Bald Eagle Eggs: A Brief N.J. History Lesson

Written By: Jim Wright  for Duke Farms and Conserve Wildlife Foundation

Our story thus far: The female Bald Eagle has laid two eggs this season, on 2/16-17 and 2/20. You can view the nest on streaming video here.

For much of the 20th Century, Bald Eagle eggs were under a huge threat in New Jersey and elsewhere — first because of  egg collectors and later because of DDT.

The great naturalist and author John Burroughs wrote in his 1904 book Far and Near that “I once heard a collector get up in a scientific body and tell how many eggs of the Bald Eagle he had clutched that season, how many from this nest, how many from that … I felt ashamed for him. He had only proved to be a superior human weasel.”

DDT DSCN0057-001According to a 1936 report commissioned by the National Audubon Society, oologists  (egg collectors) had robbed three of the five nests in Cape May County the year before, and a Salem County nest had failed to produce young over a 15-year period because of egg collectors.

As Bruce E. Beans wrote in his 1996 book The Eagle’s Plume, “A bird such as the Bald Eagle, with a relatively long sexual maturation period and relatively low reproductive rate — and average of two a year, with often the first hatched the only survivor — could not long endure such thievery.”

The next threat to Bald Eagles and their eggs was the overuse of the insecticide DDT, beginning after Word War II.

Some of the toxic chemicals in the pesticide got into the food chain and were absorbed into the body fat of Bald Eagles and other animals.

Because Bald Eagles have fairly long life spans (up 40 years in the wild)  the  DDT accumulated in the body fat and affected the Bald Eagle’s reproduction. Continue reading

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All About Duke Farms’ Bald Eagle Eggs

(Click on an image to enlarge)

Written By: Jim Wright  for Duke Farms and Conserve Wildlife Foundation

Our story thus far:  The female Bald Eagle has laid two eggs this season, on 2/16-17 and 2/20.

“A box without hinges, key, or lid,
Yet golden treasure inside is hid.
   — J.R.R. Tolkein, The Hobbit

With the arrival of eggs in the Duke Farms Bald Eagle nest, the nervous season has begun.

Two eggs -- no snow but cold temperatures

Two eggs — no snow but cold temperatures. Eagle Cam viewers can get nervous when the adults leave the eggs.

Watching the two adult eagles incubate the eggs —  a process that typically takes five weeks — can often seem a bit ho-hum.

But  when the eggs are left unattended in colder weather — even for a short spell — it can be nail-biting time.

So let’s address that big question right away: Should folks be worried when both eagles leave the nest?“

“We’ve had several inquiries about this, and we had similar concerns when we first started watching the camera after it was installed,” says Thom Almendinger, Duke Farms’ Director of Natural Resources.


This is a replica Bald Eagle egg photographed next to a U.S. quarter (eagle side up) for size comparison.

“But this is an experienced pair that has successfully hatched 19 or 20 of the 21 eggs it has produced. The adults instinctively know to sit on the eggs when they need heat and get off them when they need to be cooled.”

[Note: As the Eagle Cam Page FAQs explains: In 2009 and 2010 it was noted that both the male and female were N.J.-banded birds, because they each had a green color band on one leg and a silver federal band on the other. In 2011, there was a new female in the pair, which we know because she was not banded.]

Kathy Clark, a wildlife biologist for the N.J. Endangered and Nongame Species Program adds: “Eggs are okay getting chilled for the first few days, before there is much development. They can’t freeze, though, without some permanent damage to the embryo.”

In short, this is wild nature and nothing is certain, but there may be bigger things to worry about.

Now, a few egg fundamentals. Eagle eggs may look small in the nest, but they are larger than many folks might think.

The eggs, a dull white or off-white, are the size of lop-sided tennis balls and weigh a quarter of a pound. Continue reading

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Eagle Cam Update: Second Egg Arrived Friday P.M.

The Duke Farms Bald Eagles are now on two eggs. (Click on each image for larger view)

The first arrived late Monday/early Tuesday, and the second arrived on Friday around 2:30 p.m., when the temperature was around 15 degrees.

Last year, the eagles had three eggs, three days apart, beginning on Feb. 17.

Incubation is typically 35 days. Nothing is certain, especially in the wild.

                                                                                            — Jim Wright

Jim Wright’s next weekly post on the Duke Farms eagles arrives Wednesday at 1 p.m. The topic, appropriately, will be all about eagle eggs.

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A New Weekly Post: From the Eagle’s Perch

Screen Shot 2015-02-16 at 5.28.55 PM

Monday, both eagles were on the nest at 5:28 p.m.

Written By: Jim Wright,  for Duke Farms and Conserve Wildlife Foundation

Welcome to Duke Farms’ 2015 Bald Eagle nesting season.

The live streaming video  from the Eagle Cam, which has been on-line since the 2008 nesting season, offers an extraordinary window on nature to anyone with Internet access.

People have watched the Duke Farms Eagle Cam more than 9.4 million times. To expand that coverage, I’ll be writing a weekly post that goes online at 1 p.m. each Wednesday during nesting season.

Now that the pair are incubating at least one egg, let’s begin with some basics — with a caution that previous nesting seasons may not reflect this year’s outcome.

In nature, anything can happen. No one should count their eaglets before they hatch (or fledge).

At Duke Farms, a nest was discovered near the Raritan River in the fall of 2004, and a pair of Bald Eagles began using the nest the following spring.

With the help of Conserve Wildlife Foundation of New Jersey, Duke Farms installed a video camera in a nearby tree in early 2008 and began the streaming video began that March.

Screen Shot 2015-02-16 at 5.29.09 PM

At 5:29 the male flew and the female remained.

In October 2012, Hurricane Sandy destroyed the nest. Two months later the eagles built a new nest in a Sycamore 100 yards away. Duke Farms and CWF moved the video camera to the new nest tree in the fall of 2013.

Since 2005, the female has laid between one and three eggs per clutch.

Last year, beginning on Feb. 17, the female laid three eggs — each three days apart and in the afternoon. This year the female has laid one egg so far, either on late on Feb. 16 or early on Feb. 17. Continue reading

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From Green to Clean: Closed Loop Lake System

The Lakes at Duke Farms. The Raritan River can be seen at the top of the photo.

The Lake System at Duke Farms. The Raritan River can be seen at the top of the photo.

Written By: Jon Wagar, Director of Operations.

Duke Farms is hard at work trying to change our lakes from green to clean. As anyone who visits the property during the summer sees, our man-made lake system contains excessive amounts of algae and aquatic vegetation. It not only is an aesthetic issue, but it provides less than optimal habitat for wildlife and can lead to fish kills.

There are several things that cause the growth of algae and other vegetation. With hydrological consultants from Princeton Hydro and engineers from MWH, we’ve developed a 3 phase multi-year project to help address this problem. The first phase, the installation of a new well to provide water to the reservoir, was completed in mid-August.

This power station is where the hydro-electric power for Duke Farms was generated. The pumping house had a capacity of one million gallons per day. A pipe laid under the river connected the pumping house to the two million-gallon Duke Reservoir.

The pumping house had a capacity of one million gallons per day. A pipe laid under the river connected the pumping house to the two million-gallon Duke Reservoir.

Previous to installation of the well, Duke Farms pumped approximately 700,000 gallons of water a day from the Raritan River to the Duke Reservoir, our highest-elevation lake. Water pumped to the Reservoir flows by gravity through all the lakes and back into the Raritan River. Amazingly, like much of the infrastructure at Duke Farms, this River pumping was originally designed by James Buchanan “Buck” Duke and still works over hundred years later!

Although there is plenty of water in the river and we replace at least as much as we take out, the water quality is not great. River water contains nutrients from runoff from agriculture and lawns upstream as well as other non-point source pollutants. It also tends to be fairly warm, and warm water holds lower levels of oxygen. These nutrients may be good to grow lawns and corn, but when they runoff into the river they also grow aquatic vegetation and algae.

New Lake System Well

New lake system well installed near Duke Reservoir.

The water from the new well will initially replace some, but not all, of the water that we pump from the River. Well water is much cleaner than the river water, is colder and holds more oxygen, and will help starve the excessive aquatic vegetation of nutrients while also providing better habitat for fish and other aquatic organisms. We also hope that eventually, we can stop pumping from the river altogether.

The second phase, which we recently begun, will entail the installation of a recirculation pump that will pump water from the lowest elevation lake back to the reservoir. The recirculation pump will cause increased flow of water between the lakes and therefore decrease the nutrients that are leached out of the sediment in the lake bottoms. Once it is fully functional, it should also allow us to completely stop pumping from the Raritan River.

Third, we are exploring the harvesting of algae and other aquatic weeds to reduce the nutrient load in the lakes. Since these plants contain excessive amounts of nutrients, we also plan to add them to our composting operations, where we actually can use these nutrients to make richer compost for our community garden and incubator farm.

The final phase will be installation of bubblers. Bubblers will increase dissolved oxygen near the bottom of the lakes and also help stop nutrients from the sediment from leaching into the water.

Stay tuned as we continue to make our improvements to our lakes and make them more appealing for wildlife and people!

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Late Blooms in Landscapes

Written by: Kathleen Salisbury, Duke Farms Manager – Education.

As you walk around Duke Farms this fall you might notice the leaves changing color on the trees, shrubs and even the perennials!  But as you explore, be sure to take note of the flowers still blooming throughout the property.

Late blooming flowers are essential in a landscape that aims to provide late season food to migrating song birds and insects preparing to make it through a deep freeze in a few weeks.  The nectar from these flowers provides much needed energy to insects, while ensuring a crop of seeds and the next generation of native flowers.  Insects attracted to these plants and their seeds provide a high energy food source to many types of birds including those that fly south for the winter and those that call Duke Farms home, no matter what the season.

Remember when planning your own landscape as a habitat for wildlife, diversity is key.  By ensuring you have many species of native plants blooming throughout the year you will ensure a diversity of wildlife in your garden.  The trick to attracting winged wildlife is to make sure they can see your offerings from above.  Plant your natives in groupings of three or more, the large area of color will indicate to small eyes above that you have food for them below. Enjoy the autumn color of leaves, wildlife and even flowers at Duke Farms and your own back yard!

Some of the flowers you may see blooming, and should be considered for your home landscape are:

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Rain Gardens: a beautiful way to keep the rain from the drain

By: Heather Desko, New Jersey Water Supply Authority.

In recent years, I hear more and more people striving to be “green” and do their part for the environment—I love it! They drive hybrid cars to use less fossil fuel, they use reusable shopping bags to use less plastic, and they use energy- and water-efficient appliances to use less electricity and water. Here’s a new challenge: install a rain garden so less polluted runoff reaches our precious drinking water supplies.

Rain Garden in front of house. Photo by: Heather Desko, New Jersey Water Authority.

Rain Garden on the side of a residence.
Photo by: Heather Desko, New Jersey Water Supply Authority.

A rain garden is a landscaped, shallow depression that is designed to soak up rain water and runoff. As rain falls to the earth, some of it evaporates, some is used by plants, and some goes down into the soil. The rest of the rain flows across the land surface collecting pollutants and carrying them to rivers and reservoirs that are sources of our drinking water.

Rain gardens are designed to collect water primarily from rooftops, but also from driveways and patios. They look like regular flower gardens, but when it rains, a rain garden will hold a few inches of water and allow it to slowly filter into the ground instead of running into storm drains and streams. Native plants, especially ones that are used to being wet, are a great choice for rain gardens.

Rain gardens are not a good solution for areas that are always wet—that means the soil does not drain well. A rain garden should drain within 24-48 hours. If you have a basement, your rain garden should be at least 10 feet away from your house, and you should avoid your septic system (if you have one). Don’t forget to call to locate underground utility lines before you dig—NJ One Call Hotline 811.

If you are a Somerville, NJ resident and want to learn more about rain gardens, join us for informational workshops at Duke Farms on Thursday, August 22, 6-8pm and Saturday, August 24, 10am-12noon. Register here.

Visit the New Jersey Water Supply Authority’s rain garden webpage for more information about local rain gardens. You can download a free copy of the NJ Rain Garden Manual by the Native Plant Society of New Jersey and Rutgers Cooperative Extension Water Resources Program.

Are you a Somerville resident? Then you are in luck: free workshops, free design consultations and rebates for installing a rain garden are available! To learn more about the rebate program, click here.

Happy planting!

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It’s Firefly Season!

Written by: Hannah Davelman, Duke Farms Education Volunteer.


Photo By: Ashley Harrigan

Driving down River Road at night, it’s clear that summer has arrived in full force. The air is hot and humid, the insects and toads are calling at full volume, and the trees are full of tiny flashing lights- it’s firefly season! After up to two years spent underground in their carnivorous larval stage, they emerge in early to mid-May to glow and develop into pupae, then fully-grown adults! Once they develop into adults, they can be seen searching for a mate via their distinctive flashes.

Though fireflies can be found all over the world, in North America they’re almost never seen west of the Rockies. This surprises many who grew up on the east coast, to whom the little critters are synonymous with summer nights. We can also be surprised by the sheer number of names given to fireflies- Lightning Bugs and Fireflies seem to be interchangeable, but glow-worm can alternately refer to the glowing larvae, or certain species of wingless female fireflies. It’s hard to keep them all straight!

Despite being nearly ubiquitous on the east coast, most people are completely oblivious to the lives of the fireflies in their yard. For example, I had no idea that New Jersey is actually host to several different kinds of fireflies, each with their own unique flash pattern. I also had no idea that adult fireflies only live for a few weeks, making it all the more important that kids and adults handle them with care and make sure to release them after admiring their flashing lights.

As New Jersey becomes ever more densely populated, the local firefly populations have begun to dwindle as they have in many parts of the world. Nobody’s entirely sure why this is, but researchers at Boston’s Museum of Science have some ideas. They suggest that the use of certain pesticides, as well light pollution and decreasing open space can impact firefly larvae, as well as adult fireflies, and harm the population. To get involved with their efforts to track firefly populations, and learn more about these little beetles, visit the Firefly Watch homepage on the Museum of Science website- or, you can come to Duke Farms’ Firefly Festival!

The inaugural Duke Farms Firefly Festival will take place on Friday, July 12th from 8-11 pm, and will feature a night of firefly-centric education and activities for kids and adults. Bring your flashlight and your walking shoes, and learn more about the fascinating creatures in your backyard!

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Dam Removals in New Jersey – How Did We Get Here?

Dam Removal

(Dam removal) will result in a significant environmental improvement to the Raritan River, making this a valuable habitat for fish spawning, improving overall environmental conditions in the river system, and expanding recreational opportunities,” –  NJDEP Commissioner Bob Martin

Written by  . Published June 25, 2013

In the aftermath of Hurricane Floyd in 1999, it became painfully evident that the many dams in and around the state were woefully obsolete. Obsolescence occurs on a dam when it, either through climactic changes or antiquated designs, is unable to safely pass those infrequent yet highly destructive floods. Obsolescence can also occur when earthen embankments or concrete structures have deteriorated to the point of no longer providing safe resistance to seepage and impounding water behind the dam. The threat to the public living in the path of a potential flood wave that results when a dam suddenly bursts is varied but can have serious consequences and liabilities for dam owners.

Following the hurricane, the NJDEP Bureau of Dam Safety sent letters to all the dam owners in their records reminding them of their obligation to maintain their regulated structures in compliance with the Dam Safety Regulations. It was serendipitous that, at the same time, American Rivers and the National Oceanic and Atmospheric Administration (NOAA) started a program called the “Community-Based Restoration Program River Grants,” whereby grants were made available to remove obsolete dams to allow for migratory fish passage. The Natural Resource Conservation Service (NRCS) and the US Fish and Wildlife Service (USFWS) at the same time started looking to dam removals as meeting the restoration criteria for their funding programs.

(to read more, visit the Princeton Hydro blog here.)

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Welcome to the Neighborhood

Written by: Nora Wagner, Director of Programs


We all know “that” guest that comes to visit, talks too loud, doesn’t look very nice and informs us they will be back. Well, nature has its own version of this and it is time to prepare for the Cicada.

Natural phenomenon such as the 17 year cicadas are events that are often times embroiled in legend.  Aspects of such events that people remember from their childhoods for example often overtakes the reality of the situation.

Looking at the headlines, the uninformed might think the end of times was nearing. From the really fright inducing- “How to Survive a Plague: Insect Edition” (Huffington Post), to the slightly alarming – “Billions of cicadas to infest the East Coast” (NBC’s Today Show), to the downright exploitative –  “Everything You Need to Know About the Impending Cicada Sex Invasion” (The Atlantic Wire), the fear mongering topic of the season is all about cicadas.

Is any of this based on science? Does unattractive and noisy mean dangerous? In the case of the cicadas, the opposite is true. They are among the most misunderstood maligned little visitor and it is time to clear up a few myths.

Here are 5 of the most popular urban legends causing concern about the impending cicadageddon:

Myth: Cicadas are invading the East Coast and you should stay in your home.

cicada shells can be composted

Cicadas just want some lovin’. How can you not admire that?

Fact: They do swarm at times, but they won’t harm you.  If you are running landscape equipment you may find yourself at the center of a cicada love fest.. Don’t worry – they’re just showing that they are “turned on” for your power tools that vibrate, attracting a male cicada response.

Myth: Cicadas are poisonous to animals and humans.

Don't be afraid of our cicada friends!

If you’re on the Atkins diet, cicadas are yummy indulgences!

Fact:  Unless you spray them with toxic chemicals ( and please don’t!), cicadas are not poisonous, and in fact are eaten by some people. Cicadas are low in fat, high in protein and carb free…  so if you are on the Atkins diet, indulge at will.

Myth: Cicadas only appear once every 17 years.

washington post brood map

Source: Cicada researcher John Cooley via The Washington Post. Published on April 9, 2013, 7:13 p.m.

Fact: There are two types of cicadas – annual and periodic. Periodic cicadas are the species that appear once every 13 to 17 years, and each brood staggers life cycles and occupies a different geographical location.

Myth: Cicadas damage trees and shrubs.

Fact: Damage caused by nymphs feeding on plant roots is very minor. The adults do not feed on the upper portions of the tree after they emerge, and females laying eggs cause minor damage to small branches where eggs are deposited. It may be tempting to treat trees with insecticides, but there is no real reason to do so. In fact, molted cicada shells can be collected and used in garden compost.

Myth: Cicadas are locusts.

The Pennsylvania Department of Forestry knows the difference between cicadas and locusts - do you?

The Pennsylvania Department of Forestry knows the difference between cicadas and locusts – do you?

Fact: Don’t start planning your apocalypse party yet. Locusts are in the same family of insects as grasshoppers. The confusion exists because both locusts and cicadas emerge in periodic swarms.

At Duke Farms, our mission is to be a model of environmental stewardship and to inform visitors how to be informed stewards of the land. One of the great things we do is to draw attention to some of the natural wonders that are strange, wonderful and magical. Cicadas are part of the cycle of nature.  We encourage you to treat your house guests well, because we promise you they won’t be back for a while!

For more information on cicadas, please visit and we also recommend this innovative cicada tracker via WNYC’s RadioLabs found at

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