Wednesday, November 25, 2015

Eastern Chipmunk

     The Eastern Chipmunk (Tamias striatus striatus) is the familiar striped ground squirrel we encounter on many of our woodland walks. Since they will soon become less common, going into torpor and sleeping for large parts of the winter, I thought I'd write about them now. They are not true hibernators, waking every few weeks to feed on warmer winter days, but most are hidden in their underground burrows by December.
     As mentioned earlier, these are ground squirrels, the only members of the subgenus Tamias and having 2 fewer teeth than other chipmunk species. Almost all chipmunk species are found in North America, the only exception I'm aware of being the Siberian Chipmunk. The sole local representative we have is the Eastern Chipmunk. Being squirrels, they all can climb, though they prefer to stay on or under the ground. I've seen as many as 4 at the same time up in a single Bird Cherry tree picking fruits however. The photo below shows one in the low branches of a shrub.

An Eastern Chipmunk stares at me from its tree perch.

     These are small rodents, usually under 10 inches including the tail, and weighing under 5 ounces. Eastern Chipmunks are strictly diurnal and are extremely active during their waking hours. They are also quite vocal, chipping, chirping and otherwise sounding off in the woods. Some think they're called chipmunks because of the chipping sounds they make, but it is more likely that their common name is derived from either Ottawa or Ojibwe words that were corrupted to "chipmunk." Their Native American Indian name is supposed to mean "one who descends trees headfirst."
     Their stripes are a distinguishing feature and there are several legends concerning how they got them. My favorite is a Haudenosaunee (Iroquois) tale relating how the chipmunk, never lacking for something to say, challenged a cocky black bear. The bear was proud and thought there was nothing he could not do, so the chipmunk challenged him to keep the sun from rising. When the bear failed to do so, the chipmunk loudly chattered with mirth and told all the other animals of its failure. The bear was so angered that it pinned the chipmunk under its paw, proclaiming that though perhaps it couldn't stop the sun, it could keep the chipmunk from ever seeing another sunrise. The chipmunk begged for a chance to say a last prayer, if only it could get a bit of breath to do so. When the bear raised its paw ever so slightly, the chipmunk ran for its burrow. The bear was quick enough for one last swipe with its claws, leaving 3 striped scars forever on the chipmunk's back.
     Because Eastern Chipmunks are not true hibernators, they need to collect much food to have ready over the winter. They cache large stores of nuts, seeds, and bulbs for their regular forays to get food. They keep several stores at the ready, just in case another animal finds their hoard and steals it.
     These underground stores require a great deal of food collecting. They do this by carrying the seeds and nuts they find in cheek pouches back to their larders. They can expand their cheeks up to three times the size of their heads, filling them one cheek at a time. They can carry 5 peanuts at a time. The famous naturalist John Burroughs studied one individual chipmunk over three days and said it carried off "...5 quarts of hickory nuts, 2 quarts of chestnuts, and a quantity of shelled corn." That's right, in THREE days. For a short video of one collecting seeds and nesting material, please check out this video from the Capital Naturalist YouTube Channel:

     Because they are storing the seeds and nuts all in single locations and destroying the seeds as they need them, they are not very good at dispersing seed. They do however also eat a fair amount of mushrooms and fungi and are thought to disperse those spores quite a bit. Chipmunks also occasionally eat insects and raid birds nests, but not that often.
     Chipmunks are very vociferous. They make a variety of calls in addition to the alarm call we often hear when one spots us and takes off running for its burrow. One such call is only given for a very short period of time (maybe a day) when the female is in estrus. For a short video of one giving this call, check out the following:

     Female chippies mate with multiple males before giving birth to up to 8 (but 3-5 is much more common) young. Gestation is about 35 days and it takes about 40 days for the young to be weaned. They normally mate once a year around here, but we're far enough South for second brood occasionally. If lucky, they might make it to 8 years old, but 1-2 years is much more the norm. 
     Chippies have lots of enemies. Foxes, hawks, owls, large snakes, weasels, and especially cats get many of them. Cats are a particular danger because chipmunks are creatures of habit. They will use the same logs or trails to run on almost every time. Cats figure this out and stalk those routes. The cat might miss several times, but the chipmunk will keep using that little route over and over again, often ending up as a cat kill to bring back to its owner, to eat, or just dump after playing with it a while. They can spend a lot of time ambushing the same area repeatedly that many of our native predators cannot afford to do. 
     I really like these little ground squirrels, always have. These days I occasionally find their greedy little raids a bit much (I mean how much bird seed from the feeder can it really eat?). I also hate it when they find my wild strawberries and serviceberries, as they make off with tons of them. They seem to know that they're safe under the net I put over the plants to keep the robins and starlings at bay on occasion (I've since just given up even trying). But overall I love watching them in my yard. 

