put in silly and embarrassing situations, as demonstrated by #fieldworkfail. Everyone can relate to getting a vehicle stuck, losing that important bit of equipment, or have an animal cause mischief. We also realize that some of the subjects we study may sound giggle-worthy (like genitals). Laugh away (we do), but mating and genitals are just as important to document as any other parts of an organism's behavior and anatomy, as we saw in #junkoff.

We also encounter those who abuse joking in science. There are still too many people in every discipline who express their biases towards junior and/or underrepresented groups, and then try to excuse their words as "just a joke" when they are later told they were being unprofessional (see Dr. Kate Clancy's "Jokes that Don't Work" and Hilda Bastian's "Just Joking?"). An easy rule: if the "joke" turns an underrepresented group and the issues they face into a punchline, it's not a joke. Treat people the way you would want to be treated if you were in their position.

Humor is a great outreach tool when used properly. A non-scientist may not completely understand why I need to (or would want to) spend a lot of time trekking through the wilderness looking for bird footprints, but they can appreciate how funny it is if I sink up to my waist in muck, or have my backpack attacked by my study subject.

This juvenile White-tailed Ptarmigan, a tiny alpine game bird, cheekily strutted up to my back pack and hissed at it. Photo by L. G. Buckley.

Humor can be a bridge connecting the general public with the scientific world. I think the people who are the most intimidated by the idea of science are those who don't know (and may not care) exactly what it takes to do the science. It's easy to reject something you can't feel any connection to. Science isn't a scary secret conspiracy, and the people who do science don't sit up nights thinking of ways to pull one over on the unsuspecting public. We do work, and that work is finding out as much about the natural world as we can so that we can better understand our place in it. That work, like any other work, has moments of joy and frustration, satisfaction and discouragement, hazard and humor. Scientists experience all of these moments as people, not papers. The serious paper is only one small part of the entire experience of conducting a scientific study. The more we talk about how we get to the final results, the less scary the process seems.

Has anyone else seen the elusive Woofen Poof?


References

Brief notices. 1930. New biological books. Quarterly Review of Biology 5(1):98-131. Check out pages 112-113 of this article.

A. C. Fotheringham. 1928. Eoörnis pterovelox gobiensis. The Buighleigh Press, London, 1-34.

New Phase, New Title!

Oh My Frog, I made it.

By "it", I mean I passed my doctoral defense. I have some revisions to do, but by the end of this term I'll be done. DONE.

Rich made a wonderfully apt comparison between Alien 3 and the thesis, where Ripley says to the xenomorph "You've been in my life so long, I can't remember anything else."

That's what this thesis feels like. I've carried that "You should be working on your thesis" mantra in the back (and the foreground) of my thinking for so long, I don't know how else to think. I can transfer that thinking to all of the post-doctorate projects that I have chomping and stamping behind the gates, but none of those projects will come with that big hurdle to clear.

With that in mind, I want to change my blog title to reflect more of the things that I actually do, which is muck around in the muck with birds, fossil bird tracks, science and museum life, and other things that impact the life of this particular paleontologist.

The "Shaman of the Atheistic Sciences" title was me mocking what was meant as an insult. A person with whom our institution had a friendly field work relationship did a rather confusing (to us, anyway) 180 degree shift and all of a sudden started accusing us of stealing all of BC's fossils to do...well, that part was never clear. There was some conspiracy-like elements to the rather lengthy rant. For all I know, we were piling BC's fossils in the center of collections and sleeping on them, Smaug-style. Regardless of the perceived reasons for our "fossil hoarding", the finishing line of the last direct communication we had from this person was that they would henceforth be turning to the Bible for all of their information on natural history and not the "shamans of the atheistic sciences".

Well then. In the words of the well-known GIF, that escalated quickly. This was no doubt supposed to be a dig at us, at other cultures, and those working to preserve our planet's natural history. If I had access to GIFs back when the comment was made, the above one would have been the perfect response.

I'm here for all the cool birds, fossil and modern bird tracks, fossil heritage conservation, and all the great paleontology I get to be involved in, and I want my blog title to reflect that.

So...

Hear Ye, Hear Ye! From this day forward, this teeny corner of the Internet shall be known as...

STRANGE WOMAN STANDING IN MUD, LOOKING AT BIRDS.

Cheers!

I'm Lichen These Tracks!

