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More Exciting Crayfish News!

As incredible as it may seem, we have another recent development relating to the stream crayfish of the Ozarks. First, all of our stream crayfish were moved from the genus Orconectes to Faxonius. Now we have two new species! 

Fetzner Jr, James W., Taylor, Christopher A. (2018): Two new species of freshwater crayfish of the genus Faxonius (Decapoda: Cambaridae) from the Ozark Highlands of Arkansas and Missouri. Zootaxa 4399 (4): 491-520, DOI: https://doi.org/10.11646/zootaxa.4399.4.2

In a study published about a couple of weeks ago, Doctors Fetzner (Carnegie Museum of Natural History) and Taylor (Illinois Natural History Survey) split Faxonius eupunctus into three species. F. eupunctus was not a species I expected to be split. It is (or was) limited to three adjacent drainages and I’ve never noticed any difference in the specimens I’ve observed. For what it’s worth though, I wasn’t expecting any differences and that lack of expectations may have kept me from noticing anything.

After I saw the title of the study, but before I read the abstract, my first thought was that F. neglectus had been split again—a split into at least three species had been proposed several years ago, though that doesn’t appear to have been adopted/accepted. Nor would I have been surprised if it were one of the species that is widespread in the Ozarks and varies greatly in appearance from drainage to drainage (F. luteus, F. punctimanus, F. ozarkae.)

But no, F. eupunctus it is. The new species are named F. roberti (in honor of Robert DeStefano of Missouri Department of Conservation) and F. wagneri (for Brian Wagner of the Arkansas Game and Fish Commission). The suggested common names are Spring River Crayfish and Eleven Point River Crayfish respectively.

F. eupunctus (formerly) occurred in the Eleven Point, Spring and Strawberry Rivers of southern Missouri and northern Arkansas. When I saw that they had been split, I was expecting that they simply separated the populations of each of those three rivers into distinct species. I should be so lucky.

The population that occurs in the Spring and Strawberry Rivers was split and is now known as F. roberti. That’s the easy part. Once you get back to the Eleven Point, things get trickier.

F. roberti, October 20, 2010, Barnes Road Bridge, Strawberry River, Sharp County, Arkansas.

F. eupunctus is now restricted to the Eleven Point, but F. wagneri also occurs in the Eleven Point, though they specified the 54-mile stretch from Greer, Missouri to Birdell, Arkansas. F. eupunctus also occupies that stretch of the Eleven Point but extends upstream of Greer at least as far as Cane Bluff Access, probably further. Therefore, over most of F. eupunctus’ range and all of F. wagneri’s range, the two species occur together.

To further complicate things, you have to get into the weeds to differentiate between them. Let me quote the study on how to separate F. wagneri from the other two (we don’t have to worry about F. roberti since it doesn’t occur with the other two):

Faxonius wagneri can be differentiated from both F. eupunctus and Faxonius roberti sp. nov. by using the male Form-I and Form-II gonopods, the shape of the chelae, and the female annulus ventralis. In F. wagneri, the terminal elements of the first pleopod are almost twice as long as those in F. eupunctus and F. roberti, with the tips of the appendage reaching the posterior base of the first perieopod when the abdomen is flexed forward, whereas, in the other two species, these elements only reach the base of the second pereiopod. The species also possesses two spines on the dorsal side of the merus of the first pereiopod, which helps distinguish it from F. eupunctus.

Clear as mud, right? I’m sure that any astacologist knows exactly what it means, but I’m out of practice (that’s my story and I’m sticking to it) and had to take some time to decipher it. I don’t know that I’ll ever be able to use any of that to make a positive ID in the field.

Let’s unpack things and see where we stand. Gonopods are a pair of swimming legs that have been modified for sperm transfer and come in two forms, one that is capable of reproduction (Form I) and one that can’t (Form II).

A male crayfish typically molts into Form I in the fall and back to a Form II in late spring/early summer. The Form I gonopods are widely used to distinguish between similar species, but you must have the crayfish in hand, it must be a male (obviously) and you either need very good eyes or a magnifying glass of some sort.

Form II Gonopods (from an F. luteus)

The chelae are the claws, which are clearly visible in most photos. But unless I missed it, the study doesn’t clarify how the chelae actually differ between the two species. For the time being at least, that’s not a viable way to make an ID.

The annulus ventralis is the female crayfish’s sperm receptacle. Here again, you’re going to need the crayfish in hand before it’s of use in making an ID.

This image is from an ovigerous female photographed at Greer Access in January 2013 and identified at the time as F. eupunctus. Unfortunately, I find that comparing the photo with the annulus ventralis images in the study to be inconclusive. The top half looks more like F. wagneri, but the lower part more like F. eupunctus (look at the seam in the middle.)

Pleopods are the swimming legs and the first pair is modified into gonopods, while pereiopods are the walking legs, including the pair with the claws. So, this is describing the details of the gonopods and we addressed those a couple of paragraphs earlier.

The merus is a segment of the cheliped (the walking leg that ends in the claw), the second from the claw.

Source: Natural History Museum of Los Angeles County

Dorsal simply means the top side, so we’re looking for spikes on the top side of the second leg segment back from the claw.

These merus spines are the most promising feature for use in making an id in the field or from a photo. F. wagneri has 2 spines in 88% of specimens examined, while 81% of the F. eupunctus specimens had a single spike. Those percentages leave room for doubt but would allow at least a well-educated guess.

I’ve gone through photos from the Eleven Point that I had originally identified as F. eupunctus and found that I can sometimes distinguish the number of spikes. Based on this, I’ve apparently found and photographed both species in the past, though as we established above, the spikes can’t really give you an absolute ID, just a strong “probably.”

You can get a clear view of the spikes (or rather spike) on this crayfish, so that means it’s more than likely an F. eupunctus. On the other hand, the crayfish in this next sequence has two spikes so the odds favor it being an F. wagneri.

The five photos above were all taken in the same location (1 mile downstream from Greer Access) on the same day. The F. eupunctus is much darker and more greenish than the F. wagneri, but I think that this fits within the normal range of variability. I’ve seen crayfish that I believe to be F. eupunctus which were colored very similarly to the F. wagneri above. For example:

F. eupunctus, June 19, 2011, Cane Bluff Access, Eleven Point River, Oregon County, Missouri.

So I don’t see how coloration can be used to distinguish between the two species. I’m anxious to get back to the Eleven Point and put in some time looking at crayfish to see if I can get a better handle on identifying them.

An important thing to keep in mind is that F. eupunctus was already on Missouri’s Conservation Concern list. In fact, the species was beginning to receive attention as a possible Endangered Species candidate, which led to this study. Now that the species has been split into three, each population is, of course, smaller and more range restricted than the original.

This only increases the vulnerability of each. All three will undoubtedly be placed immediately on the Conservation Concern list if they aren’t already. And if F. eupunctus alone was being considered for Endangered Species status, the split should make all three candidates.

This is especially true since F. neglectus has been introduced into both the Spring and Eleven Point watersheds. F. neglectus chaenodactlyus, native to the adjacent North Fork drainage, is well established in the West and South Forks of the Spring River and appears to be displacing F. eupunctus (now F. roberti).

In the Eleven Point, the Missouri Department of Conservation discovered a population of F. neglectus neglectus in Jolliff Spring Branch on the Barren Fork, in the upper reaches of the drainage. F. n. neglectus is native to the Spring/Neosho River basin. F. eupunctus has only been recorded from the lower reaches of Barren Fork, though it occurs throughout the main stem of the Eleven Point (this is some 15 miles upstream of the described F. wagneri range.) At the time of the report (2011), the invasive population hadn’t yet come into contact with F. eupunctus. But it’s likely only a matter of time until this occurs if it hasn’t already.

A friend of mine tends to get irritated when species are split, believing it to usually be unnecessary. But this is a good thing from my perspective. It gives me a crayfish project to work on, something I’ve been without since I finally met my goal of photographing all the stream crayfish of the Ozarks. As I said before, the Eleven Point is close at hand, so I expect I’ll be making a few trips down there before long. All you crayfish better hide your genitals.

 

References:

Crandall, K.A. & De Grave, S. (2017) An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list. Journal of Crustacean Biology, 37 (5), 1–39. https://doi.org/10.1093/jcbiol/rux070

DiStefano RJ, Imhoff EM, Swedberg DA and Boersig III. TC (2015). An analysis of suspected crayfish invasions in Missouri, U.S.A.: Evidence for the prevalence of short-range translocations and support for expanded survey efforts. Management of Biological Invasions 6(4):395–411.

Fetzner Jr, James W., Taylor, Christopher A. (2018): Two new species of freshwater crayfish of the genus Faxonius (Decapoda: Cambaridae) from the Ozark Highlands of Arkansas and Missouri. Zootaxa 4399 (4): 491-520, DOI: https://doi.org/10.11646/zootaxa.4399.4.2

Imhoff, E.M., Moore, M.J. & DiStefano, R.J. (2012) Introduced alien ringed crayfish (Orconectes neglectus neglectus Faxon, 1885 ) threaten imperiled coldwater crayfish (Orconectes eupunctus Williams, 1952) in the Eleven Point River drainage, Missouri, USA. Aquatic Invasions, 7, 129–134. http://dx.doi.org/10.3391/ai.2012.7.1.014

Larson, E.R. & Magoulick, D.D. (2008) Comparative life history of native (Orconectes eupunctus) and introduced (Orconectes neglectus) crayfishes in the Spring River drainage of Arkansas and Missouri. American Midland Naturalist, 160, 323–341. http://dx.doi.org/10.1674/0003-0031(2008)160[323:clhono]2.0.co;2

Magoulick, D.D. & DiStefano, R.J. (2007) Invasive crayfish Orconectes neglectus threatens native crayfishes in the Spring River drainage of Arkansas and Missouri. Southeastern Naturalist, 6, 141–150.
http://dx.doi.org/10.1656/1528-7092(2007)6[141:icontn]2.0.co;2

Pflieger, W.L. (1996) The Crayfishes of Missouri. Missouri Department of Conservation, Jefferson City, pp. 152.