A recently weaned chippie wanders away from its burrow for the first time.

     We've been lucky enough to see them raise their young at my house, and there might not be anything cuter. I must admit that in my misspent youth we did some dumb things including trying to catch them. For some reason, we never got bit, though we managed to catch a few, I'm not sure why. I also remember one particular day when one ran up inside the pants leg of my father's best friend and hunting buddy when trying to escape a hunting dog. Yep, that was funny...  So I'l  wish our chippies a good, long sleep, but expect to see their high jinks again in the spring. 

Wednesday, November 18, 2015

Osage Orange: Living Fences of Bow-wood and Horse Apples

The pointed leaf, spiny twigs, and unique fruit of the Osage Orange

     Among the most unusual and recognizable of fruits is the Osage Orange (Maclura pomifera). It goes by a variety of names: Hedge Apple, Horse Apple, Monkey Ball, Yellowwood, Bois D'Arc, Bodark, Bodock, and Bow-wood for examples. It is actually not native to our region, but has been widely planted throughout North America, in all 48 contiguous states and parts of Canada. In fact, I've been told that the national champion is located in Alexandria, Virginia, at River Farm and was a gift from Thomas Jefferson.
     Originally this small tree (it rarely gets to 60') was mostly limited to the Red River drainage in Oklahoma, Texas, and Arkansas. Had it not been for the many virtues that people found in it, it may have eventually gone extinct. Many believe that it originally had its seeds dispersed by megafauna such as giant sloths, mammoths, mastodons, and gomphotheres that fed on its fruits but are now extinct. Very few creatures now feed on it, despite its large fruits, and so it has no real way to disperse its seeds these days. Although squirrels (mostly fox squirrels) and horses (thus the name Horse Apple) occasionally eat them, they do not do so very often and are very inefficient at distributing viable seeds. This is the only surviving member of the Maclura genus. 
     Being dioecious, with male and female flowers on separate plants, only the female trees produce the peculiar fruits. However, it appears that female trees can produce fruit even in the absence of male trees. The fruits produced however lack actual seeds and are not viable. This large, compound fruit is referred to as a syncarp botanically. It looks somewhat like a grainy grapefruit and has a slight citrus smell. The insides are not edible however, exuding a latex substance that is bitter and might even give some people a rash. 
     The tree has yellowish to orange wood that is extremely strong, rot resistant, and flexible. It also takes a polish very well and has long been considered one of the finest woods for bow staves even to this day. Since the tree often grows gnarled and crooked however, it is not always easy to find a straight and knot-free piece that is long enough for use in archery. 
     It is its use for superior bows that gives it several of its common names. Bois D'Arc means "wood of the bow" and was the French term for it upon seeing the Native American Indians use of it. That led to corruptions of that name so that it is sometimes called Bodark, Bodock, and Bow-wood.  The most common name of "Osage Orange" came about by its favored use as a bow material by the Osage tribe. They were famous for their superior and valuable trade bows.
     But they were far from the only people to use if for bows. Other tribes doing so included the Pima, Omaha, Pawnee, Ponca, Seminole, Tewa, Kiowa, and Comanche. Some think that it was so valuable that it was planted far outside its natural range and saved from extinction by the native people. They had other uses for it too. The Pima used for a yellow dye for example (and the tree is sometimes referred to as Yellowwood, though some other trees are also). The Comanche used it for an eye wash as well. 

The twigs and young branches often grow intertwined and are spiny

     But it was some of its other properties that led to it being so widespread. The tree, for example, is very tolerant of a wide range of soil conditions. Not only do the twigs have spines, but each leaf has a spine too. They grow quite fast in the sun, but do not spread very far by seed so as to invade fields. Rather, they can grow very thickly and reproduce next to each other by cloning and sucker growth. They soon can make an almost impenetrable and spiny wall that can be trimmed and pruned. Osage Orange was therefore planted as living fences and windbreaks on many farms before the advent of barbed wire. They could keep stock from wandering, but since they were short, did not shade out too many crops or forage areas. Their use as these living fences and natural wind breaks (promoted heavily in some places) helped this tree spread far and wide.

Each leaf typically has a spine at its base

     These traits were recognized long ago. Francis Porcher in his Civil War treatise on useful plants in the Confederate South praised its use for living fencing. He stated that its presence would "double the real value of any farm it surrounds" while keeping the lands safe "from all thieves, rogues, dogs, wolves, etc." 

An old living fence now has gaps and has fruits strewn underneath and along the whole length of the hedges they now form

     The close-grained and yellowish-orange wood was very much valued, and not just for bow staves. It is considered to be twice as strong as white oak. The timber is extremely rot resistant, even when in contact with ground. Early on, the wood was used for wagon wheels, rail road ties, fence posts, and even police billy-clubs. The timber has some of the highest BTU ratings of any North American wood, so it burns long and extremely hot. Its tendency to spark and throw embers a very far distance should however be taken into account if using it that way. 

The leaves have a slender point and turn yellow in the Fall

     Country lore also has it that the large fruits are a good insect repellent, especially for roaches. Tests however have shown that to be true only for very concentrated extracts from the fruit, so the Osage Oranges themselves would not be very useful for that endeavor. 
     Though few creatures feed on the Hedge Apples themselves, 8 caterpillar species have been documented feeding on the tree. It's real value to wildlife however comes from the shelter the intertwining, spiny branches and leaves provide. Many animals use it for cover and it is a mainstay of hedgerows to this day, surviving as gnarled trees that now have gaps in between that allow many native plants to also grow. 

An Osage Orange

     I have some fond memories of this tree. It was (and still of course is) found along many of the fence rows which I frequented when I was young. My father when taking me hunting as a teen would have me serve some of the duties for the hunting dog we lacked. My brother and I would walk on either side of the hedgerows and flush the game while we hunted. As there were some thickets and the aforementioned spines to be reckoned with, my brother and I would try and find various ways to spook the game for all of us to hunt that would not involve getting into the thickets themselves. The Osage Oranges proved to be just what we needed. We would stop every few yards and load up our game vests with few. That way when we came across a particularly nasty thicket, we could just pull out some of the large fruits to launch into the hedges to flush things out rather than venture in ourselves. So this tree I associate with some of my early outdoor experiences, and I thank it for not just the habitat it provided, but also for saving me from getting poked by sticker bushes. 

Tuesday, November 3, 2015

Euonymus Leaf Notcher Moths

A male Euonymus Leaf Notcher Moth (Pryeria sinica), an exotic wasp mimic

     On October 29, 2015, one of our Arlington Regional Master Naturalists, Alison Sheahan, posted a photo and description of numerous moths that appeared in her yard on the master naturalist Google Group. This led to some of speculation as to what these were, since they looked fairly unusual with their clear wings and it was a strange time of year for moths to come out, especially in such large numbers (30-50 of them). They did not fit the description any of the moths I was aware of and so I decided to investigate a bit more.
     It then occurred to me that they might be an exotic species of moth I had read about in an invasive species alert a couple of years before. I asked if I could take a closer look at them and confirm my suspicions. A few days later I visited and was quite sure of what they were, but took some photos and collected some voucher specimens to send to some professional entomologists for confirmation. I then proceeded to ask our Extension Agent for assistance in getting in touch with their entomologist contact and to see what protocols needed to be followed in case they were the invasive pest in the original alert. The visit to our Extension Office provided a nice teachable moment since a Master Gardener class was taking place. This led to an opportunity to talk about invasive species, EDRR (Early Detection, Rapid Response), and how observant citizen scientists can help in detecting potential issues such as these moths could be. The entomologist eventually confirmed my suspicions.

Euonymus Leaf Notchers mating. The males have feathery antennae.

     Euonymus Leaf Notcher Moths were first discovered in North America in 2002 in a Fairfax, Virginia yard where they were causing great damage. The caterpillars were feeding in large numbers. and defoliating the Euonymus shrubs. It took a while before entomologists were able to figure out the exact species, an exotic moth Pryeria sinica. These sporadically showed up in several places in suburban Maryland over the next couple of years, leading Maryland to describe them as invasive species of concern.
     They can apparently survive our winters (they're originally Asian in origin), feed and reproduce in large numbers, are not eaten by many predators, and prefer to feed on various Euonymus species of shrubs, a group of plants used extensively in the landscape industry. They could therefore possibly cause great economic damage. Since we have native Euonymus (Strawberry Bush) and since they can also feed on the very widespread Bittersweet on occasion, their invasive potential is great. They seem to prefer Japanese Euonymus (Japanese Spindle-tree Euonymus japonica), which is what we found them on, but they appeared to also be on the Burning Bush Euonymus shrubs there as well.

Female Euonymus Leaf Notcher laying eggs and an egg mass with protective hairs (modified scales) from their own bodies

     There were several dozen flying that day (November 3) in the warm weather, mating and laying eggs. These moths appear to be wasp mimics, perhaps getting a measure of protection by looking like these stinging insects with their clear, scale-less wings. Euonymus plants have acyanogenic compounds in their leaves protecting them from getting eaten. I think the moths sequester these from when they fed on them as caterpillars and so are somewhat toxic as well. Their body "hairs" (modified scales called setae) likely are defensive as well. When they lay their eggs, they place hairs from their bodies on top to help protect them (see photo). Several moth species that have urticating, protective hairs also cover their eggs and cocoons with them.
     These are daytime flying moths, who come out in great numbers when few other moths or their predators are active. Since they have reduced mouth parts, I'm guessing they don't even feed as adults (it's the caterpillars who feed gregariously and notch the leaves giving them their names).
     Euonymus Leaf Notchers mate near or on their host plants. The females I think send out pheromones which attract the males and other females in large numbers. That is likely why the males have such feathery antennae, to detect the pheromones, and why they were so many together in one location. The females then lay egg masses (about 150 eggs at a time) near the top of pencil-thin Euonymus twigs where they will remain overwinter, hatching in late March or early April.

First instar caterpillars (newly hatched and not molted their first time yet) hang out communally, usually on the underside of the leaf.

     The caterpillars feed communally at first, leaving tell tale notch marks, or completely stripping the plant when in large numbers. They hide under the leaf and can wander far in search of food (as I discovered when a couple got underneath the screen I had them and wandered down the hall).

Multiple instars (molts) of caterpillars.

     Here's a short video of them:

     Some literature suggests just crushing the eggs or snipping the infected twigs off. That's what we did, but returned in the spring to see what we missed. There were hundreds, with us coming back a couple of times to try and eradicate them as their leaf damage gave them away. I'm raising a few to get photos of their complete life cycle, but well over a hundred have been killed, hoping we can contain or eliminate this threat before they spread.
     While their numbers were still low and since they are not strong fliers, it was a good time to get them, before they got established. But we missed some obviously and will have to keep our efforts up. That is one of the reasons for Early Detection and Rapid Response as a way to deal with new invasives. We may be able to prevent them from getting a good foothold, especially if we get the neighborhood and our local folks to keep an eye out for them. I've since heard that they've also just been discovered in Great Britain. Maybe someone will read this and be able to recognize this invasive moth if it moves into their community regardless of where they live.
     All this began when an informed master naturalist was curious about something new that she had never noticed in her yard before and asked her colleagues to help identify them. It just goes to show that keeping an eye out and taking interest in what is around you might lead to hopefully some timely actions.

Sunday, November 1, 2015

Shellbark Hickory

Shellbark Hickory leaves and nuts

     Shellbark Hickories (Carya laciniosa) are actually not native to our region, but have been widely planted. We found a very large one in of our parks. I had always wanted to try to eat them before and so decided to collect some. While all hickory nuts are edible, some are not supposed to be worth it. Thin shelled (hulled) nuts tend to be the least appetizing. Bitternut Hickories for example are named this for a reason, and Pignut Hickories are supposed to be only fit for pigs. Shellbark, much like Pecans, are thick hulled hickories on the other hand that have a reputation for being tasty.

Shellbark is the largest of our hickory nuts

     Shellbark Hickory nuts are also the largest of our hickory nuts. Unlike Mockernut Hickories, which also appear large, they do not "mock" you with small bits of meat. This is what I'd heard anyways, as well as how they can be tricky to crack just right to get at the meat but not crush them into tiny little pieces. 

Shellbark nuts and leaf

     So I collected a small bagful, feeling lucky to have beat the squirrels to them. Some had hulls still on them, others had already shed them. I cracked a few in my basement using a hammer, with various levels of success. After trying three of them, I was not impressed however. The meat did not look that appetizing and didn't taste very good at all. I wondered if I was getting the best nuts, specially after going through the trouble of trying to crack them just right. 
     It was then I recalled a way to test nuts for germination. You can float test nuts, sticking them in water. If they float, then they likely have air holes, insects or insect frass, and/or are rotten or have old meat. Those that sink have the best chance of being whole and best chance to germinate. It seemed that I could use the same test to figure out which nuts were worth cracking and which floated instead. Only about a third, after removing their thick hulls, I  was disappointed to find out, sank to the bottom and thus supposedly would be good to eat.

A float test, the ones that float are not likely to be good to eat or to germinate.

     But they were quite tasty indeed. My family enjoyed the small but worthwhile harvest. I still need practice opening them, but think I've saved some time by float testing them first. I also now will have to test all the other hickory nuts we have growing locally to see which other ones I can enjoy...

Shellbark Hickory nut meat

Shellbark Hickory in Fall color...