American Kestrels at the Coverdale Farm Preserve

Posted by Shannon Giordano on June 22, 2017
Posted in: Birds, Coverdale Farm. Tagged: . 2 comments

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.

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Looking for Birds in Strange Places

Posted by Shannon Giordano on April 12, 2017
Posted in: Birds. Tagged: , , , . Leave a Comment

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

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Lifting the lid on the life of birds

Posted by Ian Stewart on March 21, 2017
Posted in: Ashland Nature Center, Birds, Burrows Run Preserve, General Ecology, Uncategorized. 2 comments

Ian Stewart, Ornithologist

One of the best ways to connect with nature is to monitor bird nest boxes. Regularly checking the contents of an active nest box lets you watch the whole breeding cycle unfold before your very eyes! It starts with nest building, progresses through egg laying and nestling rearing and then (hopefully) ends with the young birds successfully leaving the nest.

IMG_2236

Using an mirror to count Bluebird eggs

The Delaware Nature Society has a team of eager volunteers who monitor over two hundred boxes spread throughout several properties and every year brings more data and surprises. Our most common occupants are Tree Swallows, Eastern Bluebirds and House Wrens but most years we attract a few Carolina Chickadees, Carolina Wrens and Tufted Titmice. One year we had a White-breasted Nuthatch use one of our boxes – who knows what species might show up next?!

Chickadee on nest

Opening this nest box revealed a Carolina Chickadee sitting tightly on a nest. In these cases we leave the bird alone and retreat.

Checking boxes lets you see for yourself the many differences between each species in the way their nests are built, the shape and color of their eggs, and the appearance of their nestlings, as well as the nesting quirks of different birds. Did you know for instance that House Wrens often add spider cocoons to their nest, probably because the spider hatchlings eat arthropod pests mixed in among the nest lining?

Wren nest with spiders

House Wren nest lining dotted with spider cocoons

Our boxes remain in place year-round and provide winter refuges for both welcome and (slightly) unwelcome guests. Eastern Bluebirds roost in our boxes overnight during the winter, presumably to help them stay warm, and sometimes bundle together in the same box. Last winter one of our boxes at Coverdale Farm Preserve had an enlarged entrance hole and was filled with acorns from the huge old Red Oaks that line the driveway. This was probably a squirrel using the box to cache a supply of acorns to chomp on if a sudden snowfall made food hard to find.

chewed box

acorns

Mice also like to spend the winter in our boxes so we have to bump them out to allow the birds to nest. Can you spot the two mice jumping out of the box?

mice2

We have been cleaning out our boxes to get them ready for spring and the birds are checking them out already so nesting isn’t far away! We can always use an extra person or two to help monitor nest boxes at Coverdale Farm or the Red Clay Reservation near Greenville, or Abbott’s Mill near Milford, so if you want to get involved just give us a call on (302) 239-2334. Boxes only need to be checked once a week and monitoring them makes a great excuse for talking a walk on a summer evening or weekend at these beautiful sites. All of our data are submitted to Cornell University’s ‘Nest Watch’ scheme so we are contributing to science as well as simply enjoying nature.

If you’d rather put up your own nest boxes why not join our upcoming program (April 27th at Ashland followed by a field trip to Coverdale on April 29th) to get advice on how to design and position boxes in order to attract nesting birds to your property? Having birds nest in a box you built yourself is a tremendously satisfying experience that may be repeated for many summers to come!

Tree swallows on box

A pair of excited Tree Swallows start building their nest in a brand-new box

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Spring in Winter!

Posted by Joe Sebastiani on March 1, 2017
Posted in: Ashland Nature Center, Botany. Tagged: , , , , . 1 comment

By Joe Sebastiani, Ashland Nature Center Manager

In these not-so-wintry days with temperatures in the high 60’s, you are the only creature fooled into thinking it is spring.  Plenty of plants, and an abundance of animals are responding as though it is April.  During a walk at Ashland today, with 68 degree heat, I noticed some things that weren’t showing themselves this time last year.  The most exciting show at Ashland right now is the emergence of Wood Frogs.  Get out to Ashland within the week if you want to catch the action.  As I write this, the sound of the male’s “quacking” is percolating through my open window along with a warm breeze.  Listen to the short audio clip of the Wood Frogs calling from a small pond next to the Ashland Nature Center.

Male Wood Frogs like this one are currently "quacking" away, in the hopes of attracting a female to join him in the water.

Male Wood Frogs like this one are currently “quacking” away, in the hopes of attracting a female to join him in the water.

Wood Frogs lay clumps of eggs that will soak up water after they are laid.  The ones below my hand are newer than the ones on my hand.  Can you see the difference?

Once a male and female Wood Frog find each other, she will lay eggs such as these, and the male will fertilize them.

Once a male and female Wood Frog find each other, she will lay eggs such as these, and the male will fertilize them.

Although the American Bullfrog won't lay eggs until later in spring, I was surprised to see one surveying the scene at Ashland on this warm 1st day of March.

Although the American Bullfrog won’t lay eggs until later in spring, I was surprised to see one surveying the scene at Ashland on this warm 1st day of March.

A walk along the floodplain at Ashland Nature Center revealed several plants beginning their growth cycle for the year.  Several are non-native, invasive plants, but others are native.  The warm weather is giving these plants an early start this year, but it isn’t completely unusual.

Snowdrops are an ornamental, non-native plant that is found in the wild sometimes. They are always the first sign of spring here at Ashland, and they are in full bloom currently.

Snowdrops are an ornamental, non-native plant that is found in the wild sometimes. They are always the first sign of spring here at Ashland, and they are in full bloom currently.

Lesser Celandine is blooming along the Red Clay Creek at Ashland right now. Unfortunately, it is a non-native, invasive species that is devastating wildflower diversity along waterways in our area by smothering the native wildflowers.

Lesser Celandine is blooming along the Red Clay Creek at Ashland right now. Unfortunately, it is a non-native, invasive species that is devastating plant diversity along waterways in our area by smothering the native wildflowers.

This Skunk Cabbage is a native wetland plant that is already sending up its leaves in the wet forest.

This Skunk Cabbage is a native wetland plant that is already sending up its leaves in the wet forest.

The small, red female flower of the American Hazelnut is in bloom, but you have to look closely to find it!

The small, red female flower of the American Hazelnut is in bloom, but you have to look closely to find it!

The long, yellow male flowers of the American Hazelnut are much easier to see. This is always one of the signs that native plants are starting the new growth year, and it is fun to spot these shrubs in the woods right now, when they tend to blend in later on in the year.

The long, yellow male flowers of the American Hazelnut are much easier to see.  It is fun to spot these shrubs in the woods right now when they are more obvious.  They tend to blend in later in the year, making them tough to see.  Can you find the small, red female flowers in this photo?

One of the early signs of spring I have NOT noticed yet is the Groundhog.  My guess is that during this early warm spell, they have decided not to show their faces, after  predicting we would have six more weeks of winter.  WRONG!!

Finally, the insects are also out and about.  I have seen Anglewing butterflies, true flies, a dragonfly, and many smaller, unidentifiable forms buzzing around lately.  The prize in this category, however, goes to the inch-long larvae of one of our firefly species that we found crawling on Ash trees.  We found dozens of them, and watched as they scampered around the trunks, looking for smaller insect to eat.

This large Firefly larva was crawling around the trunks of trees on the floodplain. They must have recently emerged, since there were dozens of them. These insects will dine on smaller insects they can catch as they slink up the trunk.

This large Firefly larva was crawling around the trunks of trees on the floodplain. They must have recently emerged, since there were dozens of them. These insects will dine on smaller insects they can catch as they slink up the trunk.

 

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