Saturday, March 28, 2009

Spring Peepers

First frog program of the year last night; I was afraid it was going to be too chilly for much frog activity, but we were pleasantly surprised to find the Reflecting Pond absolutely rockin' with Spring Peepers (Pseudacris crucifer) in full chorus. These tiny little frogs are no bigger than your thumb, and can be identified by the vaguely cross-like marking on their backs, which is where the scientific name "crucifer" comes from. They may be tiny, but these little frogs pack some mighty vocal power. A few minutes spent in the middle of an army of chorus frogs and your ears actually ring. ("Army" is the term for a group of frogs, like "flock" is to birds). Only the males call, trying to attract a female. Calling is the most energy expensive activity a frog can do, so the females know that males able to call long and loud are likely to be healthy and good potential fathers for their eggs, genetically speaking, anyway. Once the eggs are laid, both male and female Spring Peepers head back to the forest, and the tadpoles grow up with no parental care needed.
Here's a video clip of a male Spring Peeper calling, with another nearby, probably a female. The male really puts his whole body into the effort of calling - hopefully the female peeper was impressed!

And another short clip of a peeper calling - this one looked like he waved at me!

Peepers were the only frog we heard calling, but I did spot one very sleepy Bullfrog (Rana catesbeiana) poking her head up. Spring Peepers spend the winter in the forest, burrowed underground. They actually have an anti-freeze-like substance in their bodies that prevents them from suffering damage from sub-freezing temperatures. Bullfrogs, on the other hand, spend the winter under the ice of the pond, hibernating in the leaves and muck at the bottom. Because of the cold temperatures their energy needs are very low, and they can take in enough oxygen through their skin to sustain them.

I could tell this Bullfrog was a girl because her tympanum, or ear, the little circle just beneath her eye, is smaller than the eye. On a male Bullfrog the tympanum is larger than the eye. This doesn't work for Spring Peepers, but you can still tell the males apart by the yellowish or dark brown deflated vocal sac on their throats, while females have white throats.

Thursday, March 26, 2009

Hemlock and Spruce and Pine, oh my!

There are several coniferous tree species found in Eagle Creek Park; for instance, the long magestic row of tall Norway Spruce (Picea abies) trees with their graceful upward arching branches along the main road by the Ornithology Center. They were originally planted by the Lilly family, and there are several around the EDC as well. As the name suggests, Norway Spruce is native to Europe. There is a White Spruce, Picea glauca, which is native to Indiana, but I've not found any growing in the park.Spruce needles are very stiff, and quite sharp. Folks who celebrate Christmas with a live spruce tree usually have a few uncomfortable prickly moments setting them up!The cones of the Norway Spruce have densely packed scales, and are 6+ inches long (cones of White Spruce are much smaller - less than 3 inches). Squirrels like to strip them of their scales and eat the seeds, leaving the central stem of the cone behind.
If Norway Spruce has the biggest cones, the Eastern Hemlock (Tsuga canadensis) has the tiniest - these little doobers are only about an inch long.
Eastern Hemlock has flat, rounded needles, soft and flexible, rather than stiff and sharp, with two whitish lines on the underside. This is not the same hemlock that killed Socrates (the poison he drank was made from an herbaceous plant that looks a bit like parsley - Poison Hemlock, Conium maculatum) so don't worry about touching and handling Eastern Hemlock, it won't bite! In fact, pioneers often made tea from the needles, which, like most conifer needles, are high in vitamin C. Deer also find the Hemlock needles tasty; the trees in the park are all browsed as high as a white-tailed deer can reach.
Eastern Hemlock prefers cool and humid growing conditions, and unlike most other conifers it can grow in the shade. Most of the trees in the park were probably planted, but they grow naturally in ravines in southern Indiana. These cool, humid microclimates became refuges for hemlock trees when the glaciers retreated long ago, and Indiana became too warm and dry for them to survive in more upland forest.
Next we have the cones of the Eastern White Pine (Pinus strobus) - similar in size to Norway Spruce, but the scales are much less densely packed, and they are often adorned with white bits of sap on the ends. White Pine is native to Indiana, but the original range was only in a few small pockets - the trees in the park were probably planted. Check out the "Native Trees of Indiana Riverwalk" for some excellent range maps of Indiana trees:
White Pine holds the record of being the tallest tree in eastern North America; pre-colonial trees were reported to reach over 200 ft tall, and the current record holder is just over 180 ft. The tall, sturdy trunks of the White Pine were in great demand during colonial times to be turned into masts for the ships of the British Royal Navy.
There is a large White Pine growing near the deck at the Ornithology Center, and one at the edge of the Grasshopper Field by the EDC.
Needles of the White Pine are long and slender, and grow in clusters of five. Quite conveniently, the word "white" has five letters, making this fact a little easier to remember. The needles look sharp, but they are actually quite soft and flexible.
The other common pine tree in the park is the Virginia Pine (Pinus virginiana). Its needles grow in clusters of two, and the needles are slightly twisted or spiraled. There are several stands of Virginia Pine planted in the park - you can find them growing along both the Pin Oak Loop and the Cabin Loop Trail by the EDC. Virginia Pine is native to Indiana, but only occurred naturally in the south, along the Ohio River.
Most of the Virginia Pine trees in the park look rather worse for wear. It is hard to even tell they are pines in most cases, unless you look to the very top and see the needles. Virginia Pine is shade intolerant, and has a very short lifespan - only 60 to 90 years - and that is about how long ago they were planted. Norway Spruce can live a little longer, 100-200 years, and White Pine and Hemlock can reach ages of 300 to 400+.
The cones of Virginia Pine are medium in length, around 3 or 4 inches, and have a sharp thorny spur on the tip of each scale.