(I'll see myself out. Oh, wait: this joke needs context.)

Our field season in northeast British Columbia is comparatively short. We usually confine the bulk of our field activities to July and August, with June and September-October reserved for shorter field excursions. The weather is twitchy in September: one day it may read 20C on the thermometer, and the next day there may be a dusting of snow on the lawn.  I am admittedly not a cold-weather person: when we recovered a slab containing an isolated tyrannosaurid track in late December, I received small patches of frost bite on three of my toes while wearing heavy boots and wool socks (to be fair, those boots were old). Any field work we can do after the end of August without turning into ichnocicles is bonus field work.

Yesterday we (me, Rich, and our field assistant Tammy and volunteer Linda) did a day-trip into a newly explored canyon with Early Cretaceous outcrop. We're not exactly sure where we are in terms of the rock layers (also known as the stratigraphic section) as all the mountain building activity has crumpled and folded the layers like Wile E. Coyote running head-first into a canyon wall. From the pictures brought back by our volunteer field crew, we could see that there were some interestingly small tracks on the near-vertical rock face. They were at standing height, which was a welcome surprise for us, since most of our vertical track exposures require ropes to access. That was the good news. The less than good news was that the tracks were coated with a layer of our old crusty friend, the Lichen.

Not for the last time.

Lichen, while a fascinating symbiotic organism, is a bit of a pain in the butt when it comes to ichnology. Lichen has its own topography, and it can obscure fine details on track surfaces. Lichen is also a pain to remove. Mechanical scraping is out of the question for tracks as it would scrape off all the cool details (skin impressions, behavioral traces), so we have our chemical method of removing lichen.

I talked about this method a bit in the post about Paxavipes babcockensis, the third Cretaceous bird footprint to be named from Canada. Here I'll show how to employ the techniques of Buckley and McCrea (2009) in field settings.

The morning started out foggy and frosty, with the thermometer reading 1C. Welcome to fieldwork in the Peace Region in September! The weather at this time of year is twitchy, so I layered up in long underwear. We knew it would warm up during the day, but this site is in the bottom of a steep-walled creek canyon and receives little sun, so no matter how warm it was going to be outside of the canyon, inside the canyon it would remain cool and damp.

I packed down the bleach treatment supplies. We needed:

• A spray bottle of bleach solution, diluted to about 25% strength,
• Several pre-cut pads of cotton cheesecloth,
• Plastic cling wrap,
• Black Gorilla Tape - yes, this stuff is amazeballs for sticking to cold rock surfaces,
• Gloves, eye protection
• A stiff-ish brush, but NOT a wire brush. A whisk broom worked well, as well as a sturdy synthetic sponge,
• Garbage receptacle (a 5 gal. bucket for carrying all the equipment served as this).

When I say steep-walled canyon, I mean STEEP. The slope was nothing more than large loose boulders held in place by moss. Moss makes for a cushy soft hike, but it is not considered a reliable industrial adhesive, so we had to be very careful. Every step down had to be tested before trusting my weight on the seemingly secure surface. Field Work Tip: don't EVER be in a rush to get anywhere. That's how accidents happen. Fortunately we made it to the bottom of the canyon incident-free.

Unfortunately I can't show any images of the traces at this moment. They are going to be part of a paper that I'm working on with several coauthors, and many journals have strict rules on talking about what you're going to publish before you publish it. Hopefully I'll be able to talk about it until your eyes bleed. Soon.

First, I gave the track surface to be treated a good brushing with the stiff brush. This was to remove any extra clinging dirt, and to rough up the lichen surface so that the bleach treatment could soak in.

There could be all manner of interesting traces under this lichen and we wouldn't see them!

Next, we soaked the cheesecloth pads in the bleach solution (wearing our safety gear!) and pressed them on to the surface.

Field technician Tammy adding bleach to cheesecloth.

Volunteer Linda telling the cheesecloth to stick, darnit!

After the soaked cheesecloth was applied, we covered the entire works with plastic cling film.

A picture of my test patch. I always do a test patch along with the actual treatment. This patch is the one I check every half hour to see if the treatment has worked, rather than disturbing the actual treatment.

You know how cling film only sticks to things you don't want it to stick to (itself) and refuses to stick to anything else? That's where the Gorilla Tape comes in. All of the edges and seams of the cling film were firmly taped to the wall. This keeps the bleach solution from drying out before it has a chance to work, and keeps the soaked pads firmly pressed against the lichen. The tape and plastic also keep the treatment from oozing down the slope.

Taped. Time to play the waiting game.

Now we had nothing to do but wait. We had applied the treatment by 12:30pm, and I checked it every half hour. Once the lichen was soft enough to remove with a firm scrubbing with the sponge (2:15pm) we gave the surface a vigorous scrubbing and washing. Once the surface dried, Rich took 3D photogrammetry images, and then we did a latex peel of the surface.

We always do a physical replica to accompany the digital replica for important, novel, and published specimens. Digital replicas are great for sharing, and for taking large-scale tracksites back to the lab on your hard drive, but a digital replica will only be as good as the technology at the time it is created. Physical replicas (when done correctly) are exact replicas, and won't be lost to the Blue Screen O' Death or a hard drive failure. Collections managers are paid to be paranoid.

We had limited daylight, so we applied a nice thick coat of museum-grade latex (sweet or low-ammonia latex) to the surface. Don't let its appearance fool you: it may look like cream cheese frosting, but it smells like cat urine.

Who wants to lick the spoon? No?

Now we are waiting for the latex to cure. Latex takes a long time to cure in cool damp conditions. Recover it too quickly and it will still be a goopy mess. Recover it too late and it will freeze and fall apart. Silicone would face the same issues: it doesn't cure well (or at all) in the cold, and the cure is inhibited if there is a hint of sulfur in the rocks (which there is).

In the end, we'll have a great additional specimen to the paper, a nice new replica to curate in the fossil archives, and another bonus fieldwork day accomplished. Not bad for September!

Strange Woman.

Buckley LG, McCrea RT. 2009. The sodium hypochlorite solution for the removal of lichen from vertebrate track surfaces. Ichnos 16(3):230-234.

Fieldwork Flail -The Ups and Downs of Being Out and About

Hello, Dear Readers!

Well, the thesis is off to the committee (eep!), so now I get to digitally dust off the blog and leave the academic hermitage that is writing thesis chapters! I've been figuratively chained to the office for most of the summer. While this was a self-imposed office banishment, having to stay indoors and write during the summer when every fiber of my being was screaming to be outdoors doing fieldwork wore on me. Needless to say, once the writing was done, I jumped at the opportunity to visit one of my favorite neoichnology sites before all the shorebirds abandoned us to the cold weather (thanks, birds). The site is a couple of hours drive from the museum and great for (long) day trip fieldwork.

What follows is a mixed bag of success and frustration: in short, it's the typical field story. 

I arranged with our summer field tech, Linda, to pick her up at 6am. I went to bed early, as I'd be up before the sun to put the finishing touches on my neoichnology field gear. Thanks to some horrid reaction to something I ate, I did not get to sleep until 2am. As I finally drifted off to sleep I thought "Oh, this trip is starting out well..."

The alarm blares off at 5am. I will be honest with you: I am not a morning person, even when I've had a decent night's sleep. "Good" is not paired with "morning" in my vocabulary. Our museum staff (morning people, the whole lot of them) take great delight in being all chipper around me when I first enter the building. The walking dead have more life in them than I do on waking. Several cups of tea infused me with what passes as life, I picked up Linda, we loaded the last of the gear into the field truck, and left town for a pleasantly uneventful drive to the site.

Oh, sorry. I slipped into telling fiction. Back to reality.

We were driving down the highway, which is pleasantly empty at this time of the morning. This means that I'm not ticking off the drivers who want to do 100-120km/hr by driving the speed limit (90km/hr). Given the driving habits of the region and the fact that we are smack dab in the middle of the BC wilderness, there are a lot of black tire marks on the highway. I didn't think anything of that new black mark on the road...until I was close enough to see that it had thickness. I slowed and swerved around whatever it was...

BANG!

My foot left the gas immediately. We slowed to a crawl. This let me know that a) my tire(s) were still attached to the truck, and b) the axles (if damaged) would last long enough to get us to a safe shoulder. We crept along the road until we found a turn-off to a gravel road, engaged the hazards, and stepped out to survey the damage.

The flattest of all tires.

Important Field Tip #1: Know how to change the tires on your field vehicle. Don't just assume that you know how to change a tire - actually practice on your field vehicle before you set off on your adventures. Everyone on your field crew needs to practice being the lead on changing a tire. Even though we were right on the highway, we had no cell service and the satellite phone was being twitchy, so there would be no calling BCAA.

Fortunately for me and Linda, while we had not been the leads on changing a tire, we knew enough from several assists how to do it. The most troublesome part of the process was lowering the bloody spare from under the vehicle because we couldn't find the thrice-damned attachment for the jack that fits into the decent mechanism. Which leads me to...

Important Field Tip #2: Keep all of your jack attachments in one area, even if they are small. It took longer than it should have to locate the proper attachment, which was helpfully located in the glove compartment. Once located, we were off to the races, so to speak. During the process we also encountered...

Important Field Tip #3: People are jerks. Don't trust that they will bother to stop, slow down, or even move their vehicle as they roar past you at 110km/hr on a relatively narrow highway. Out of the seven vehicles that drove past, not one even slowed down. This was all well and good - we didn't need help (and we didn't want the hassle of trying to tell someone that the damsels in distress actually could change a tire all by our little selves), but the gravel and dust being whipped at us from speeding trucks got old.

The tire change went smoothly. Once the tire was off...

we could see the extent of the damage. Whatever the tire had hit, it went right through. There would be no patching this tire. That tire wasn't just damaged: it was cancelled.

Linda shows us the extent of the damage.

That was Adventure #1. We decided that we deserved to stop at Tim Horton's before continuing on to the site. We also made a note of our location, because on the way back we planned to find the wretched thing in the road that thrashed the tire.

We made it to the parking area of the field site without any incident. Accessing the neoichnology site requires crossing a river. Usually the river is gentle and shallow enough at this location to cross without too much difficulty. However, recent rains had given the river a bit of vigor and depth. Each of us had a cumbersome load to pack across the river (plaster, mixing buckets, cameras, personal gear), and the local river bed flora add a nice element of slime to the bouldery river bed. Crossing would prove to be tricky.

We found a spot that looked promising, and started across. A combination of bulky gear, slimy boulders, and a slight misstep sent me flailing into the river.

SPLASH!

All I remember going in was thinking "S**t, the camera!" and holding that aloft with my right hand while my left hand let go of the bucket (which Linda retrieved before it floated off on its own adventure) and broke my fall. This area was deep enough that I didn't break my fall before going almost completely under the water - I think the top of my head was still dry - but the palm of my left hand took the full force of my fall as it hit boulders and gravel. Needless to say, there was a little bit of damage.

It's only a flesh wound...I hope.

I carry a first aid kit with me, but there was very little I could do at this point that couldn't wait until I reached civilization. Sure, I could have dug around in my hand to remove bits of embedded gravel, but nice cushiony blisters formed around the impact sites, so I knew where the offending material was located. What worried me more was the sharp ache deep in my first metacarpal - did I break or crack it? I could still move it, albeit with some discomfort, so I figured we had come too far to give up on the chance of shorebird traces.

We finally crossed the river, and I changed into more-or-less dry clothes. We had arrived!

This area is dominated by Canada Goose tracks, and the fine-grained sediment captured their trampling nicely.

Canada Goose trample surface.

With the Canada Goose tracks were smaller anseriform (duck) footprints: they have a different overall shape than Canada Goose tracks, so we knew they weren't young geese.

Duck, duck, (not) goose. Do you see the inward curving outer toes?

Did you see the webbing? Webbing is a useful feature when it preserves, but webbing is inconsistently preserved in bird tracks. If the sediment consistency is just right (firm yet damp, like a firm wet beach sand), webbing may not impress. A more reliable feature is the curvature of the lateral toes: members of the duck group (Anseriformes) with palmate webbing (a completely webbed three-toed foot) have digits II and IV (the outer two toes) that curve towards the middle digit (digit III). Sandpipers with semipalmate webbing (webbing that attaches only partly down the length of the toes) do not have inward curving side toes.

Part of neoichnology is hanging out in an area long enough to see the local wildlife. Ideally, you want to see the animal in question make the footprints. If that isn't an option, you need to know who is frequenting the area. If the tracks you are looking at are fresh, there's a better chance that the trackmakers you see are the owners of those footprints. These tracks were relatively fresh, so I knew that there was a good chance the trackmaker was either nearby or would revisit the site. All we had to do was wait.

