DuPont Environmental Education Center

By Guest Blogger: Martha Corrozi Narvaez

Associate Policy Scientist, Water Resources Agency, Institute for Public Administration, University of Delaware

On an unseasonably warm Sunday in February I walked hand-in-hand with my 4-year old son along Wilmington’s riverwalk that parallels the magnificent Christina River. As we walked we passed by couples, families, runners, and people of all types with the musings of ice skaters in the background. My son and I talked about the ducks swimming by, the swift current carrying sticks and other debris and the “mean people” that littered their bottles and trash in the river. I couldn’t help but think that just a few years ago I would not have been able to share this experience with him. I am fortunate to share such an experience with him and I also feel fortunate that I understand the complexity and state of this river.

Christina River on a warm winter day.

Christina River on a warm winter day.

It is easy to see that the Christina River has undergone an urban renaissance resulting in the Chase Center, Tubman-Garrett Riverfront Park, Christina Riverwalk, a variety of restaurants, high-rise residential buildings, the Blue Rocks stadium, and the DuPont Environmental Education Center’s wildlife refuge. This growth is spurred by people’s desire to be near the water and the aesthetic qualities it provides, yet beyond this beauty there is a complex, natural system at work.

The headwaters of the Christina River lie within the state of Maryland and enter Delaware west of Newark. The White Clay, Red Clay, and Brandywine creeks are tributaries of the Christina River. The Christina River is freshwater yet tidal from just south of the town of Christiana to its confluence with the Delaware River at Wilmington. Extensive tidal freshwater wetlands, including Churchmans Marsh, exist along the lower Christina. The majority of the Christina River watershed is located in New Castle County (DE). The Christina River is a mostly urbanized watershed with over 50% of the land cover developed. The watershed is the site of the Port of Wilmington, an important shipping link, and one of the largest importers of orange juice, Chilean grapes, bananas, and automobiles nationally.

Wilmington's Christina Riverfront

Wilmington’s Christina Riverfront

The Christina River has its share of historic contamination. There are numerous contaminated sites bordering the river. Samples have indicated that there are toxics present at elevated levels in the water bodies of the Christina River watershed and fish consumption advisories have been posted for the river. According to the USEPA’s water quality standards the Delaware portion of the Christina River requires varying levels of pollution reduction for nitrogen, phosphorus and bacteria.

Although the Christina River has fallen victim to years of industry, improper land use and anthropogenic influences the story of the river is a positive one. The state is working diligently to clean up and redevelop the toxic sites along the river. The Christina River is also demonstrating improving trends for many water quality parameters. According to a recent article on water quality trends in Delaware’s streams by Gerald Kauffman and Andrew Belden, water quality trend analysis for long term (1970/1980-2005) and short-term (1990-2005) trends show improvement in the Christina River for numerous water quality parameters including: dissolved oxygen (DO), total suspended sediment (TSS), total phosphorus (TP), and total Kjedahl nitrogen (TKN). Positive trends for these parameters indicate improving conditions in the river. Additional parameters, including bacteria, which levels have historically been increasing, show a leveling off for long-term and short-terms trends over this same time period, another good news story.

We know that the Christina River is not a pristine, natural river system yet research shows that there are positive signs for the health of the water body. The efforts by so many locally, state-wide and regionally to improve the water quality has had a positive impact. And as the riverfront becomes more popular and a destination in the region, it is my hope that individuals will learn more about the river and help protect this valuable resource through individual stewardship. And over the years as I continue to walk along the riverfront I will feel fortunate to be able to share this river, which inspires and motivates me, with so many people, especially my son.

Join us at DEEC on April 16 at 3:30pm for National Water Dance to celebrate the Christina River through dance performances and exploration of the marsh for the wildlife calling it home.

To find out more about efforts to improve and protect our waters or how you can have impact, check out the Clean Water: Delaware’s Clear Choice campaign website, Facebook, or Twitter!

Evelyn Williams, Certified Naturalist and Volunteer Guide

Joe Sebastiani, Ashland Nature Center Manager

During the fall and winter months one of our the most frequent sightings in the Russell W. Peterson Urban Wildlife Refuge marsh is of Red-winged Blackbirds sitting on grasses or making short, low flights in small flocks from plant to plant.  Male red-winged blackbirds have black, glossy feathers with red and yellow shoulder patches on their wings. Females are a streaky brown color.

The male Red-winged Blackbird is glossy-black with a red and yellow patch on the wing called an epaulet. The female is streaky brown, and can be mistaken for a sparrow. Note her long, pointed bill, which a sparrow would not have.

The male Red-winged Blackbird is glossy-black with a red and yellow patch on the wing called an epaulet. The female (behind the male in this photo) is streaky-brown, and can be mistaken for a sparrow. Note the long, pointed bill, which a sparrow would not have.  Photo by Joe Sebastiani.

Red-winged Blackbirds are year round residents in this area. In the winter, Red-winged Blackbirds may also be seen flying as part of huge mixed flocks of over a million birds.  These enormous flocks also contain Common Grackles, Brown-headed Cowbirds, and European Starlings.  The flocks roost together at night in marshes and then head out to forage for food during the day.  The Delaware Bay region is known as a huge staging area for blackbirds in the fall and spring.  In fact, most of the entire northeastern North American population of these species stop in the Bay area…over 500 million birds.  (Birds of Delaware, Blackbird Roosts in Delaware.  J.T. Linehan.  pp. 523-4).  Watching these enormous flocks flying overhead is a sight to behold, and really one of the greatest natural spectacles in Delaware.  Listen as they go overhead, and hear the loud “whoosh” as the huge flocks drift past like smoke.  Just don’t open your mouth when you look up!