Ohio Buckeye

The first tree to leaf out in the park is the Ohio Buckeye, Aesculus glabra. Most of them are quite small - there are clusters of young trees at the end of the driveway coming out of the Ornithology Center, another patch just before the sharp curve at Fisherman's Cove, and near the end of the Cabin Loop trail by the EDC. I only know of one big tree in the park, although there are probably others scattered around.
The European version of the Buckeye is known as the Horse Chestnut, Aesculus hippocastanum, and is sometimes planted as a landscape tree. Despite the name, this is not the chestnut of "roasting on an open fire" fame - the nuts produced by both of these trees are actually toxic to humans, although deer and a few other animals can eat them without harm. Edible chestnuts come from the American Chestnut, Castanea dentata, a member of the beech family, which sadly has disappeared from most of our forests due to an introduced fungal disease.
Although it may look like I'm holding five leaves here, in actuality there is only one compound leaf in the picture, a single leaf composed of five leaflets. Buckeye leaves are also palmate - shaped like a hand with all of the leaflets connecting at the center. Some compound leaves, like those of the walnut, are pinnate - shaped like a fern, with the leaflets along a central stem. The new leaves are dark red, but they'll turn green as they get larger.
Here's a photo of a Buckeye from earlier in the year, which shows how the buds/leaves are arranged in an opposite pattern on the twig, rather than alternate. Opposite leaf and bud arrangement is an important clue when it comes to tree ID, as there are only a few tree groups that have opposite leaves: Maple, Ash, Dogwood, Horse Chestnut, and Buckeye. MAD Horse Bucks is an easy way to remember the opposite-leaved tree groups. I've also seen MAD Cap Horse - the "Cap" stands for the family Caprifoliaceae, which includes shrubs like honeysuckle, viburnum, and elderberry, all opposite-leaved.

Tuesday, March 24, 2009

Wildflowers - the leafy preview!

Over the last week, the forest floor has become a carpet of wildflower leaves, poised to burst into bloom. Here's a preview of coming attractions!

Spring Beauty
Cut-leaf Toothwort
Deer Tongue / Trout Lily
Toad Trillium
Dutchman's Breeches
Mayapple unfurling
Like a patio umbrella


Similar to Bloodroot, Hepatica blooms early and briefly - you have to stay alert to catch it in the spring! On first glance Hepatica can look a little like Bloodroot, but the leaves are very different. These flowers were growing along the staircase up to the cabin. Sometimes the leaves are green, but along the staircase they were dark red - can you spot their three-lobed shapes among the dead tree leaves? The Hepatica was also blooming all along the bank overlooking the little creek in the ravine, at the bottom of the wooden staircase on the Cabin Loop Trail.
Hepatica can be white or lavender in color:
My favorite thing about Hepatica though? It's fuzzy! The stems and new buds are covered with white fuzzy hairs, probably as insulation from the cold temperatures of early spring.

Sunday, March 22, 2009


In the space of a day it seemed like, the Bloodroot burst from the ground at my house! I have not found any yet at the park, but I haven't really had a chance to look in too many areas. You have to enjoy the bloodroot flowers while they're up - they don't bloom for long, although the leaves last well in to spring. The leaves have deep notches around the edges, and in my opinion are just as interesting as the flowers. Bloodroot is named for the reddish sap that oozes from the roots. It was used historically for medicinal purposes, but the sap can cause severe skin lesions and can even be lethal if too much is taken internally. The seeds of bloodroot are adapted to be spread by ants. The seeds have a fleshy area called an elaiosome. The sole purpose of the elaiosome is to entice ants into carrying the seed back to their nest, where they eat the fleshy treat, but leave the rest of the seed undamaged, and now buried in a nice fertilized ant mound, ready to grow. How awesome is that! The process of seeds being spread by ants is known as myrmecochory.

Tuesday, March 17, 2009

Carrion Beetles - Gross Stuff Warning!

White-tailed Deer love to hang out right in front of the EDC. They seem to be shedding their winter coats - we found a few clumps of deer fur along the trail!A park volunteer brought me a partial deer skeleton that he found on the other side of the reservoir. Since it still had some meat and fur on it and is a bit smelly, I put it out alongside the trail for the scavengers and decomposers to finish cleaning. The skeleton has only been there a week and already it has been discovered by carrion beetles (family Silphidae), who were working away industriously at cleaning up the remaining dried up bits of flesh from the bones. Here's a video of some of the beetles working away. There appear to be two types of carrion beetle here - all black ones, and some with orange on their heads, almost like lightening bugs. I find them fascinating, but if the thought of beetles scuttling about and munching on a dead deer grosses you out, you may not want to watch this one. Just imagine how gross it would be if they DIDN'T eat the deer though - yuck!

A Winter's Butterfly

While walking along this Monday we were greeted by the sight of a dark-colored butterfly flitting through the forest - in March! Most butterflies and moths overwinter in the chrysalis or cocoon stage. A few, such as the black-and-orange woolly bear, hibernate as caterpillars, but the Mourning Cloak overwinters as an adult butterfly, and is thus the first to emerge in the spring. Occasionally folks who bring in firewood in the wintertime are surprised when a hibernating butterfly wakes up with the indoor warmth and starts flying around their house! Mourning Cloak adults feed on tree sap more than flower nectar, while the caterpillars feed on willow species. (The photo is from wikipedia - the butterfly we saw didn't hold still long enough for me to get a picture!)

Honeysuckle to Honey Locust

Ah, the first green leaves of spring...unfortunately, they belong to the invasive exotic, the bush honeysuckle. Bush honeysuckles are some of the most pervasive and difficult to eradicate invasive species in Indiana. They create dense shade that prevents native wildflowers and shrubs from growing; some species even release growth-inhibiting chemicals into the soil. The Indiana Native Plant and Wildflower Society (INPAWS) has a very informative flier that lists the ten most damaging invasive plant species in Indiana, including the bush honeysuckle and the Japanese honeysuckle vine:
In addition to the early appearance of leaves, bush honeysuckle can be identified by the opposite branching pattern of the twigs and leaves (most of our native shrubs are alternate).
When walking through the forest sometimes you run across a tree with a strange lump, almost like a tumor. These woody outgrowths are known as burls (also known as burrs). No one is entirely certain what causes them, but it is believed that most are triggered when the tree undergoes some sort of stress - from certain types of mold or insect infestations, physical damage, and possibly genetic susceptibility. Some burls can grow quite large, and the wood is prized by artists and furniture makers for the unique and beautiful woodgrain patterns. The bark of the Cork Elm (Ulmus thomasii) is squishy, and indeed, very corklike! The bark grows in layers, typical of most elm bark. According to wikipedia, the Cork Elm is susceptible to Dutch Elm Disease, which may explain why we only seem to find a few small trees in the park.
If you're a tree hugger by nature, you might want to consider giving this tree a friendly, careful pat instead! These impressive thorny growths are found on the Honey Locust tree (Gleditsia triacanthos), making it a very easy tree to identify, even in the winter. The "honey" the tree is named for comes from the sweet pulp of the long bean pods the tree produces in fall, used for food and even fermented into beer by Native Americans. The pulp of the Black Locust tree bean pod is toxic, so be sure you have the right tree if you ever decide to taste it. Thornless varieties of the Honey Locust are often sold in plant nurseries for landscaping.

Monday, March 16, 2009

Semi-tame Wildflowers

Down the sides of the ravine between the EDC and the Peace Learning Center there are some not-so-wild wildflowers growing: the leaves of the familiar daffodil are poking up from the forest floor in good-sized clumps. Most of them were probably planted by the Lilly family (who built what is now the Peace Learning Center as a summer residence), and we have been told they are of an older variety not commonly seen today. Daffodils are are originally from Europe, Asia, and North Africa, and are not native to North America. Although they are an exotic species, daffodils are not considered to be an invasive species; they spread slowly, and do not outcompete the native wildflowers. Daffodils are also sometimes called jonquils or narcissus, and in the southern US they are sometimes referred to as buttercups, although "buttercup" can refer to several other species of flower as well.

