Ian Stewart

American Goldfinches are one of my favorite birds. Their scientific name, Spinus tristis, translates as ‘Sad bird of thorn bushes’ and derives from their mournful rubber-duck like ‘squeak’ call. Personally, I think this name is unfair, as Goldfinches always seem such happy, colorful characters (like the female pictured below) with their jaunty, bouncy flight and excited twittering. They are common birds which can lead to them being overlooked and yet they have two major surprises under their wing.

The first is that they breed very late in the summer. Once you get past mid-August only a handful of birds are still breeding in Delaware but the Goldfinch is one of these select few, along with the related Indigo Bunting and Blue Grosbeak. The main reason we think Goldfinches breed so late is that they feed their young entirely on seeds, rather than invertebrates like almost all small birds, so they have to delay breeding until the seed heads begin to appear. The favorite food of Goldfinches includes Purple Coneflower (Echinacea purpurea) and Wild Bergamot (Monarda fistulosa), as well as a range of native and unfortunately, non-native, thistles.

Goldfinches build beautiful, densely-woven nests of fibrous materials such as thistle down and grasses in which they lay 2-5 bluish-white eggs (nest photographed at Bucktoe Creek on July 23).  The nestlings develop in around 2 weeks and fledge resembling duller versions of their parents with brownish wing bars and dark beaks (nestlings photographed in a different nest on August 5, just before they fledged).

The Goldfinches’ second surprise is that they are the only finch that molts their body feathers twice a year. Both sexes are a drab yellowish-green in the fall and winter, perhaps to avoid being seen by predators like hawks, but become brighter yellow in the summertime. The males are especially striking with their lemon yellow body, jet-black wings and cap, and white tail flashes.

The sight of a flock of Goldfinches feeding in a field of native thistle is enough to gladden the heart of any birdwatcher, and luckily Goldfinches are quite easy to attract to your yard, even in fairly urban areas. You can buy sock feeders of nyjer seeds or tube feeders made specifically for Goldfinches with thin seed ports. Since Goldfinches have such small pointed beaks they are the only common bird in our area that can reach inside and pick out the nyjer seeds. They will also happily eat black oil sunflower seed from a generic tube or platform feeder which has the added benefit of attracting other birds too. Better still, try planting some patches of Coneflower or native thistle in your yard and watch them feed how nature intended!

By: Tim Freiday, Middle Run Project Coordinator

The group of DelNature staff and volunteers get ready to set off on the annual Bio-Blitz in Middle Run Natural Area.

On Sunday, September 3, 2017, Delaware Nature Society held the annual Bio-Blitz at Middle Run Natural Area. Although rainy at 6:00 am, the skies cleared by 7:00 am and it turned out to be a very productive day with over 200 different species of organism recorded. In the park, 88 species of birds were recorded. Some of the highlights were 20 species of warbler including a Brewster’s Warbler (a rarely seen hybrid), Nashville, Tennessee, Blackburnian, Cape May, and Black-throated Blue and Green Warblers. We had birds everywhere we looked, and had some great views of many. The girdled Bradford Pears continue to provide quality looks at some real quality birds, with American Redstarts, Tennessee, Magnolia, Black-and-white, and Chestnut-sided Warblers perching alongside much larger Brown Thrashers and Gray Catbirds. We also had a continuing Alder Flycatcher who “pipped” only a few times, and Veery were around today. Surprisingly, a nocturnal Common Nighthawk was also flying around in the late morning.  Check out the close-up Northern Flicker below!


All of the checklists for the day in chronological order are at the links below:

There have been some excellent photos of some of the fall migrant warblers being posted on the Middle Run flickr account by the likes of Hank Davis and Derek Stoner. You can check out those pictures by following this link:

Around a 100 insects were identified at least to the family level with the help of UD entomologists Ashley Kennedy and Adam Mitchell. Some highlights from the arthropod realm include a Spiny Oak Slug caterpillar, Hickory Tussock Moth, Locust Borer, Ornate Plant Bug, Cicada Killer, Green Darner and many more. There was a very bright Red Admiral butterfly which must have just emerged. Participants learned about the food web of arthropods in our area, and got a glimpse of how complex it really is. Middle Run has a healthy mix of arthropods, with many predatory spiders and insects signifying an abundance of herbivorous insects. No wonder the birds like it here so much! It’s also not surprising that there are so many insects given the diversity and abundance of plants at Middle Run. At least 50 different species of plants were identified today, with many beneficial native species. Some are very showy and are flowering right now, like the Evening Primrose. We only found a handful of reptiles and amphibians today, but there were some nice ones such as Black Racer, Garter Snake, and American Toad.

Hickory Tussock Moth

Hickory Tussock Moth

This year’s BioBlitz showed how truly special and utterly important Middle Run Valley Park is for the multitude of life that our region supports. From the local birds and insects to the long distance migrants that refuel here, to the people that come and unwind by taking in the natural world Middle Run is a true gem that we should all be grateful for. In appreciating the importance of Middle Run we are shown the importance of conserving natural lands everywhere, and we are called to action to protect our natural world.

This past Tuesday was the first Tuesday Morning Bird Walk at Middle Run of the fall 2017 season. These walks are free and open to the public, and Delaware Nature Society staff will lead them each Tuesday at 8am through October.  The walks are sponsored by New Castle County Parks.  Come join us as we appreciate birds and nature!

Happy Birding!

Story and photography by Jim White, Senior Fellow for Land and Biodiversity

Although I have seen it many times, I still always pause at the sight of an American Kestrel. This smallest, and most colorful, of North American falcons is a master of flight. It can soar high — or hover dragonfly-like over open lands while searching for prey, suddenly plummeting downward, swooping onto some unsuspecting meadow vole or large insect.

As part of our ongoing cavity-nesting bird box program at the Coverdale Farm Preserve, seven American Kestrel nest boxes have been installed over the years and are maintained and monitored each nesting season. This year the Delaware Nature Society joined with a nationwide program that focuses on increasing the American Kestrel population throughout the United States. Surveys have indicated that the species has suffered dramatic declines throughout much of its range. The lack of adequate foraging habitat and nesting sites are possible reasons for this decline. As part of this nationwide program, Delaware Nature Society Land and Biodiversity Management staff have monitored the nest boxes weekly this year for adult activity.

Because the open meadows of the Coverdale Farm Preserve are excellent habitat for kestrels, we were confident that at least one pair would take up residence. We were not disappointed. On March 13th we observed a male perched on one of the boxes. Three days later a female appeared. Throughout the rest of March and into mid-April the pair was frequently seen hunting over the meadows of the preserve, catching meadow voles and jumping mice. Finally on April 23rd we discovered three eggs in the box. A few days later there were five eggs.

Then on March 31st we observed five, some may say “cute”, nestlings.

On June 14th, biologists from the Delaware Division of Fish and Wildlife captured and placed identification bands on the nestlings, so that they could be identified if recaptured in the future. The team also took measurements to determine the age and health of the nestlings. We were glad to learn that all five nestlings looked healthy and had plenty of body fat. After “processing”, the nestlings were carefully placed back into their nest box, and the team left them to continue to grow and fledge (probably in a week or so).

So next time you visit the Coverdale Farm Preserve be sure to look up: you may just see one of these beautiful falcons!

P.S. Interestingly enough, on June 9th, staff discovered a second active nest with three eggs. We are hoping that this nest will also be successful.

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