This Bud's for You

This time of year could be hard on a squirrel. The last of the stored nuts are gone as are their favorite fruits and berries. To find food they usually have to go out on a limb.

In the early spring their main diet is tree buds which have a lot of stored energy for the year's growth.  To a squirrel this means good nutrition.  Once the buds are gone they switch to the tree blossoms.  We are seeing young squirrels out on the very tip of a branch, swaying in the wind.

Young squirrel reaching for  twig tips - REK

Like most animals they aren't too picky when they are hungry and even some herbivores like a little meat once in a while.  When food sources are scarce they will eat insects, mushrooms, grain and even bird eggs.  Birds? On rare occasions they will eat a bird or even a snake.

Squirrels will chew tree bark and twigs and no one knows why for sure as they can't digest cellulose.  They will use strips of tree bark in their nests but at other times they seem to chew just for the heck of it.  As rodents with constantly growing teeth they may be doing it to keep wearing their teeth down like a beaver.  We have a constant battle with ours chewing the painted shingle siding which covers an underlying concrete wall.  When I covered it with thin aluminum sheeting they chewed it!

Any skull or antler left in the woods for too long will have signs of squirrel chews.  The theory is that they are getting calcium which is otherwise missing in their diet, although it could be for tooth wear as well.  I leave an old deer skull on our deck which is chewed on daily but one squirrel still is chewing on our house.

Eastern gray squirrels are very territorial and will mark their area with urine and tree chews. They will chew bark and rub it with oral scent glands to mark their territory. A certified wildlife tracker friend spotted one of these marks on a large oak wolf tree in the middle of a field.

A final thought about what squirrels chew.  They are rodents.  Chewing is what rodents do.   They have rootless teeth that are constantly growing and need to be worn down.  It is not their problem, it is ours.

Bloodroot Bleeding

Sap oozing from cut leaf surface - Christine Chiu

On the Master Naturalist/Missouri Native Plant Society Wildflower Walk at Bull Creek we identified 54 species plus a few blossoming trees.  One of the most interesting if somewhat less showy now is the Bloodroot (Sanguinaria canadensis).   While they had already bloomed and were forming seed pods, they are always entertaining for their novel characteristics.

Bloodroot leaf - Click to enlarge

To my untrained eye it is its distinctive leaf with palmate veins and 5-9 lobes plus minor lobes that catches my eye.  They are both glabrous and glaucous, great words with a personal meaning.  Glaucous refers to a covering of a whitish powder or waxy coating like the stems of the common raspberry stems. Glabrous refers means "without hairs of any kind," an easy definition for me to remember.

Bloodroot Flowers - REK

The early spring flowers are short lived, 1-2 sunny days while using its energy to produce a fragrant scent.  They are notable for their marked variation in size, number of petals and even their appearance.  Generally white, they occasionally produce pink petals.



Bloodroot get its name form the color of the sap that extrudes from its cut surface.   This colorful liquid was used by Native Americans as a dye as well as an antiseptic, a property that has been confirmed as antibacterial by modern medicine.

Sap oozing from cut leaf surface - Christine Chiu

We have been known to dig up a root on occasion to demonstrate its colorful sap but Christine Chiu took this to another level.  She pointed out a leaf which had tiny orange-red dots along a cut edge that resembled tiny mites.  It had been  apparently chewed by a critter - maybe a squirrel needing antibacterial properties for an inflamed gum?  On close examination, the orange dots were sap extruding from the cut surface!

Bloodroot seed capsule

The story only gets more interesting.  Their blossoms are replaced by a green seed capsule that will fade to yellow within days.  Then it will do what all plants (and also all animals) spend their lives trying to accomplish, release its seeds for a new generation before fading until next year.  The seeds are round and their colors are variable.

While our human ancestors first developed agriculture around 11,500 years ago, ants have been at it for much longer.  Each Bloodroot seed has a tiny white elaiosome, a packet of energy with protein and lipids like a miniature energy bar from a quick shop.  Ants pick up the seeds and transport them to their underground nest, providing food for the colony while planting the seed for next year's crop.

