December 2020 – Discover-Nature

Conifers

Conifers are one member of a group of plants known as gymnosperms, meaning ‘naked seeds’, a reference to the seed not being enclosed in an ovary or fruit. These plants do not flower, but have both male and female cones. The male cones carry pollen, which is dispersed by the wind. The female cones that come in contact with the blowing pollen will take some into the ova and produce seeds in the cone. Cones are green as they grow, turning brown as the seeds mature. When cones open, seeds are dispersed by falling to the ground or being picked up and moved by animals. In some conifer species, cones will not open until certain environmental conditions are met, namely the presence of fire. These species have serotinous cones, ones that only open when exposed to high heat. Fire also kills other plants that compete with conifers for resources such as sunlight and water, and it releases minerals from burned plants into the soil providing nutrients for new conifer seedlings.

White Spruce, *Picea glauca*, by Northern Forest Atlas Foundation

Most conifers are evergreen, although a few are deciduous. Deciduous trees lose their leaves all at the same time, when temperatures start to drop in autumn. Evergreens also lose their needles, a few at a time throughout the year, and they are quickly replaced by new growth so the tree is never bare. Evergreen needles are thin leaves found on several types of conifer including fir, spruce, and pine. Other types of conifers like juniper, cypress and cedar, have soft, scale-like needles. An examination of the needles is the best way to identify a conifer species. Whether they are stiff and sharp, or flexible and soft; bunched in groups or growing singly; and the number of needles that are in each bundle will help you to identify a specific tree species.

Austrian Pine, *Pinus nigra*, needles in sheathed pairs, by DonArnold

Climate conditions, especially temperature and precipitation, greatly influence the tree species found in any one area. Colder temperatures reduce the ability of plants to function. Deciduous plants handle this change by entering a state of dormancy until warmer temperatures arrive in spring. Precipitation in northern Illinois is generally well distributed throughout the year, although in winter, it falls as snow. Combined with a frozen soil layer, this water is not available for ready use by any plant species until the spring thaw. Evergreen species are well equipped to handle these conditions. Needles have a waxy, outer covering, while roots and stems are filled with resin, a chemical that acts as antifreeze. The general shape of the tree, with branches sloping down and out, keeps snow from accumulating and freezing on the foliage. The plants can survive very cold temperatures without damage and are able to start photosynthesizing food as soon as liquid water is available in spring. This gives evergreen species a jump on shorter growing seasons in cooler northern climates.

Austrian Pine, *Pinus nigra*, unopened seed cone, by DonArnold

Conifers in this area are used extensively by birds, mammals and insects for food and shelter. They make good habitat, providing protection from wind, rain and flying predators. A wide variety of insects call conifers home including spider mites, aphids, bark beetles and various caterpillars. Many of these insect species provide food for woodpeckers and nuthatches. Squirrel nests are well screened from wind and precipitation by evergreen boughs. During the day, many bird species like to browse among the ground litter of pine needles and fallen food. And later in the evening, that same activity is taken up by several mammals prowling the night time.

Hairy Woodpecker searching for insects on Austrian Pine, by DonArnold

There are about 700 conifer species found world-wide, and they can be found in backyards, city parks and nature areas all over DuPage County. They are most abundant in cooler climates and are important timber trees. All are softwoods, a versatile building material for mouldings, windows, flooring, paneling and plywood. They provide great backyard habitat in our area, and serve as an important natural resource for many over-wintering species in DuPage County.

Irruptions

An irruption is a birding term referring to an unexpectedly large increase in the population of a bird species into an area where they are not normally seen. Irruptions are caused by a disturbance in the natural environment of the species, many times due to a food shortage. Depending on the root cause of the disturbance, more than one bird species may be affected.

Pine Siskin, by Karen Lebing, Pocosin Lakes NWR

Mast refers to the fruit of woody plants, such as acorns, nuts and berries. In some years, plants produce larger than normal quantities of mast, and in other years the production amount is meager. Many species depend on this mast as their main food source. One theory about why the amount of seed varies suggests that in years of abundant production, the number of seeds overwhelms the number of seed-eaters, and the plants have a greater chance of successful reproduction. In years when very little seed is produced, lack of food thins out some seed-eating species and forces others to move. Many bird species rely on mast as their main food source, and when the food becomes scarce, these species move farther afield, irrupting into new locations.

In 2020, we have already experienced several irruptions across the North American continent. Cone-bearing trees in boreal forests in Canada produced small seed crops this year. There is not nearly enough mast to feed the populations of birds that spend the winter in these areas. Most of the affected species will head south into the United States, fanning out over broad areas in search of other food. Nuts, seeds and berries from other trees may replace what has been lost, but many species will be opportunistic and eat from backyard feeders when possible.

Pine Siskin, Spinus pinus, normally move into southern Canada and the northern half of the U.S. in winter. Overwhelming numbers have been reported by observation stations, especially along the east coast, and birds have been spotted as far south as the Gulf of Mexico. Their normal winter range includes northern Illinois, but not in the high numbers that we are currently observing. They are about the same size as American Goldfinch, with dark and light brown streaking covering their entire body and distinctive bright yellow wing and tail edges. Pine siskins prefer evergreen forests, but will eagerly feed on thistle seeds from feeders.

Red-breasted Nuthatch by Becky Matsubara

The Red-breasted Nuthatch, Sitta canadensis, is another species seen here in smaller numbers in winter, but also heavily affected by the reduced amount of food. This species is irrupting both north and south, with some populations heading north into Alaska, and many more individuals heading south into all parts of the United States. As with the Pine Siskin, higher numbers of birds are being reported in our area for the second winter in a row. These birds have blue-gray backs with rust-colored breasts and a black-capped head with a bright white stripe above the eye. One of our smallest birds, they have a very short tail and short, broad wings on a plump body. They prefer coniferous woods and mountain areas, but in winter, they can be seen on backyard feeders offering black-oil sunflowers seeds, suet, and peanuts.

Blue Jay, Cyanocitta cristata, annually migrates by the thousands through the Great Lakes and along the east coast heading for winter habitat in the southern U.S. Smaller populations may remain along the migration route, but this year, we are seeing greater numbers in many places. One of our largest feeder birds, they sport a large crested head and a broad, rounded tail. Blue Jays have a white or light gray belly and black and white markings against a bright blue back and head. Their preferred habitat is along forest edges, especially where there is an abundance of beechnut, hazelnut and acorns. In backyards, they are most often found on tray feeders offering peanuts, sunflower seeds and suet.

Bohemian Waxwing, Bombycilla garrulus, may not be as familiar in our urban and suburban areas, but it is also experiencing an irruptive year. These medium-sized birds are plump, with a thick neck and a short, squared off tail. They are grayish brown overall with a striking black eye mask shaded along the edges in dusky orange. The underside of the tail is rusty, and the tip is bright yellow. Secondary wings on adults have bright red wing tips. These birds move frequently in search of food sources, making them unpredictable to find; and we are at the south end of their typical winter range. Keep an eye out for flocks as they are being pushed farther afield this year in search of food.

Irruptions can be an exciting event for bird watchers who are able to observe species that migrate outside of their normal range when conditions necessitate such movements. An irruption may be difficult to identify, but if you observe larger than normal groups of any species, especially in late autumn, that is a clue that there may be an irruption in progress. Keep abreast of current bird migration monitoring at sites such as the Finch Research Network or Bird Cast.

My Nature Bookshelf

It is starting to feel like the holidays have arrived, a time for snow and lights, cross-country skiing in the woods followed by hot cocoa inside, a quiet evening with family and presents, presents, presents! My wife and I are both avid readers, so the hunt is on for each of us to find that book that will be relished but that has not yet even been contemplated. I love to browse through bookstores, especially those with both new and used volumes just waiting for me to find them. Here are some of my favorites.

City Creatures: Animal Encounters in the Chicago Wilderness, edited by Gavin Van Horn and Dave Aftandilian is full of essays and poems, accompanied by illustrations and photographs, that introduce you to a variety of species that live among us in the urban environments of northeastern Illinois. The book is divided into six sections; each introduces us to a different place that includes animal encounters. Gavin Van Horn is also the creative director and executive editor for the Center for Humans and Nature, and you can find several of his pieces framing new perceptions of the environment on their website.

Winter World: The Ingenuity of Animal Survival, and its companion volume, Summer World: A Season of Bounty, both by Bernd Heinrich are in-depth explorations of what it takes for different species to survive the environmental conditions present at different times of the year. Heinrich looks at many of the adaptations that allow animals to find appropriate shelter, warmth, food and mates in extreme conditions.

Fire and Ice by Jonathan Mingle is an investigative piece written over several years of traveling to the Himalayan region of Zanskar in northwest India. In recent years, this region has been drastically changed by drought due to disappearing glaciers. Mingle ties this in with the problems being generated by black carbon, the unburned particulate matter from fire of all types. He tells a wonderful tale of the people and their family stories, as well as how black carbon is making a huge impact on their region and the entire world.

Another section of my shelves includes books that provide a wonderful assortment of activities that can involve everything from individual investigations to gathering data for citizen science projects.

The Laws Guide to Nature Drawing and Journaling by John Muir Laws is a detailed presentation on how to make simple to complex drawings for anyone who enjoys the hobby of journaling. It includes instructions on making simple line drawings, the use of colored pencils, and working with watercolors. There are numerous examples on what to journal, gathering your thoughts in the written word and transferring your observations to pictures on a page. A fun and entertaining treatment of nature journaling.

The Amateur Naturalist by Gerald Durrell, published in 1983, or by Nick Baker, published in 2005, are both excellent books with tips and activities on observing nature. They provide information about different habitats and species, how to make observations of each, what data to record, activities that will make your time fun and rewarding, and suggestions on how your data may be used by yourself and others. The books identify tools to collect and use to make your ventures into nature fun learning experiences.

A companion volume, How To Shoot An Amateur Naturalist by Gerald Durrell, tells us how he made the television series “The Amateur Naturalist,” based on the book above. It is a humorous and fun story of film making, adventure and travel concentrating on learning natural history using a variety of the techniques and activities detailed in his book.

Another fun book is The Big Year by Mark Obmascik, also made into a motion picture starring Jack Black, Steve Martin and Owen Wilson. The book takes us on a wild romp through nature areas, backyards and wild places with the goal of counting as many bird species as possible in one calendar year. Documenting the journeys of three bird watchers taking a year out of their lives to compete for the honor of counting the most birds in one year in the U.S., this volume is a humorous and insightful story of just how passion can turn a hobby into an obsession.

The Lost Art of Reading Nature’s Signs by Tristan Gooley provides thoughtful insight on how to enhance your nature walks. Everywhere we go, there are hundreds of things to see in nature. This volume can help you learn what to look for that you may have missed in past walks. The book provides dozens of ideas about what to look at, how to discern more detail, and what questions to consider as you discover things along your way. A fun way to learn about learning as you enjoy each nature walk you take.

These books can provide a perfect starting place for a new year of activity and learning while having fun. Find one for yourself or consider a gift book for a friend who loves nature. If you have books that you have found to be insightful and interesting, or have started you on a new journey, consider posting them in the comments section for this blog. Have fun browsing!

Sun-Earth Relations

Thanksgiving has come and gone, and we are moving into late autumn and starting to think about winter snows. As we enjoy autumn activities, the earth is moving ever closer to the sun. In January, the earth will be at its closest approach to the sun than any other time of the year. So, why are we in the deep freeze at that time?

The earth’s axis is a straight line passing through both the north pole and the south pole. In relation to the sun, the axis is tilted 23.5˚ to one side. Referring to our diagram above, called “Earth Axis”, the subsolar point is where the sun’s rays directly hit the earth at right angles. The northern hemisphere is tilted away from the sun during winter in our area, when the light and warmth of the sun is striking the earth at an oblique angle, compared to the much more direct sunlight striking the earth in the southern hemisphere’s summer.

The tilt of the axis changes slightly every year causing a wobbling movement. The wobble is called axial precession and can be visualized by watching a spinning top as it moves across a floor, not quite perfectly smooth. As the top moves in circles, so does the wobble of the earth, taking about 26,000 years to return to the same orientation. Earth’s spin drifts slowly east and west, but never very far. The farthest movement observed from the center of the axial spin, since recording began in 130 B.C., has been 37 feet. This will not affect daily life but does affect GPS and satellite observations.

There are many theories about what causes axial precession, but data from the last five to seven years shows a strong possibility that movement of water around the world is responsible. Changes in the amount of water and ice can be counted as changes in mass and weight. These types of changes near the poles have no significant effect on the earth’s spin, but where these changes occur in the middle latitudes, around 45˚, greatly impacts the stability of the spin. Losses of water in the Europe-Asia-India areas has created an imbalance in mass and weight sufficient to alter earth’s spin and account for some of the recent wobble movements. There are strong correlations with other water movements back through the last 2,150 years of history.

As the earth moves through a one year orbit around the sun, the tilt of earth’s axis does not change. As shown in the diagram labeled “Earth Orbit”, this means that for a quarter of the year, the northern hemisphere is leaning towards the sun. In mid-June, the summer solstice occurs when earth’s tilt and orbit brings the northern hemisphere closest to the sun, and we experience the longest daylight period. The winter solstice, occurring in mid-December, is when the southern hemisphere is closest to the sun, and the northern hemisphere experiences the shortest day of the year. The two in-between periods, vernal (spring) and autumnal (fall) equinox are when the sun’s orbital path crosses the equator, and day and night hours are about equal.

If you would like to learn more about the seasons, consider the following resource links: National Geographic Earth-Sun Relationships; SUNY Earth-Sun Relation; U of I Extension Ecosystems; and U of I Global Temperature Learning.