Another non-native spring flower found in Eagle Creek Park, the bright electric-blue flowers of Scilla are easy to spot. The name is pronounced "Sill-uh," and it is also known as Siberian Squill. There seems to be quite a bit of variation in the common and even the scientific names - I've seen it called Scilia, Scilla siberica, and Scilla sibirica. Scilla is a member of the lily family, and, as the name suggests, came originally from Siberia. I wasn't able to find any information on whether they are considered invasive or not in Indiana, but I hope not - they're awfully cute! We found this one growing at the beginning of the Pin Oak trail in front of the EDC.

And yet another non-native early spring flower probably planted by the Lilly family: Snowdrops, also introduced from Europe. These hardy little white flowers are usually among the first flowers to bloom, sometimes even in February. They've spread to create large patches down the sides of the ravines just north of the Peace Learning Center.

Here's a close up of a snow drop bloom - when hanging down it is hard to see their beautiful green centers. This one had some tiny beetles living inside, and while I was watching, several bees and flies visited the other flowers to gather pollen and nectar.

The leaves of Virginia Bluebells were poking out of the ground near the same area as the Snowdrops. Some of them had a purplish cast, making them look like little cabbages. This one had some flower buds forming already - usually they don't bloom until later. Virginia Bluebell is actually a native wildflower to Indiana.

Wednesday, March 11, 2009

Monday Volunteer Walk March 9th Part 2

The leaves of the False Rue Anemone were poking out through the dead leaves on Monday - another sign of spring-to-come. Later they will create carpets of delicate white wildflowers. There is also a True Rue Anemone - not sure why this is considered to be the false one!

More early wildflower leaves peeking up through the forest floor - this three-lobed leaf is much thicker and sturdier than the fragile False Rue Anemone leaves and belongs to Hepatica. The leaf was thought to resemble the three lobes of the human liver, and thus, logically, the plant must be good for treating liver ailments! Hepatica is the Latin word for "liver," and another name for Hepatica is "Liver-leaf." This belief, that the appearance of a plant indicates its medicinal purpose, is known as the "Doctrine of Signatures."
We found the Hepatica growing along the stairs up the hillside leading to the old cabin. Not a pioneer cabin, although it is fun to pretend! This would be far too large and difficult to heat for a pioneer family. The cabin was built in the 1950's by the CEO of Indianapolis power and light (I still need to double-check the date, so don't quote me on that), and is constructed of old telephone poles!

Driving through the park in winter, it is easy to notice all of the young American Beech Trees (Fagus grandifolia) in the understory of the forest. Older beech trees drop their leaves in late fall, like most deciduous trees, but the younger beeches hang on to theirs for some reason. It is fun to hear the dry papery leaves rattle in the breeze, and they often are bent up in the direction of the prevailing winds by the end of winter. Young beech trees are able to grow in the shade, unlike the oaks and hickories, and so beeches, along with maples, are part of the mature Climax Forest of Indiana.
The long pointy leaf buds of the beech tree were formed last fall, and have been waiting patiently all winter for warm weather to come. They look quite dangerous and sharp, but don't worry - they're harmless (although I wouldn't recommend getting your eyes within poking range - look closely, but not TOO closely). You'll see a lot of my fingers in these close-up twig and bud shots - that was the only way to convince my camera to focus!

Another fun leaf bud - this one reminds me of a tiny fuzzy knife blade and is found at the tip of the Paw Paw, or Indiana Banana. I like to pet them - they are so silky soft! The round fuzzy bud further down the stem will open up in to a dark maroon, bell-shaped flower.

The strange and interesting twigs of the Winged Euonymus (Euonymus alatus), also known as burningbush for the bright red color of the leaves in the fall. The corky ridges are thought to be an adaptation to discourage browsing by deer.
Unfortunately, winged Euonymus (pronounced YOU-WAN-IH-MUS) is considered an exotic invasive species in our woodlands, brought over from northeastern Asia as an ornamental in the 1860's. When planted as a landscape plant away from forests it is usually not a problem, and there are several cultivated varieties that are less invasive and provide beautiful bright red fall color, but recent studies have shown that native trees and bushes are much more valuable to wildlife, especially birds, than the exotic species commonly used for landscaping. The key is in the BUGS!
Native species are host to a whole community of caterpillars, beetles, and other invertebrates that are a vital source of FOOD for songbirds. Trees and bushes brought in from other parts of the world are missing the network of insects that have adapted to living with them in their home country. Although they provide some shelter, and some species may produce berries or nectar, their main value as an insect smorgasbord is missing.
Planting native trees and bushes is a much better choice for wildlife. It is a gargantuan task, but we also attempt to control exotic invasive shrubs and bushes in our forests, so that native shrubs have a chance to grow. There are native varieties of Euonymus, although they don't have the nifty wings on the twigs. We'll have to see if we can find some growing this year.
For some excellent reading on the value and importance of native plants to our declining bird populations, check out the book "Bringing Nature Home" by Douglas W. Tallamy: