All posts tagged Delaware

By Ian Stewart

Delaware Nature Society has over 200 nest boxes spread around the properties we own or help manage which we installed to provide nest sites for a variety of birds. Every summer these boxes are monitored by a team of volunteers who track over 100 nesting attempts by 5-6 bird species (and we are always looking for more people to help with this – please get in touch if you’d like to get involved!). You’d be wrong to think the boxes stand idle throughout the winter however – it’s just that most of the action now takes place at night!

Several birds often roost in them during the winter, including Screech Owls, Eastern Bluebirds and some woodpeckers, which they probably do to protect them from the elements such as wind and rain. It is likely several degrees warmer inside a nest box than outside of it and for a small bird on a very cold night this could be the difference between life and death. Bluebirds take this a little further and are famous for ‘bundling’, where several birds squeeze into the same box for the night, probably keeping each other warm with their body heat.

A male bluebird entering a nest box

A male bluebird entering a nest box in winter

This year we’re making a special effort to check our boxes during the winter too. Sometimes it’s obvious that birds have been roosting in our boxes as they leave their droppings behind. The droppings in the photo below were almost certainly from a bluebird that has been eating Oriental Bittersweet. Bluebirds usually eat insects but at this time of year these are hard to find so they switch their diet to berries, and this exotic invasive vine is one of the few local plants that still has berries on it in February. You can help bluebirds in winter by planting berry-producing native bushes and shrubs such as Winterberry, Viburnums and Hollies. We will be following these boxes all through the year to see if bluebirds end up nesting in the same boxes that were used in winter.

Bluebird droppings inside a nest box

Bluebird droppings show they have been using this nest box

It’s also worth checking nest boxes in winter for less-desirable occupants. About 10% of our nest boxes are occupied by white-footed or deer mice during the winter. These nocturnal mice build fluffy nests inside boxes and sleep in them during the day. We always dump out mice and their nests during the winter, which may seem unkind but if left in place their urine and feces can damage boxes or carry disease, and birds won’t use boxes already occupied by mice. If you do this yourself, don’t use your hands to dislodge mice and their nests in case you pick up any disease or get bitten, but instead gently ease out the box contents with a stout stick.

Two deer mice fast asleep in this box

Two deer mice fast asleep in this box

This box at Coverdale Farm Preserve contained a furry nest with no fewer than 15 uneaten hickory nuts, which was interesting as this is not a common tree at the Preserve. These had probably been stored in the box by a Flying Squirrel, a nocturnal mammal which does not hibernate and requires food all winter. The squirrel cached the nuts here to provide a food supply for later in the winter, so to be sure the little guy wouldn’t go hungry we left the nuts below the box.

Hickory nuts cached in this nest box by a flying squirrel

Hickory nuts cached in this nest box by a flying squirrel

So just because you never see anything going inside your nest boxes in winter, don’t assume they aren’t being used!

Ian Stewart

Sparrows are a mystery to most non-birders (and many birders too!) and it’s not hard to see why. The great majority of them are small, brown streaky birds that at this time of year are usually just glimpsed as they disappear into a tangle of undergrowth, so much so that sparrow sightings often get lumped into the catch-all category of ‘Little Brown Bird’ (hastily scribbled as ‘LBB’ in field notebooks from here to Alaska).

This is a great pity as sparrows are an under-appreciated group of birds in my opinion, and Delaware is awash with them during the winter because several species that breed as far away as northern Canada flood into our area and flock together with our resident sparrows. Tangled brush piles and weedy fields might not be attractive to an average human but they are very popular with sparrows who love to scuffle through them in search of seed as well as take cover in them if a hawk appears. On a good winter’s morning you might see more than half a dozen species of sparrow just by slowly walking along the edges of these brush piles and fields and waiting for them to appear.

A simple first step to identifying sparrows is to look at their breast as this lets you place them into one of two broad categories: those with streaked breasts and those with unstreaked breasts. The collage below is composed of sparrows banded during DNS’s Bird Conservation Program and up close you can see the differences between species in breast patterning, as well as the eyebrow stripes, moustaches and thin crown stripe found in many sparrows.

Top row (L to R). Song, Fox, Savannah 2nd row. Lincoln’s, Field, American Tree (showing ‘stickpin’ in breast) 3rd row. Swamp, Chipping (winter), Slate-colored Junco 4th row. White-crowned, White-throated (adult), White-throated (immature)

The collage below shows the diversity of sizes, shapes and colors seen in sparrows’ beaks. For example, the beak of Song Sparrows is intermediate in length and depth while Fox Sparrows have a short but stout beak and both Lincoln’s and Swamp Sparrows have long, thin beaks. Some sparrows have all-brown beaks while others have beaks that are gray (White-throated), orange (Field), pink (Junco) or jet black (Chipping Sparrow during the breeding season). The American Tree Sparrow has the most distinctive beak of all, being dark brown above but yellow below. There is also quite a lot of variation in the angle of the forehead, the size of the eye, and the curvature of the upper beak.

Top row (L to R). Song, Fox (with 2 ticks!) and Field 2nd row. Chipping (summer), Chipping (winter), Savannah 3rd row. Lincoln’s, Swamp, American Tree 4th row. White-throated, Slate-colored Junco, White-crowned (immature).

Hopefully these photographs have convinced you that sparrows are more different and beautiful than you had thought. My advice is to slowly explore the undergrowth on a crisp, still winter’s morning and try to get a good look at every species you see. Rest assured, you will be rewarded!


by Dakin Hewlett, Watershed Education Coordinator

DEEC staff member tags and releases a Monarch Butterfly.

Visitors watch as a DEEC staff member tags and releases a Monarch Butterfly. Photo by John Harrod

Fall not only brings the oncoming burst of changing colors, but also marks the beginning of the monarch butterfly’s incredible migration to Mexico. The DuPont Environmental Education Center highlighted the butterfly’s unique journey at their 4th Annual Marsh & Monarch Celebration on September 23rd. Blue skies and sunshine greeted over 200 people who came out to celebrate the tagging and releasing of 8 monarchs. Leading up to the event, DEEC staff and visitors watched and waited as the reared butterflies transformed from caterpillar to chrysalis and finally to beautiful monarchs ready for release.

When the highly anticipated release date came, eager groups of visitors gathered on the boardwalk with a DEEC staff member to learn about monarchs and their important relationship to the milkweed plant. Adult monarch butterflies lay their eggs on the plant and the caterpillars then eat the milkweed as their sole food source. If you want to attract more monarchs to your garden, planting milkweed is a great way to do just that!

Each butterfly was then tagged with a special tracking sticker for research being done at the University of Kansas. Tagging helps monitor monarch migration patterns and the overall health of the population. Finally, the moment came that we had all been waiting for…A few lucky kids became wide-eyed as a butterfly was placed on their outstretched finger and took a few steps while deciding whether it was ready to take flight. Each time a butterfly took off the crowd clapped and cheered with enthusiasm as the magnitude of the 2,000-mile journey sunk in.

Canoeing the pond.

Canoeing the pond. Photo by John Harrod

Visitors also spent the day enjoying free, interactive activities throughout the marsh. Adults and kids alike enjoyed an on-the-water experience canoeing the pond, learning basic paddling skills, and attempting to navigate the water without getting stuck in the plants.

Many chose to get their feet wet while dip-netting for aquatic animals such as dragonfly larvae, scuds, and small fish. Dip-netting is not only a fun way to explore the pond, but is also a great tool to use when measuring water quality. By studying the biodiversity of the pond, staff members at DEEC can better understand the condition of the water. Guest staff from Stroud Water Research Center echoed that sentiment by providing visitors with a chance to conduct their own water quality tests. Participants turned scientists, learned how to test for pH levels, temperature, turbidity, nitrates, and conductivity with hands on experiments like the one shown below.

A curious visitor uses a turbidity tube to test the clarity of the pond water.

A curious visitor uses a turbidity tube to test the clarity of the pond water. Photo by John Harrod

Inside the nature center many other activities were underway such as “Zuumba like an Animal,” on the 4th floor. If you happened to saunter upstairs you were met with a group of kids hopping around the room like frogs or belting out animal sounds at the top of their lungs.  The 3rd floor stayed jam-packed all day with arts and crafts tables, a bike & kayak raffle sponsored by the Alliance for Watershed Education, and interpreters sharing all things marsh. The “Snapper Lab” on the 1st floor displayed many live animals that call the refuge home such as a black ratsnake, snapping turtle, and green frog. On the way out visitors stopped by to chat with Delaware Nature Society’s Habitat Stewards and left carrying armfuls of free milkweed to plant in their own gardens for the next generation of monarchs. Thank you to all who came out to celebrate and see you next year!


Free milkweed plants and art projects to take home after a wonderful day at the marsh.

Free milkweed plants and art projects to take home after a wonderful day at the marsh. Photo by John Harrod

By Sally O’Byrne, Trip Leader
Photos by Robert Tuttle, Jr.

A wastewater plant may not be the first place that comes to mind to look for birds, but many birders know the secret; They can prove to be quite good places to find gulls and waterfowl, often unusual in timing or species. Our local plant, operated by Veolia, is known as a great place for ducks which can be found in great numbers on the ‘polishing’ ponds adjoining the river.   Polishing ponds are the very last stage of a series of processes that separate solids from water and then cleans the water enough so it can be discharged to the Delaware River.

Aerial photo of Veolia Waste Water Plant

Aerial photo of Veolia Waste Water Plant

The wastewater that travels through sewers and enters the plant is called ‘influent’, and the first step is a mechanical bar screen that removes rags, paper, and other articles larger than a centimeter. Those screenings go to a landfill.   The ‘effluent’ (wastewater that exits) is then channeled into a grit chamber where the velocity is slowed down and the heavier grit, sand, and gravel settle out and are removed.

A large drum removes rags, paper, and other articles larger than a centimeter

A large drum removes rags, paper, and other articles larger than a centimeter

After leaving the grit chamber the wastewater enters a primary clarifier, where velocity slows again and additional suspended matter, typically organic, settles to the bottom forming a sludge layer. Greases and oil and other floating matter, rise to the top and form a scum layer.   Slow rotational scraper blades move the sludge to a hopper at the bottom of the clarifier and a skimmer on the surface directs the scum to another collector.

Empty and full clarifier

R to L: Empty and full clarifier


Now comes the secondary treatment; the wastewater flowing out of the primary clarifier goes into aeration basins where it is exposed to living organisms and bacteria that consume most of the organic matter in the wastewater. The water is bubbled to supply the microorganisms with the oxygen they need. In about 3 hours, the time it takes for the water to pass through the aeration tank, most of the organic matter has been consumed. (photo of aeration basin)

aeration basin

aeration basin

The secondary clarifiers receive the mixed liquor (wastewater and microorganisms) from the aeration tank. Here the scum on top is once again skimmed off and the activated bacteria that has settled to the botton is scraped into a hopper and then returned to the aeration chambers. The microrgasims will have increased through reproduction, so the excess are removed as sludge. The clear water leaving this basin now goes for Tertiary treatment. Here we have a group of Ring-billed Gulls enjoying the ‘fruits’ of Veolia’s efforts at the clarifier!

Ring-billed Gulls reaping the benefits of the clarification process

Ring-billed Gulls reaping the benefits of the clarification process

Throughout this phase, removed sludge is taken to an anaerobic chamber which gives off methane as it further digests the sludge. The methane is ‘flared’ and the final digested sludge is dewatered. It now looks and smells like humus and can be sold for non- edible application (e.g. golf courses).

A methane flair

A methane flair

Tertiary treatment happens in the large Polishing Ponds, the desired destination of avid winter birders. It takes about 3 days for the water to move through these ponds, where further settling and bacterial action take place. As a final treatment, the water is given a dose of bleach before it is sent into the Delaware River. The effluent entering the Delaware is tested daily for fecal coliform and other pollutants.   It is discharged through a pipe in the middle of the river at a depth of approximate 35 ft.

Waterfowl floating on the polishing ponds

This photo is from December 14, 2008, but shows the sorts of waterfowl number that are here in Winter.

We spent the final portion of our tour looking at a variety of ducks in the polishing ponds. In most places in New Castle County, the waterfowl have already migrated North, but here in this protected spot, we had a nice show.   On our trip, we had far fewer ducks than can be found in mid-Winter, but we had a nice variety; Gadwall, Mallard, Northern Shoveler, Ring-necked Duck, Lesser Scaup, and Ruddy Duck . We counted 23 species of birds for the day at Veolia Waterwater Treatment Plant – not bad for a place where most folks just want to hold their nose.

A Lesser Scaup duck floating in the polishing pond

A Lesser Scaup duck floating in the polishing pond