Some people think of these blackbirds as “ugly” or “dirty”.  Take another look at the individuals.  Grackles and Starlings have beautiful glossy plumage with an iridescence that changes with the light.  Who can deny the brilliant splash of red and yellow on a Red-winged Blackbird’s shoulder?  Appreciate them as adaptable beneficiaries of landscapes altered by human beings; allow yourself to be wowed by their impressive flights; take a finer look at a nearby individual and open your eyes to their subtle beauty.

In winter, Red-winged Blackbirds may fly 40 miles from their night-roosts in Delaware Bay marshes in search of food.  They seek out agricultural areas where they try to gorge on spent corn, as well as a wide range of weed seeds and any insects they can get on the ground.

Red-winged blackbirds are at home in the treeless environment of the marshes at the Dupont Environmental Education Center (DEEC) and perch during the daytime in grasses and cattails.  When spring comes they will nest low among the new shoots of these same marsh plants. Come out to DEEC and see if you can find a few, or a few thousand!

By Jim White: Senior Fellow for Land and Biodiversity

The Christina River has been one of my favorite Delaware canoeing and kayaking destinations for many years. Cruising with the tide on a late summer day is about as relaxing as it can get.  However, if you are like me, the best part of the experience is searching for wildlife such as American Beaver, Great Blue Herons or basking Northern Red-bellied Cooters and soaring Ospreys.  In the last several years, thanks to my friend Hal White (no relation) I have become very interested in dragonflies and the Christina River is a great place to see several of our common species. Scanning the spatterdock and cattails and other shoreline vegetation can result in observing colorful species such as Green Darner, Twelve-spotted Skimmer, Spangled Skimmer and Blue Dasher. However, my favorite species that makes the Christina its home is the Russet-tipped Clubtail.

A Russet-tipped Clubtail photographed by Jim White on the Christina River.

A Russet-tipped Clubtail photographed by Jim White on the Christina River.

This large species of dragonfly is only found on tidal freshwater rivers and is not particularity common elsewhere in Delaware. Hal White, in his book Natural History of Delmarva Dragonflies and Damselflies, wrote that this species was not recorded in Delaware until 2003 when a University of Delaware student collected it on the Christina River for his required insect collection. Why the species was not recorded earlier is a bit of a mystery but Hal speculates that large tidal rivers are not a place that most skilled dragonfly enthusiasts think of checking for uncommon species.  Since the 2003 lucky find, Hal has confirmed that the Russet-tipped Clubtail is actually fairly common on the river from August through mid-October.  However, although I had been up and down the Christina River many times over the years, I had never noticed this what I now consider, a rather conspicuous insect. That is, until 2008 when Hal and I mounted a mini-expedition by canoe to photograph this handsome dragonfly for his upcoming book.   It did not take long after putting-in, that we observed several Russet-tipped Clubtails patrolling low over the water.  But photographing flying dragonflies from a shaky canoe is a bit of a challenge to say the least.  Lucky for me though, one of them perched on an overhanging branch just long enough for me to get a few photos – mission accomplished.  So if you have a chance to get out along the Christina River keep your eyes peeled for Russet-tipped Clubtails.

A Russet-tipped Clubtail in flight, photographed by University of Delaware Professor, Dr. Michael Moore.

A Russet-tipped Clubtail in flight, photographed by University of Delaware Professor, Dr. Michael Moore.

Check out the next canoe trips on the Christina from the DuPont Environmental Education Center and see what you can find: Saturday, September 26 and Saturday, October 17

Natural History of Delmarva Dragonflies and Damselflies  by Hal White available at the Ashland Nature Center, DuPont Environmental Education Center, or on Amazon.com.

By John Harrod: Manager, Dupont Environmental Education Center

Blooming right now in the Russell W. Peterson Urban Wildlife Refuge is a great shrub of utility and beauty. The common elderberry (Sambucus Canadensis), also known as American elder, can be found throughout Delaware and along the Eastern U.S. from Canada to Florida. Elderberry is a pioneer species and sprouts rather quickly in areas of disturbance. Its haunts are wet areas including stream banks, ditches, moist meadows, marshes and swamps, which is why it can be found in our refuge.

Common Elderberry blooming along the boardwalk trail at the Dupont Environmental Education Center.  Photo by John Harrod

Common elderberry blooming along the boardwalk trail at the Dupont Environmental Education Center. Photo by John Harrod

This deciduous multi-stemmed shrub tends to have an arching habit and grows to 12 feet tall. Elderberry is quite vigorous and responds to pruning well, and will become quite dense through sucker growth making it a nice screen. Carpenter bees and mason bees tunnel into its soft pith of broken stems to construct nests for their young.

Common elderberry produces masses of white flowers in large umbels. The flowers are quite fragrant and attract many pollinating insects. The flowers are sometimes used to make elderflower water which is used in perfumes.

A close-up view of the Common Elderberry flower.  Photo by John Harrod.

A close-up view of the common elderberry flower. Photo by John Harrod.

After the blooms, elderberry produces fruits that are relished by at least 50 kinds of birds including American Robin, Cedar Waxwing, and Tufted Titmouse. People enjoy them too. Raw elderberries have an unpleasant taste and contain small amounts of poisonous alkaloids, so cooking is the way to go. The heat of cooking removes the toxins and improves the taste leading the way to delectables like jelly, preserves, pies, and wine.

The small fruits of the elderberry, which we will see later this summer, are eaten by a wide variety of birds.  Photo by H. Zell.

The small fruits of the elderberry, which we will see later this summer, are eaten by a wide variety of birds. Photo by H. Zell.

The refuge is open dawn to dusk daily, so come out and see the elderberry for yourself as well as the many other bloomers including the sweet scented Sweetbay Magnolia. While there, stop inside the DuPont environmental Education Center and ask a naturalist to lead you on a walk to find more plants.