Adventure at my feet

I went for an afternoon walk at the Riverlands Migratory Bird Sanctuary yesterday. With binoculars and camera in tow, I looked at a pair of American Kestrels, a handful of Song Sparrows, and photographed a myriad of dried flowers. While walking through the vegetation, a flurry of movement at knee level caught my eye. I knelt down to find a Banded Argiope (Argiope trifasciata) wrapping up a grasshopper in her web.

Banded Argiope and prey

Mesmerized, I watched her for several minutes rotate around the grasshopper, leaving silk in her wake.

Spider wrapping grasshopper. Note the spider's spinnerets.

Spider silk is a protein produced in liquid form by special glands within the abdomen. The silk leaves the body through the spinnerets located at the end of the spider's abdomen. Once the silk leaves the body, it is transformed into dry fibers. Spiders can can manipulate the thickness, strength, and elasticity of their silk.

The Banded Argiope is a member of the Orb Weaver Family Araneidae and can be found throughout Missouri in tall grasslands and open areas with sparse brush.

You never know what you'll find during a walk in the park. I felt lucky to have this encounter with nature.

Preparing For Winter

With the arrival of Autumn Equinox last weekend, the hours of daylight will continue to shorten and the nights grow long until the Winter Solstice. On the surface, life seems to be slowing down on the prairie, but in reality, the plants and animals are busy preparing for the upcoming cold months.

Mantid Ootheca

Last week I found a Chinese Praying Mantis (Tenodera sinensis) ootheca, or egg case. A female mantis will choose a weed or other sturdy plant stem about 4 feet off the ground and begin the process of laying the ootheca and eggs. The eggs are usually arranged in rows near the plant stem, and on either side of the eggs, the female mantis lays a frothy, brown material filled with air. Initially this protective material is sticky and soft, but when it dries, this outer part of the case will be hard and water repellant. The female begins laying ootheca in August and can leave as many as 15 egg cases before she dies. Each ootheca can have up to 400 eggs. The eggs will survive the winter months within the ootheca and the nymphs hatch in late spring or early summer. These tiny mantids disperse on the wind and will molt up to 7 times before they reach adulthood.

There was one woolly bear caterpillar looking for food in the prairie. This fuzzy caterpillar is one of the many tiger moth species that belong in the Arctiidae family. These active caterpillars are covered in short, dense hairs and are always on the move searching for food and a safe place to overwinter.

Woolly Bear caterpillar

Monarch Butterfly on Goldenrod

Monarch migration has begun. Each fall, these butterflies fly to Mexico for the winter. The Monarchs that emerge in late summer to early fall are the ones that make the trip. This generation of Monarchs will not mate or lay eggs, rather they prepare for the long trip south. They need to store enough fat to travel and survive the winter months. This is an area of interest for scientists, as it is not known exactly how these butterflies store enough energy to survive such a difficult journey and live until spring. Amazingly, these same butterflies will migrate up north once spring arrives to reproduce.

There are a few hundred American Goldfinches feeding on the seed heads in the prairie and it appears that the young Goldfinches have mastered the art of foraging.

American Goldfinch

Illinois Bundleflower

The plants at the Ecology Center have gone to seed. This means that the plant uses its energy for creating seeds instead of growing. The seed head on this Illinois Bundleflower (Desmanthus illinoensis) is dried and ready to be dispersed. Illinois Bundleflower is an important food source for animals and botanists often use this plant when creating a restored prairie.

Ohio Buckeye

The seed pods from the Ohio Buckeye (Aesculus glabra) trees bordering the prairie have matured and are dropping to the ground. These seeds are covered by a rough, warty pod, and each capsule can house up to 3 seeds. Ohio Buckeyes prefer moist habitat, and can be found along streambanks and river bottoms. The seeds contain tannic acid and are poisonous to humans and livestock, but constitute a small percentage in the diets of squirrels and deer.

Stay tuned for next month's natural events!

Glossary

Cocoon: a silk web that encloses the pupae of many moths, but not butterflies. 

Forage: the act of searching for food.

Molt: the act of shedding skin. A monarch larva will molt its skin as it becomes too large for its former skin.

Nymph: Immature stage of an insect with simple metamorphosis

Ootheca: An ootheca (plural oothecae) is an egg mass produced by several different groups of insects, including Praying Mantids and Cockroaches. Oothecae contain many eggs with a protective outer covering.

Overwinter: to remain alive throughout the winter.

Pupate: to change from a larva (caterpillar) to a pupa (cocoon or chrysalis)

Fall Seeds

Autumn is a busy time at the Ecology Center with the staff collecting and cleaning seeds for planting in the spring. Before we discuss the process of collecting and cleaning, let's talk a little about seeds in general.

Annenberg Learner http://www.learner.org/courses/essential/life/

After a plant is fertilized, the egg cell divides many times to form the embryo, or the baby plant. The plant embryo forms a hard wall around itself and this is known as a seed coat. Within the seed is the endosperm, which provides food to the developing embryo. The cotyledons within the seed provide a similar function. These are the seed leaves and they also contain food for the developing plant. The seed coat houses the embryo and is able to withstand extreme temperatures, fire, snow and ice, abundant rainfall or dry spells. The seed coat also protects the embryo from abrasive material found in the soil, and passage through the digestive system of animal.


A newly formed seed may require days, weeks, months, or even years to fully mature and requires the correct soil temperature, moisture, humidity and length of daylight to germinate.

Although some plants drop seeds at their bases, most are dispersed through a variety of methods. Some seeds are designed to be lifted and carried on the wind; Maple trees, Milkweeds and Thistles take advantage of the wind.

Swamp Milkweed seeds are dispersed on the wind.

There are other seeds with barbs, bristles, tiny hooks and hairs that latch on to the fur of a passing animal or human clothing. Beggar's ticks (Bidens sp), Cockleburs, and Burdock (Arctium lappa) are a few examples of these sticky seeds.

Seeds attached to the author's pants.

Some animals, such as birds, eat seeds which are later distributed after the animal defecates. Some of these tasty seeds include Poison Ivy, Mulberries, Pokeweed and Japanese Honeysuckle.

Goldfinches love (and disperse) Purple Coneflower seeds

Seed cleaning may bring images to mind of scrubbing seeds with soap and water, but this is not the case. Seed cleaning is essentially separating the seeds from the chaff and spreading them out to dry. Ideally, colanders, sieves, window screens or other forms of metal screens are ideal for this step, but space and cost is something of an issue for us. We (or willing students) separate the seeds from the chaff on top of a white piece of paper or tray before moving the seed to another tray.

The newly separated seeds can be dried in paper or plastic bags (open for air circulation), dixie cups or spread out on small plates. The seeds need to be turned or stirred every few days to make sure they are dried evenly. Once dried, the seeds can be stored in a cool place (usually the refrigerator) out of direct sunlight until they are ready to be planted.

Glossary

Chaff: the outer material on a plant, such as the seed coat, dried flowers, leaves and other scaly material.

Germination: the process in which an inactive seed begins to sprout and grow into a seedling under the right conditions.

 

The Late Bloomers

For the first time last week, I began to hear the familiar begging calls of young American Goldfinches. I peeked outside and sure enough, there were 3 hatch year Goldfinches on my patio hopping around, pecking at leaves and exploring the covered BBQ pit. One of the goldfinches hopped under the BBQ pit, another one perched on a flower pot, and the last goldfinch started to fly towards the BBQ pit. I think he was trying to reach the top of the pit, but his takeoff was too close, so he settled for the side instead.

A hatch year Goldfinch looks very different from his or her parents. In that same turn, male and female goldfinches also look different from each other. This difference in the feather colors between males and females is known as sexual dimorphism. During the summer, male goldfinches are bright yellow with a black head and wings. The females are a muted yellow, and lack the black head.

The young goldfinches were in various stages of learning to feed themselves. One little goldfinch begged his sibling for food...while on the bird feeder. But there was another young goldfinch that was beginning to master the art of foraging. This little one was plucking seeds off my Purple Coneflowers (Echinacea purepurea) in the backyard.

American Goldfinches nest later than other songbirds. Most birds breed late April through mid June but the goldfinches begin breeding in late June through July. These birds breed when milkweed, thistle and other plants have produced their fibrous seeds. The female builds the nest, usually in a shrub or sapling in a fairly open setting rather than within a forest. The nest is often built high in a shrub, where two or three vertical branches join; usually shaded by leaves of clusters of needles from above, but often open and visible from below. The nest is an open cup of plant fibers and rootlets and the interior is lined with the fluffy material surrounding the seed from thistle and other plants. The nest is so tightly woven that it can hold water. 

Goldfinches are seed eaters, even during the breeding season. While most seed eaters, such as Sparrows, switch to an insect diet during the summer months, the goldfinches continue their seed eating diet and feed their young the seeds from trees, flowers, and shrubs.

 

You can find American Golfinches in parks, weedy fields, pastures, grasslands and in fields containing mature sunflowers. They will also eat from bird feeders that offer sunflower and thistle.

You may think that the bright yellow colors of the American Goldfinch really stand out - and indeed they do in a backyard while perched on a bird feeder. But out in a field of flowers, they are well camouflaged. Can you find the Goldfinch in this picture?

Be on the lookout for our pretty yellow feathered friends. If you are around a small field of, or even a cluster of dried flowers, the Goldfinches are sure to be nearby. 

Glossary

Hatch Year: A bird that has hatched during the spring or summer. A young bird will be considered a hatch year bird until January 1st, when all are then considered adult birds.

Camouflage: The colors and markings of an animal or bird that allow it to blend in with its surroundings so as not to be detected by predators.