Rabalais MR, Magoulick DD (2006) Is competition with the invasive crayfish Orconectes neglectus chaenodactylus responsible for the displacement of the native crayfish Orconectes eupunctus? Biol Inv 8:1039–1048

 

 

A Differently Tailed Kite

Swallow-tailed Kites are residents of South America, but each summer a part of the population comes north to breed. They nest in Florida, the Gulf Coast to Louisiana and the Atlantic to South Carolina; they’re considered vagrant throughout the rest of the United States east of the Rockies.

Last August, one showed up at Duck Creek Conservation Area north of Puxico. That’s only an hour’s drive, so Dayna and I were on the hunt the first day we had off. We struck out, though we did see plenty of other birders. The kite had brought us bird-nerds out in force.

The bird continued through the week and I made a solo trip back the following Friday. This time it took zero effort to find it. Parked beside Hwy 51, a fellow birder (Hey Jethro!) was watching the kite when I arrived.

I parked behind him (Jethro, not the kite) and began taking photos. Two of the more common Mississippi Kites joined the Swallow-tail hunting over a field beside the road. Mississippi Kites are beautiful birds, but they were drab next to the Swallow-tail, all dapper in his crisp black-and-whites. Both species are beauty and grace on the wing.

Jethro had to go to work and the roadside was all mine. I watched the kites for a half an hour as they devoured cicadas and dragonflies, all captured while performing their aerial ballet. The birds were a little too distant for good photos—though I did at least have the sun at my back—and a deep, water-filled ditch kept me from getting closer.

I pulled up a map of Duck Creek and quickly realized that a secondary road, if it was open, would lead me to a parking area behind the kites. Ten minutes later found me in that parking area, but a second ditch tried to throw another obstacle in my path. This ditch, however, was a trickle compared with the first and I tiptoed my way past.

I made it to the field, but the birds had drifted north. They were foraging, so I held position, they drifted back my way and were soon overhead. I’d lost the favorable light though and while I tried to move enough to overcome this, the birds moved away again.

Hot, thirsty, and crawling with ticks, I called it a day. My camera held over 400 photos and I hoped for some nice shots.

Some of the photos were OK, but they didn’t meet my expectations. Disappointed, I didn’t process any of them until I began writing this post.

Once I did, they weren’t as bad as I thought and I caught some interesting behavior. This Mississippi Kite has caught a cicada, which makes me appreciate kites even more.

This sequence of the Swallow-tail pursuing and capturing a small insect that I can’t identify was cool too. That tiny black dot in front of the kite in the first image is the insect; he’s eating it in the second.

Two days after I saw the kite, he was gone. I don’t know why this bird was in Missouri, far from its normal range. Probably a case of post-breeding wanderlust, something that you see in many species besides kites.

I’m going to the Gulf later this year, so I may get to see and photograph another Swallow-tail, but the chance to do it here at home is unlikely to come again.

Our Other Immigrant Sparrow

Everyone is familiar with House Sparrows, right? Even non-birds must be aware of them since the pestiferous little bastards are everywhere.

North America’s first encounter with this species took place in Brooklyn in the early 1850s. A number of birds were released in the hope that they would stop an outbreak of linden moth caterpillars. But intentionally introducing these bird led to unintentional consequences. Oh, were there consequences.

Accustomed to living in proximity to humans, adaptable, and aggressive, those first birds thrived and spread. Supplemented by later releases in San Francisco and Salt Lake City, they soon occupied the entire continent excluding northern-most Canada.

But we have another introduced sparrow, one that is probably unknown outside the birder’s circle. This bird, the Eurasian Tree Sparrow, was introduced in April 1870. Twelve birds (or twenty, depending on where you get your information) from Germany were released in St. Louis’ Lafayette Park. This was part of a misguided effort improve the native bird life and provide a “familiar face” to the large immigrant population, homesick for the old country.

Despite being much less aggressive than the House Sparrow, those twelve birds still managed to establish a breeding population, albeit on a much smaller scale. There are now about 15,000 of them, mostly in the St. Louis area but also spreading north along the Mississippi River into Iowa and Illinois. Ironically, when the House Sparrow reached St. Louis, they drove their more timid cousins from the downtown area and they now occupy mainly residential and rural areas. 