Since discovering Christine's demonstration of the "bleeding leaf," I find myself pinching off a corner of a Bloodroot leaf occasionally, just to watch nature work its wonders.

You can read more on Bloodroot in this previous blog.

Pawpaw Egg

I began searching for the first butterfly eggs last week, focusing on the Zebra Swallowtail.  Unlike many other species, the Zebra lay their eggs only on one plant species.  We have only a few places where they grow usually as small trees, so most of their early leaves are accessible.



I started with a grove of 25 small pawpaw which has produced results in the past.  I searched all the accessible leaves without any luck.  One leaf held a small nondescript insect larva, possibly an early instar of a moth species.  While I was trying to photograph it, a spider appeared on the leaf edge.

Soon the spider crossed the leaf and inspected the caterpillar at length.  Apparently it didn't pass the taste test as it left it alone.  I was about to give up when I saw a Zebra Swallowtail fly through the grove.  I decided to sit and wait a while.

After 20 minutes a Zebra returned, landing on three different leaves for only a second.  After it flew on I checked the leaves - no luck.  After another 20 minutes it returned, landed on the same leaf it had checked out before and curled its abdomen under the leaf.  When it flew away I checked the leaf and was rewarded with my first egg of the year.

There are two lessons from this.  Sitting quietly in the woods is relaxing and you may well be rewarded with something special.  Also, I have way too much time on my hands.

High Hopes

Behind our house on the gravel I came across an ant determined to transport a dead fly back home.  I followed it 15 feet, trying to get ahead of it while keeping it in macro focus.  It is amazing how fast an ant can move when you are trying to keep up with it on your knees.

Lifting it over the rocks and a "log"

The strength of an ant is incredible and after watching this one I think the ant in "High Hopes" might just be able to move the rubber tree plant.*  What caught my eye initially was its lifting the fly over huge boulders and the large "log" above which was twice its height.

Pushing it down the "highway"

Traffic jam

The ant would push it ahead when possible, turning to pull it up over obstacles.  Once it got to the hose it pulled the fly up and pushed it ahead like it was on I-44.   Aside from having to slow down because of a traffic jam from its nest mates headed the other direction it was smooth sailing.  Suddenly it hit the forest exit and entered the leaf litter where I couldn't go.

James Trager** tells me "The ant is taking home the fly as a protein meal for the younger members of her colony, the larvae.  Your ant appears to be Formica biophilica, or a close relative. There are four species in Missouri that look rather like this."

I hope the nest mates appreciate the ant's focus and stamina and give it the rest of the day off.  It probably will tell them all about the old man that was stalking it obsessively with his camera.

* For our younger readers born after 1959, here is a refresher.
** We will be hearing more wisdom from James Trager at next month's MN meeting.  A little overview of our Missouri ant ecology is here. 

Snake Strike

Waiting to come inside - REK

This spring snake season open with the mid-March appearance of our resident Western Rat Snake stretched out by our front door.  It usually is quite calm, moving slowly away if we get within a few feet, otherwise quite content to rest, presumable awaiting the arrival of the next small mammal.  Unfortunately, it makes a good living at our rural house.

This rat snake, Pantherophis obsoletus, moves cautiously at what appears to be its top speed even when disturbed.  This is deceptive as demonstrated by recent research.  Contrary to popular belief, a rat snake can strike its prey with the same speed as a rattlesnake.

Research reported in Nytimes.com shows a video comparison of P. obsoletus against a cottonmouth (Agkistrodon piscivorus), and the western diamondback rattlesnake (Crotalus atrox).  This dramatic strike speed in the video is equivalent to a car going 0-60 mph in less than a 10th of a second.  You can then compare the strike speed with the human's reaction in this video.

Snake-bite Jon - REK

My only experiences with holding a rat snake began with control of its head while stuck on a glue trap.  A handy hint for country living - you can free a snake (and in our case also a bat) by applying vegetable oil to dissolve the glue.  While a rat snake is not venomous, its bite can hurt.  The message here is don't think you can grab one before it grabs you.

Thanks to Dave Shanholtzer for sending the link. 

Semi-smooth Green Snake

While working on a trash cleanup at Valley Water Mill I saw a long piece of pale green cable draped across some shrubs and green briar.  It turned out to be a beautiful 27" long green snake.  It patiently held still for pictures but tried to slither out of my grasp.  It was smooth to touch, unlike the Rough Green Snake (RGS), Opheodrys aestivus, that we find commonly in SW Missouri.  I confidently identified it as a Smooth Green Snake (SGS) Opheodrys vernalis, until corrected by Jay Barber, our honored conservation educator.

Hanging out in the shrubs - REK

Jay pointed out that although it felt smooth, on close inspection it had the keels that usually would make the body feel rough on stroking.  I could see them with magnification but still wasn't convinced.  I even mentioned this to a botanist professor friend who said it wouldn't be a SGS in Missouri.  Time to research it.



It turns out that the last SGS seen in Missouri was over 35 years ago and it is considered extirpated in the state.  Also my specimen would be one inch longer than the record length, while the RGS grows up to 45 inches.  Jay wins.




The RGS is a beautiful snake with an intense gaze.  It seemed at times to be listening intently to our debate, or more probably sensing our vibrations, squirming excitedly, but it may have been just wanting to get away.  It was docile, never threatening and even seemed to relax with time.  When we released it, it left slowly - reluctant to leave?  No, probably just worn out by its new friends.

Big gaping jaws - Youtube

RGS reportedly are found in moist lands close to water although this one was up on the prairie.  Sometimes called grass snakes, they frequently are found up on shrubs as in this video where they hunt for insects such as grasshoppers.  On first glance, its mouth looks too small to hold a larger insect, let alone swallow one whole.

Dead blue snake - Bull Mills 2015   REK

This research also solves another Bull Creek mystery.  We found this dead and desiccated snake last April and couldn't account for its color. 

"After death, green snakes turn blue in dorsal coloration. Yellow and blue pigments in the skin fuse to produce the bright green color in the living snakes. After death, the yellow pigment breaks down very quickly, whereas the blue pigment is more stable and remains much longer." Herpnet.net

3-14-2018 Addendum
It turns out that the blue is in the refraction of the scales, mixed with the yellow pigment that has broken down.  See npr.org 

Snake in the grass

Skull Identification

I received a plastic bag with a "gift," a skull with a request for identification.  Some one else might have considered this a threat or at best a bad joke.  Amy Short knew this would be welcomed, a find from her mother's yard.  There were no other clues to its identity, no lower jaw and only one residual tooth.  It had been chewed by other animals in need of calcium.  I was tempted to send it off for an expert opinion from Richard Herman, our local skull guru but decided to take a swing at it.  I got lucky because of several unique features.

It was obviously a herbivore with the absence of canine teeth and the large gap between the incisors and the molars.*  The canine tooth canal was long, 1.5" on a curve suggesting that it was not only a rodent, but one that used its teeth hard enough to require rapid growth.  While the rodentia family is large, including beaver, mice, rats and rabbits, the skull length of 3.5" eliminated a lot of these.

Looking over the choices in Wild Mammals of Missouri (Schwartz) I came across the perfect fit.**  This skull belonged to a woodchuck, a.k.a. groundhog, Marmota monax.  I have been trying to trap the ones that are undermining our century old barn without luck for 3 years, and here was the skull, the ultimate irony.

The key was the length of the skull, but first the rodent identification.  This site from Cornell.edu gives the basic features identifying it as an herbivore by the absent canines and large gap between the incisors and molars.  The long incisor roots suggested unremittingly growing incisors, a characteristic of the Order Rodentia.


Once identified as a rodent in Missouri, the skull length narrowed the field.  It wasn't rounded like a beaver, too large for a rabbit and only a few species are left.  To quote Wild Mammals of Missouri,  "It is easily distinguished from other skulls...by the following characteristics:"

• Large size
• Flat skull when seen in profile
• Postorbital processes projecting at right angles to the length of the skull
• Depressed area between the postorbital processes 
• Prominent auditory bullae indicating hearing acuity.

 *For the basics of identifying carnivore, herbivore and omnivore, go to Cornell.edu.

**  Animal Skulls by Mark Elbroch is the ultimate source, very detailed with lots of keys.  Wild Mammals however is a great local resource and has dental guides and measurements that works for almost all of our Missouri skulls.

Pawpaw Flowers

Pawpaw flowers in full bloom - REK

This is the time of year we start monitoring the pawpaw flowers.  Sudden freezes turn them into shriveled dark brown blobs, robbing them of the chance to make fruit.  It is a miracle that we ever have any pawpaw trees, let alone fruit.  Their fruits are popular with squirrels, raccoons, and bears.  In season we see bear scat filled with seeds, the pawpaws' transportation out of the neighborhood.  Since their fruit are challenged by late frost, this method of propagation is hazardous.

Pawpaw flowers, fresh, dead and frost damaged - REK

Pawpaw, (Asimina triloba) have several survival techniques.  Their main method is to reproduce by suckers, roots extending out to establish trees nearby in an expanding community.  Left alone they could cover a large area but as a forest matures over years around them, their expansion is controlled.

Like other species producing dark brown to purple flowers, they rely on a smell of rotting flesh to attract pollinators, not butterflies but flies and other species attracted to the odor of death.*  Their flowers meanwhile are pollinated in a hit and miss fashion by flies, beetles and other species.  In some limited attempts to grow pawpaw commercially, growers actually hang dead fish and other lures to attract these morbid pollinators to their trees.

Bud ready to flower

We have noticed over the years that the flower blossoms develop and open up sequentially over 4-6 weeks in the spring.  Currently we have dried shriveled flowers killed by frost 3 weeks ago as well as recently stunted blossoms from the freeze a few days ago.  On the same tree are unopened buds both ready to open next to tiny emerging flower buds, the whole spectrum on a single tree.

Fresh flower and small new flower bud - REK

The early blooming pawpaw has thus found a way with dealing with these setbacks by spreading its flower buds over more than a month.  While observing this budding over time, we haven't noticed whether it ends when the frosts stop.  It is possible that this continuing flower bud propagation is the plant's response to frost damage.

*Further information on Pawpaw odors is in this paper.
Previous pawpaw blogs have covered Zebra Swallowtail eggs, the  butterfly's premature delivery and the Asimina webworm moth that lives curled up in pawpaw leaves.

Dusky Skippers Puddliing

Puddling party in the valley - REK

Juvenal's Duskywing - REK

We are seeing lots of Duskwing Skippers the last week, clustered in groups of 50-100 plus gathered on dry sand in our gravel drives.  These are the Rodney Dangerfields of the butterfly world and some would even go so far as to separate them from butterflies altogether.  The duskywing skippers are notoriously hard to identify by species and only the fact that I was seeing such large numbers at scattered sites made me curious enough to the trouble to ID them.

 These are all Juvenal's Duskywings, Erynnis juvenalis.  They  are nearly identical to
 Horace's Duskywings and both were named for Roman poets for unknown reasons.  The marking details separating the two species are very minute, one requiring pulling the forewing forward to expose two tiny white apical spots, cumbersome for me and I suspect embarrassing for the butterfly.  From now on I will confidently call them Dusky Skippers and skip on to the next species.

Juvenal's Duskywings fly earlier in the year than Horace's.    Juvenal's was one of the first North American butterflies to be described.  They were initially associated with dry, sandy regions with shrub oak but are found anywhere in the eastern US where their caterpillar host plant oaks occur.  Oaks occur all over our land so they have a lot to choose from.

E. juvenalis caterpillar -  Bob Barber CC

Males will cling to branches along the edge of woodlands and patrol for females.  Eggs are laid on early oak leaaf buds or seedlings where their caterpillars will  feed on leaves and rest in nests of rolled or tied leaves.

  Tom Murray

 Puddling or mud-puddling behavior is observed in lepidoptera and a few other insect species.  It is a way for them to collect minerals such as salt similar to what sweat bees do landing on our skin in summer.  Some species will do this on animal dung, presumably collecting ammonium.  These gatherings are predominately male as they collect sodium and amino acids which they then transfer to the female as a "nuptial gift" delivered with their spermatophore during mating.  It is common to see several species puddling together in the summer.


When I began writing this I suddenly noticed something else about the puddling photograph.   While the Duskywings wingspan measured less that 1.5" there was something even smaller on the sand.  See if you can spot them in the picture at the top.

 

There are two tiny black moths with multiple white spots on their wings.  These are Mournful Thyris, Thyris sepulchralis with a wingspan of less than an inch.  While most moths are out at night, these are day flying moths that feed on flower nectar and are noted for collecting fluid on moist sand.  Our sand appeared dry to sight and touch but many species shoot fluid out their rectum to moisten the area and dissolve the salts for absorption.  (Note to self - wash hands after testing sand).

One photographic trick is to pour a little salt water on the ground and wait for butterflies to puddle for the camera.  Some photographers suggest placing a decoy of a dead butterfly or even a piece of colored paper to attract species in the neighborhood.  A naturalist, most likely but not necessarily male, may chose to supply ammonium in the form of urea from a convenient resource. 

Find the moths?  Click on this picture.

Abbot's Sphinx Moth

Abbot's Sphinx Moth on the screen, its abdominal tip in its characteristic upright position - REK

I was closing the window one early morning at Bull Creek when I saw a dry leaf stuck to the inside screen that hadn't been there the night before.  It turned out to be a very cold Abbott's Sphinx Moth, Sphecodina abbottii.  How it managed to pupate and emerge as an adult in the house is beyond me.  Their usual time is May to June in most of its range and the males are reported to fly around dusk, the females flying near midnight.

Note glimpse of the yellow patch on the covered hind wing - Jon Rapp

Peterson's guide describes it as having deeply scalloped outer wing margins with swirling black lines.  It has a bright yellow patch on the basal hind wing that doesn't show in pictures with the wings folded at rest.  The abdomen ends in an unusual 3-pronged tip that it holds upright.  I tried to photograph it later in the day but the overcast sky dulled its colors so I turned to Jon Rapp as usual.

 First instar - Jo Ann Poe-McGavin 

 Last instar -  Jo Ann Poe-McGavin

The larvae feed on grape species, Vitis and Ampelopsisare.  They are equally cool looking, going through dramatic changes with each molting.  As described in Bugguide:

Knob as an "eye" - REK

"Larvae start out green with a horn on the final segment. Middle instar larvae are whitish to blue-green with dark faint cross-stripes and the horn replaced by an orange raised knob on the last segment (A8). The last instars may be either brown with a "wood-grain" pattern or brown with ten pale green saddles along the back. In these late instars the knob resembles an eye."

Note the 3-pronged furry abdominal tip held upright - REK

I kept my specimen in the refrigerator to get a better sunlit picture of the antennae.  It is described as flying with a buzzing noise, resembling a bee with its flashes of yellow.  Holding it, I could feel the buzzing as it warmed up its flight muscles, its oval body impossible to grip until it made its buzzing escape into the wild.  A much better fate than clinging to our screen, looking longingly at freedom.

Released, just before flying off - REK

 Addendum:
Not to be out done, Kevin Firth sent me his gorgeous picture of a new (to us) moth he photographed at Rocky Barrens CA recently.  This is likely Kent's Geometer, Selenia ketaria.