While we were waiting, we checked out the track surface for more examples of the same type of footprint preserved in different ways. Here is a great example of how there is not one preservational scenario that will preserve all features all the time.

The webbing on these Canada Goose prints is very poorly preserved, but the hallux (digit I) on the left footprint is gorgeous! Digit I is another one of those birdy features that is inconsistently preserved, yet so many rely on the presence of the hallux impression as THE feature for saying with 100% certainty "Yes! We have a bird print!" I have a paper in press that discusses how the fossil and neoichnology data shows it's rarely that simple. Stay tuned!

We also found great samples of skin impressions for Canada Goose footprints. This print doesn't look like much at first glance - no webbing, no hallux, no "heel" pad (which isn't really a heel, but a fleshy pad where the toes and the end of the metatarsals connect)...

...but on closer inspection, it has great skin impressions!

A close-up look at the footprint shows that it preserves the creases, ridges, and pebbly texture on the bottom (plantar surface) of this Canada Goose's foot.

We also found evidence of our mammalian friends on the track surface: guess who?

If you guessed wolf, you would be correct!

Grey Wolf trackway overprinting the multiple trackways of Canada Goose. Bonus question: was this wolf walking or moving faster than a walk?

While we waited for the arrival of our small ducks (we could hear some quacking in the distance) we made a few plaster of Paris replicas of the different preservational variations of the Canada Goose and the as-of-yet unidentified small duck tracks.

Small duck trackway being cast.

The track surface with plaster replicas (white patches) drying.

Making replicas of modern tracks is a really simple process, and it's something that anyone of any age can do. We use a fiberglass-reinforced plaster of Paris (Hydrocal FGR-95). I also add additional fiberglass matting to the backs of the replicas, as many of my track casts are long and thin. Field neoichnology casting is a cumbersome process: you have to haul out plaster, mixing containers, fiberglass mat (or chop, but that's a pain in the butt to work with) and garbage bags. You also have to haul the awkwardly-shaped plaster casts out of the field. However, I think it's worth it for bird tracks. We're getting mixed results with digital photogrammetry on small bird footprints, and one of the reasons is that they are often wet, shiny, and partially underwater. All of this extra reflection confuses the computer program, which "prefers" even, consistent lighting for all of the images used in making the 3D digital replica. Also, plaster replicas are cheap to make, and I'm an ichnologist on a very strict budget.

This brings me to Important Field Tip #4: Pack it in, pack it out. We mix all of the plaster in a container placed inside a garbage bag, and any plaster drips and slops are collected after they harden. We don't want to leave a trace while we collect traces.

While we were waiting for the replicas to dry, we saw that our small ducks had arrived!

This is a horrid picture, but viewing these ducks through my binoculars let me know that they are Green-winged Teals in their non-breeding plumage. They are a small brown dappled duck, but one was kind enough to rearrange its wing feathers long enough to show me the green patch.

This was a good day for ducks, but where were my shorebirds? We scanned every centimeter of this shoreline, crossed over this waste-deep body of water to a second projection of land and scoured that for shorebird prints, and came up with almost nothing. We saw really faint impressions of Spotted Sandpiper footprints, but they were made in such wet mud that they had all but collapsed in on themselves, leaving nothing but faint lines where the toes impressions should be. We were about to call ourselves skunked in the shorebird category when we came across this:

FINALLY!

It turns out there were a pair of Spotted Sandpipers at this locality, but they were being extremely sneaky with us. We turned every corner just to see them flying away: none were comfortable with us in their territory, and they were more or less avoiding walking in areas that would keep an impression of a footprint for more than a few minutes. This was a huge change from last year, when two Spotted Sandpipers took a short nap while I was taking photos of them. On our way back to the field truck at the end of the day, we found out the little buggers had doubled back on us and were foraging in the areas we had already prospected. This brings me to my final Important Field Tip: you can't control your wild study taxa. Some days they cooperate, while on other days they flip you the feathery Bird.


This was a typical field excursion, full of wins (great duck and goose tracks) and fails (the Thrashing of the Tire and my new gravel piercings). Regardless of the frustrating parts, it was great to be back in the field!

Until next time,
SW

P.S. - My thumb turned out not to be broken (yay!) but it was swollen and sore for a few days. Here is a picture the day after I landed on it. Luckily the blisters were just impact blisters - there were no embedded gravel chunks to remove.