House Sparrows are the obnoxious neighbors with the loud truck, louder music, and drunken parties. The ones that take a piss on your prize roses. Meanwhile, Eurasian Tree Sparrows are the quiet, polite neighbors whose presence you barely notice. Unlike the House Sparrow, their environmental impacts have been minimal, causing little or no damage to native bird populations. For those reasons, I can accept them alongside our native birds, while I detest House Sparrows.

I photographed both birds pictured here at the Riverlands Migratory Bird Sanctuary in St. Charles, north of St. Louis. The first photo is the very first frame of a Eurasian Tree Sparrow I ever shot and I really like the image. The bird was next to the Riverlands’ Visitor Center where I found him under brutal conditions.

It was 10°, but the wind chill was 20 degrees colder and even dressed warmly, I could only endure for 10-15 minutes before returning to the car. The wind and cold made my eyes water, which ran down my face before freezing in my mustache, along with the condensation from my breath. This despite wearing sunglasses and a balaclava. It was fantastic weather if you were a Polar Bear or just like freezing your noogies off, and I’m in no hurry to repeat the experience!

 

References:

Snow Bird

 

One evening in early February, I filled the bird feeders one last time before the day faded into darkness. Cold gripped the Ozarks and the birds would appreciate the easy calories. On a lark, I sat in the truck, using it for a blind to wait for my customers to return. As the minutes passed, snow began to fall, but strangely, no birds came back to the feeders. They usually come pouring back from the trees as soon as I walk back towards the house.

Finally, just before I called it quits, I saw movement in the Eastern Redcedar at the yard’s edge. A Fox Sparrow materialized in the brush next to the Redcedar, then another and a third. The snow fell more heavily and the light deteriorated even further, but I shot a few photos anyway. Had I been shooting film, I would have passed on the opportunity, but digital costs nothing and I shot away.

The photos were dark and noisy. Brightening the image created even more noise. I almost discarded my work at this point but decided to run a de-noise filter first. And I’m glad I did. The falling snow and painterly feel combined to create a rather attractive image. At least I think so. I’ll take all the Happy Accidents I can get.

White-tailed Goldfinch

Does this goldfinch look odd to you?
 
 
I know goldfinches’ tails are white with black terminal markings, but this one seems to have a lot of white. I keep waffling back and forth on whether I’m overreacting by calling him leucistic (a genetic mutation that causes melanin pigments to become washed out and pale) or if there is a more prosaic explanation.
 
Still, I’ve watched hundreds, if not thousands, of goldfinches at feeders over the years and this bird stands out, so I don’t think I’m making something from nothing. This bird’s tail is abnormally white.
 
 
The yellow on the rump is normally more pronounced but it’s faded and hard to see here. The black areas at the end of the tail are usually more extensive as well. This missing black is the real reason the tail looks so damned white to me.
 
Compare his tail with this one from a “typical” goldfinch.
 
 
This one has more black, but it’s hard to say for sure because the wings cover a significant part of the tail when folded back like that.
 
 
So, let’s break this down:
 
  • The bird in question is molting (look at his forehead.) My first thought was that the molting process was causing the tail to look so white. But once I learned that goldfinches don’t replace their wing or tail feathers during their spring molt, I tossed that hypothesis.
  • Our bird also holds his wings in a very loose, drooping posture, where most goldfinches keep them folded across the back, In fact, I couldn’t find a single photo of a goldfinch holding its wings in this way. But even in in-flight photos, with the tail exposed, none have tails that look that white. This posture does allow more of the white part of the tail to be seen. But that doesn’t account for the reduced black at the end of the tail.
  • That brings us to the possibility of leucism. All the leucistic goldfinches I’ve found online have been affected over a larger area of the body, usually from the neck down, but including the head on occasion. I did, however, find one account of a bird with a white patch on the top of his head and no other abnormal coloring. I also found other species of birds with leucism that only had white tails and they looked similar to what we have here.
  • According to Feederwatch, occasionally a bird will lose feathers in a close call with a predator. When this happens the new feathers sometimes grow in white and then change back to the normal color at the next regular molt. This kind of white coloring looks like leucism but is not and most often happens in the tail, causing a bird that lost its tail feathers to a predator to have an all white tail. that’s not the case here since our bird doesn’t have an all white tail, instead still having black in reduced amounts.
 
 
So where does that leave us? Despite the fact that leucism isn’t that common—Feederwatch has recorded 1600 cases from 5.5 million birds—I believe this bird is partially leucistic. Unless I’m missing something, the evidence seems to point in this direction. If any of my half-dozen readers (you can’t hide, I know you’re out there) have another take, I’d be thrilled to hear from you.

References: