Updates from the PA Farm Country Bald Eagle Nest
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Join the Game Commission in celebrating Pennsylvania's growing bald eagle population. Immerse yourself in this view from the top of a big sycamore tree nestled in Pennsylvania farmlands. Bald eagles are wild creatures and it is important for us to keep them wild. Please refrain from naming the birds to respect them as wild animals. Also respect the privacy of the birds and the landowners, to whom we are extremely grateful for their enthusiastic cooperation in allowing us to share this peek into the lives of bald eagles. Periodic updates will be posted here and in the livestream chat. Enjoy! And remember, nature can be difficult to watch.
History at this site:
Eagles have nested in this vicinity for at least 15 years. It is believed that when a nest collapsed about three miles away, the pair built a new nest at this location. The eagles nesting in this area have successfully reared three young most years. Two adults were spotted adding nest material since the cameras were installed in late October 2019. The nest held three eggs, arriving Feb. 13, 4:24p; Feb. 16, 2:31p; and Feb. 19, 3:03p. Two eggs hatched; the first eaglet was seen early on March 25 and the second early on March 27. One of the adults moved one of the eggs out of the nest on March 26, presumably because something was wrong with the egg.
Bald eagles in Pennsylvania:
The bald eagle's history in Pennsylvania is a precarious one. Only 36 years ago, there were a mere three nests left in the entire state. With the help of the Canadian government, the Pennsylvania Game Commission and several other states reintroduced bald eagle chicks from Saskatchewan to the Northeast United States. Today, Pennsylvania boasts more than 300 nests and the species is no longer state listed as threatened or endangered. They remain protected under the Bald and Golden
Eagle Protection Act and the Migratory Bird Treaty Act. This 22-minute documentary tells the story of that success.
Learn more about Pennsylvania bald eagles at http://bit.ly/PGCEagleCam.
Really tired….or not? While watching the eaglets you seem them frequently yawning. It may not be because they are tired. One option is that they are moving food from their crop, which is like a “doggy bag” down to their stomach. Many birds eat as much as possible when the opportunity for feeding presents itself, like when the adults bring a fish to the nest. This food can’t possibly be digested this quick. The crop enables the bird to fill up and then the bird can do the digesting later when it has time to rest and avoid predators that may be lurking nearby while the bird is in the act of eating. A second reason they may be yawning is that it may serve as a sort of thermoregulatory behavior. In some experiments with parrots, scientists discovered that those birds yawned more frequently the hotter the temperatures.
Why don't birds fall out of trees when they sleep? Two tendons run from a bird's leg muscles down the back of the leg and attach to the toes. When a bird lands on a perch and its legs bend, the tendons tighten and the toes grab onto the perch. This adaptation allows a bird to stay on perch, even while asleep. Some birds can even sleep with one eye open and half of their brain alert, allowing the sleeping bird to spring into action quickly if a threat approaches.
Not Really Bald: The bald eagle's scientific name, Haliaeetus leucocephalus, means "white-headed sea eagle." The word "bald" is a misnomer. The mature eagle's head is covered with gleaming white feathers. Its body is dark brown, its tail white. Immatures are brown, mottled with white on their wings and body. Full adult plumage is attained in the fifth year. Their bills change from dark to more yellow over time. Both adults and immature bald eagles have yellow feet, and their legs are feathered halfway down.
Monumental Moment: In 1983, only three bald eagle nesting pairs remained in Pennsylvania. The Game Commission and several other Northeast states launched what would become a seven-year bald eagle restoration program. In this federal initiative, the Game Commission sent employees to Saskatchewan to obtain eaglets from wild nests. Other states drew from other capable wild eagle populations. Initially, 12 seven-week-old eaglets were taken from nests in Saskatchewan’s Churchill River valley and brought to two specially constructed towers in Pennsylvania. . . Find out where in the June issue of Pennsylvania Game News.
What makes an eagle, an eagle? Eagles are very large birds of prey and are grouped in the same family as hawks, the Accipitridae family. Like other members of this family, eagles have hooked beaks, curved talons and are most active during the day. However, with a wingspan of 6 to 8 feet, eagles are much larger than hawks. Bald eagles are often confused with turkey vultures and osprey, especially in flight. When looking up at a large bird of prey in flight, look for the turkey vulture’s two-toned underwings—dark with a pale gray color and the slight “V” shape to the outstretched wings. An Osprey has a dramatic white pattern on the underwings and an angular “M” shape to the wings. Eagles have dark wings and fly with their wings flat and horizontal, forming a straight line out from their body. Although, eagles are found throughout the world, the bald eagle can only be found in North America. Both the golden eagle and the bald eagle can be seen in Pennsylvania. The golden eagle migrates through Pennsylvania and may stay through the winter. The bald eagle is a resident bird and now nests throughout the state. Check out our Educator's Guide to Celebrating Pennsylvania Bald Eagle and Elk Reintroductions.
Double coverage: With some species of birds like mallards, black ducks, and many other puddle ducks, eggs and chick management is done solely by the female. Bald eagles and many other birds of prey and songbirds have the added advantage of both parents rearing the young. You will often see both adults feeding the voracious eaglets and protecting them from inclement weather. Even when we can't see them in the limited camera view, they always have a watchful eye on the nest.
The Flying Plank: Bald eagles fly with slow, powerful wing beats and soar with wings at right angles from the body. The bald eagle's flight profile is very flat – giving them the "flying plank" nickname. Bald eagles have a different profile than the golden eagle. In flight, the bald eagle's head and neck protrude half the length of the tail or more; a golden eagle's head protrudes less than half the length of the tail. The golden eagle's tail protrudes behind the bird about 3 times as much as the head protrudes in front. The bald eagle's massive bill also is a good field mark, yellow in adults.
Good day for a swim! On days like we have been having lately it seems like the eaglets have enough water in the nest to go for a swim. As juveniles, eagles cannot swim very well, but occasionally when the adults are hunting for fish, they glide in to grab one and it turns out to be too large for a swift grab-and-go. In some cases, the eagles keep a hold of their prey and manage to swim to shore where they eat or break down the fish in to moveable pieces.
Thanks Mom and Dad. I’ll eat it later! Eagles, like many other birds, have an organ in their digestive system called a crop. The crop allows them to eat lots of food very quickly and then store it in something like a “doggy bag” so they can digest it at a later time. They can take advantage of the opportunity to feed quickly. This is an important mechanism birds facing competition for food, like the two eagle chicks, or adult eagles needing to quickly devour as much of a prey item as possible to escape harassment from other animals. Learning at home? Check out this activity about bird digestive systems for grades 3-6.
Get a grip: The adult eagles walk with careful feet around the nest. However, when they are hunting, they have a pretty serious grasp on their prey sometimes referred to as grip strength. We're talking pounds per square inch or psi. Eagle grips have been recorded at 400 psi, great-horned owls at 300 psi, and red-tailed hawks at 200 psi. We humans sometimes think we have a pretty good grip. Here’s a way to do an unofficial grip strength test for yourself with some simple items you probably already have in the house. Take a bathroom scale, hold it up with both hands on the sides of it, so you can read the numbers in front of you. Squeeze the scale with as much strength as you can and record the number. Mine was about 90 pounds. Then take a ruler and get a measure of your square inches of your palm. Again, mine was about 3” x 4” or 12 square inches. Divide 90 into 12. Mine was about 7.5 square inches. What's yours?
Shiver, huddle, fluff: Along with downy feathers that help trap warm pockets of air close to a bird's body, the act of shivering, huddling close to their sibling and the adults, and fluffing up their feathers are what helps keep the young eaglets warm on rainy, cold days like today. The adult eagles not only have a good layer of downy feathers, they also have well-maintained contour feathers that, when preened (or groomed by their beaks), are virtually waterproof and windproof.
Eagle Eyes! Eagles use both monocular (looking out of one eye) and binocular (using both eyes) vision. Some people estimate that eagles can see something the size of a cottontail rabbit from a distance of 3 miles. Although the eagle's head is much smaller than an adult human's, an eagle's eyeballs are about the same size as a humans. Relatively, their eyeballs take up a lot more space inside their skull and eagles cannot move their eyeballs around. Eagle eyes are fixed in place and held by a boney circle called a sclerotic ring. An eagle must move its head to look around. Eagles can see in color, possibly even more colors than humans can see. Do you think they prefer trout brown or bunny brown?
Do birds get cold feet? Cornell's Bird Lab is a great resource for bird information! I found this today. "Birds also have a countercurrent heat exchange system in their legs and feet—the blood vessels going to and from the feet are very close together, so blood flowing back to the body is warmed by blood flowing to the feet. The newly cooled blood in the feet lowers heat loss from the feet, and the warmed blood flowing back into the body prevents the bird from becoming chilled. And because bird circulation is so fast, blood doesn’t remain in the feet long enough to freeze." https://www.allaboutbirds.org/news/why-dont-birds-get-cold-feet/
In 1998, Pennsylvania was home to 25 pairs of nesting bald eagles. Within the next three years, the number of nesting pairs doubled. By 2006, more than 100 nests were confirmed statewide. And the number of nests topped 250 in 2013, with bald eagles nesting in all but a handful of the state's counties. The nesting population continues to grow in size and expand in geographical range, and a lot of good habitat remains. Biologists believe the commonwealth is now home to more than 300 nesting pairs. Watch this 20-minute documentary on the reestablishment of Pennsylvania's bald eagle population. Spoiler: chicks were brought in from Saskatchewan!
Nesting eagles are sensitive to human intrusions and disturbances, but more eagles are nesting near communities and activity areas than ever before. Eagles may forage a mile or two from a nest, but tend to be very efficient hunters that do not wander far from good foraging opportunities. Though we are often unable to see adults in the camera view, it is very likely that they are not far off and keeping an eye on the nest.
Safety Goggles: Nictitating membranes are the thin, translucent fold of skin that sweeps across the eye sideways, from front to back, moistening and cleaning the eye and protecting the surface of birds' eyes. Click the link to check out this video of a great-horned owl's from Cornell's Bird Lab. https://www.facebook.com/cornellbirds/posts/ever-heard-of-a-nictitating-membrane-our-bird-cams-team-explains-this-fascinatin/1462326460479173/
Happy Friday all! Just a quiet reminder about why we carefully protect the location of the nest. An identified location is at risk of unsolicited human visitors and disturbance. We know you are passionate about the health and safety of this eagle family and we don't want anything to happen to them or to the landowners who generously allow us this opportunity. It would be a terrible shame to be forced to turn off the camera in an effort to protect the families here. Take care and please enjoy the view, while protecting it. Sincerely, pgc.
Eagles don't reach adulthood and begin breeding and nesting until age four or five and can live a long life for a bird, up to about 30 years. Bald eagles are known for their spectacular courtship, including acrobatic flight displays. The "cartwheel display" is perhaps the best known. In this courtship act, the pair flies to great altitude, lock their talons in flight, and tumble in cartwheels back toward the earth, breaking off their hold at last moment before colliding with the ground. These flight displays often occur in winter. In Pennsylvania, some pairs seem to occupy the same areas all year long, while others leave their nesting area when ice forms on the water and decreases their ability to find fish.
Hacking: As part of a federal restoration initiative, the Game Commission sent employees to the Canadian province of Saskatchewan to obtain eaglets from wild nests. From 1983 to 1989, 88 eaglets were brought to Pennsylvania, where they were raised in specially constructed towers and released into the wild through a process known as "hacking." Hacking is a falconers' term for maintaining a young bird in a semi-wild condition, providing food until it can fend for itself. Pennsylvania's reintroduction effort jump-started a remarkable recovery. Watch this 20-minute documentary on the reintroduction to Pennsylvania. https://www.youtube.com/watch?v=-4DK0sCiMd8
No rest for the weary: If you take the time to watch the live cam at night, you will see the adults hovering over their sleeping chicks and gently preening them with their powerful beaks. You might think it would be easy for them to catch some shut-eye when the chicks are sleeping but it seems that even at night the adults are working the night shift.
Good parent, keeping the kiddos and the surrounding area warm and dry by covering the eaglets and nest bowl with its body and wings during the wet, stormy weather. Nature definitely has endurance! Anyone else warm and dry #STAYHOME #STAYSAFE parenting today?
Factors affecting nest success: Bald eagle nests and young eagles are easily disturbed and nest failure can occur when people get too close to an active nesting area. Adults might abandon a nest site altogether or leave eggs or hatchlings exposed to sun, cold temperatures, severe weather, and predators. Also, when growing eaglets are disturbed before their first flight, they may fledge prematurely, and become vulnerable to terrestrial predators and inclement weather. To protect eagles, people should keep their distance from active nests, roost sites and feeding areas, and avoid approaching a nest directly. Federal regulations prohibit any intrusion within 660 feet of the nest.
Fascinating beaks: Birds have many adaptations, their beaks come in different sizes and shapes. Woodcock have a thin, long pointed bill that helps them probe the soft earth in search of worms. Cardinals have a short thick bill that is great for cracking seeds. Some dabbler-type ducks, like the mallard, have a wide flat bill with serrated edges that help them filter small aquatic plants in the marshes and shallow water habitats that they like to feed in. The bald eagle on the other hand, has a very thick, curved and sharp beak used to kill prey, tear off pieces of meat, and feed those pieces to their eaglets. The fact that this very large bird can remove a piece of food that is about the size of a nickel and then maneuver it into the waiting chick’s mouth is a fascinating adaptation.
Second lunch anyone? The eaglets are really growing fast at this point in their development. If you have been watching the live stream, but maybe missed a day or two, as soon as you tune in you won’t believe how quickly they are progressing. According to the American Eagle Foundation, eaglets can put on a half-pound to a pound of body weight every week until they are about 9 or 10 weeks old. That’s some serious weight gain. Anybody for second lunch?
White washed: While watching the live stream you will notice many of the branches have fecal waste deposited by the eagles on them. The color seems to last a long time even after a rain event. There's a reason for this. Birds don't poop like most other animals and they don't produce a urine like most animals either. Instead, they secrete waste which is filled with nitrogen in the form of uric acid, which emerges as a white paste or white wash as it is sometimes called. Uric acid doesn't dissolve in water real well, so the tree branches stay white, kind of like funky wallpaper.
Opportunistic feeders: Bald eagles are notorious for their ability to pirate fish from other piscivorous (fish-eating) birds like ospreys and common mergansers, chasing the other bird until it drops the fish. Bald eagles are very efficient foragers that are conservative in their energy expenditure. Although bald eagles will hunt in flight and by wading in water for prey, they generally perch on a tree or snag and wait for their prey to appear. They are opportunistic foragers and take whatever is available, but generally consume fish. Bald eagles also will scavenge dead fish, waterfowl and mammal carcasses, including large herbivores such as deer and livestock. Mammals, birds, and carcasses become a more important part of their diet in winter when fish can be more difficult to find and reach because of water levels or ice-cover.
Emerging feathers: These two eaglets hatched out on March 25 and 27. They are about a 1-1.5 weeks old. Flight feathers emerge in two to three weeks and body contour feathers emerge along the upper wing in three to four weeks. Eaglets gain a lot of weight daily with a maximum average gain of 102 grams per day and 130 grams per day by males and females, respectively. They achieve maximum growth in three to four weeks.
Awesome eyes: Adult eagles have a very intense looking set of eyes. Their eyes are very large in relation to the size of their skulls. Animals with large eyes, noses, or ears rely heavily on this adaptation to survive. Eagles have eyesight that is five to six times greater than humans. This awesome eyesight enables them to see prey from hundreds if not thousands of feet away while they are soaring or perching.
Housekeeping: Throughout the day, the adults can be observed "housekeeping" at the nest. They take individual grasses and twigs and move them from one location to another. In some instances, they can be seen moving food items. It doesn’t seem like it accomplishes much but it might be an example of keeping the nest clean, warm, and safe for the eaglets. The eagle family is kind of stuck at home, like most of us are currently. Are you spending time cleaning your nests in between eagle check-ins? #COVID19 #WeAreInThisTogether
The resident eaglets made their way out of eggs on March 25 and 27, making the first a week old today. Because eggs hatch over several days, age and size differences among hatchlings often gives the first hatchling a head start and a competitive advantage at feeding time. A large, healthy eaglet might kill a smaller, weaker one or out-compete it for food. We can look forward to the eaglets developing most of their feathers during the next 2 to 3 weeks. Learn more in this Wildlife Note.
Shredded vittles: Eagles feed their young by shredding pieces of meat from birds and mammals or fish flesh with their beaks. The adults gently coax their tiny chicks into taking a morsel from their beaks. They will offer food again and again, eating rejected morsels themselves and then tearing off another piece for the eaglets.
Careful steps: Watch closely to see the adult eagles carefully ball up their talons while walking near the eaglets to avoid accidentally stepping on them and causing injury. After they take turns feeding them, one of the
adults will cradle them under their bodies and use their wings to grasp the
chicks and keep them close to their bodies for protection and warmth.
Protective wings: Throughout the day, the adult eagles take turns feeding and then resting over the chicks, keeping them warm and dry. Many times one of the adults will leave the nest, soaring and stretching their wings, and hunting. Their wings are huge, with a span of six to eight feet when spread. Each wing is made up of thousands of feathers, all designed to make the eagle aerodynamic when flying and keep the eagle warm and dry on rainy or snowy days. They also use those big wings to shelter the young chicks and hide them from predators. Check out a this cool, self-guided activity you can do at home and learn more about bird wings.
Parents at home with a printer, check out this activity! Let’s wing it! (PDF) Let's wing it! Parent/Educator Guide (PDF)
What do they eat?
Fish, either caught live or scavenged as carrion, make up 60 to 90 percent of a bald eagle's diet. Bald eagles also eat birds, small mammals, reptiles, amphibians and invertebrates. Eagles soar above the water or sit on a perch, and when they spot a fish near the water's surface, they swoop down and snatch it in their talons. They use their talons for killing, and their heavy bills for tearing prey apart for eating. Sometimes an eagle will go after an osprey or another fish-eating bird, forcing it to drop a captured fish, which the eagle grabs in midair. This behavior is known as "pirating" prey. Learn more in the Pennsylvania Game Commission's Wildlife Note: https://www.pgc.pa.gov/Education/WildlifeNotesIndex/Pages/EaglesOsprey.aspx
A second eaglet makes its appearance. Both adults are regularly seen feeding the siblings. The siblings do pick on each other, this is not unusual behavior. In extreme circumstances, one sibling could kill another. Food items have included: fish, muskrat, squirrel, and small birds and mammals.
One of the adults moves an egg out of the nest, presumably because there was something wrong with it. That egg did not hatch.
The first eaglet to arrive is seen early in the morning.
March 23 - LIVE Chat
Pennsylvania Game Commission's State Ornithologist Sean Murphy and Endangered Bird Specialist Patti Barber joined us LIVE in the chat feature to answer your questions.
Do you know what percentage of eagles migrate north to Canada during breeding season? Is that percentage going up now with territorial competition. Bald eagles migrate thru Pennsylvania all months of the year. Pennsylvania birds breed January thru July. Eagles are moving thru the flyway constantly, without population-specific data, it would be difficult to know.
Do they typically lay more than one egg? Birds at this nest have historically raised three young. Good habitat and good parents. During the reintroduction of bald eagles to Pennsylvania, the smallest nestlings from nests in Canada where brought back to Pennsylvania and raised. You can watch the 20-minuted documentary here: https://www.youtube.com/watch?v=-4DK0sCiMd8
Do you believe in the theory that some bald eagles are smart enough to not set right away on the first egg to delay hatching and if so why do you think only so few practice it? Biologists believe it isn't really problem solving, it is evolutionary pressure for survival that leads to asynchronous hatching. This way they raise more young in the long run
How old are they? With neither adult banded, it would be nearly impossible to tell how they are. There has been an active nest in the area for 15 years.
Do the adults know when the eggs will hatch? Adult birds can hear the chicks in the eggs while they’re pipping. You can sometimes see the adults inspecting the eggs just before they hatch. They may be able to feel the movements too, but I don’t know of anyone that’s tried to measure that. Pretty cool!
Why can't I keep a feather from a bald eagle or song bird? It’s for the birds’ protection. If you have feathers there so way to tell if you found and picked them up after the bird mounted or if you killed the bird to pluck them. By making it illegal to have them it keeps people from killing the birds to get the feathers them claiming the birds dropped them naturally.
The first egg was left alone for three hours with very cold temps the night it was laid due to a disturbance at the nest, do you think that will have any effect on it hatching? There are many examples of low temperatures not being a problem before incubation starts. Even if all three eggs don't hatch, we won't really know which didn't or why.
Do they mate for life? Once a pair is successful raising young, they tend to stay together until something happens to one of them.
Are bald eagles the biggest bird in North America? The California condor is even bigger.
How fast are they? They have been recorded at speeds between 36 and 44 miles per hour. Peregrine falcons can fly much faster.
Is the eagle bigger than my couch? Depends on your couch. Their wingspan could be 8 feet long. The nest might be the size of your couch.
If an egg is nonviable why will they continue to incubate it? They can easily incubate the first egg while they continue to incubate the second and third. The energy investment of incubating a nonviable egg is much less than that of no longer incubating a viable egg.
How long until they hatch? Incubation is generally reported at about 35 days. The first egg is on day 39 at this point, so we'll just wait to see how many hatch.
What are their names? The Latin name is Haliaeetus leucocethalus. We prefer not to name them and encourage folks to think of them like pets. Rather we respect their wild nature and don't offer pet names.
How many times to they molt? All bald eagles have an annual molt that begins in late spring and is completed by late fall.
How many bald eagles are in Pennsylvania? Since removing bald eagles from the state threatened and endangered list in 2014, we haven't done a full survey. We are comfortable in saying that there are more than 300 active nests in the state though we don't have an actual count. You can help us learn about active nests by reporting any nests you see by the completing the survey found on our Bald Eagle webpage: https://www.pgc.pa.gov/Wildlife/WildlifeSpecies/BaldEagles/Pages/default.aspx
Does anyone keep track of all the bald eagle nests in Pennsylvania? You can help us document location by filling out the survey found on our Bald Eagle webpage: https://www.pgc.pa.gov/Wildlife/WildlifeSpecies/BaldEagles/Pages/default.aspx
Why do they do the mombrella pose on the nest? It is important to keep the nest area dry when it is raining or snowing to maintain appropriate temperature for eggs and nestlings.
Why does the beak look broken? It isn't broken. No cause for worry. It's just debris, perhaps from a prior meal or nesting material.
How did you get the camera in the tree? Very carefully! Long before the birds were there regularly, with a bucket lift and the expertise of the folks at 🔸HDOnTap 🔸
Do both the male and female lay eggs? No, only the female lays eggs.
What is their favorite food? Fish. They also eat small birds, mammals and reptiles. They are opportunistic feeders and great scavengers also. At this nest we sometimes see chickens as prey items, they are very resourceful.
Do they all have the same color eyes? Juveniles will have brown eyes, which lighten as the bird ages to white or light yellow.
How big is an eagle? About 6.6 to 14 pounds. The wingspan can be up to 8 feet across.
Are there layers in the nest? The base construction is done with larger sticks, lining of the nest is finer softer material that provide the smooth platform of the bowl.
I've seen other nests where the older siblings pick on the younger ones. Sometimes all don't survive. Yes, siblicide does happen.
Will all the eggs hatch? Chances are good based on the history at this location.
How can you tell the male and female apart? Generally the female is larger than the male. However with a camera angle like this, the bird closest to the camera often looks largest.
How big is an eagle nest? This nest is pretty large, 4 or 5 feet across and another 4 or 5 feet deep. They've been recorded up to 10 to 20 feet across. One 34 year old nest weighed almost 2 tons.
I'm a teacher, where can I find resources for my students and curriculum? Check out this page on our website, scroll down for resources that might be excellent for this purpose. https://www.pgc.pa.gov/Education/ForEducators/Pages/default.aspx
Is it hard for the adults to sit on the nest in the rain? I wouldn't say hard, but it takes some persistence. If you look closely near the shoulder of the bird, you can see how the rain beads up and rolls off because of the waterproofing oils on the feathers.
Do the babies move around inside the egg? Yes they do. The hatching process depends on that. The egg rolling by the adults during incubation assures that the eaglet is develops properly.
Do bald eagles reuse the same nest? Yes, they often do.
Do both male and female bald eagles incubate the eggs? Yes, though the female seems to do the bulk of it.
How long with the young eagles interact with the adults? They could fledge the nest from 8 to 14 weeks after hatch and then could hang around with other nestmates and adults another 4 to 10 weeks. There is quite a bit of variability in individuals depending on the general health and independence of the juveniles.
#PipWatch! If all has gone well, the eggs should begin hatching very soon. Young birds (eaglets) are fed by their parents. Because eggs hatch over several days, age and size differences among hatchlings often gives the first hatchling a head start and a competitive advantage at feeding time. Let us know if you see an egg that looks like it has a small hole in it. That could be the first eaglet getting ready to make its appearance!
A Warm Breeze "When it’s hot, some species will also resort to gular fluttering. The bird will open its mouth and “flutter” its neck muscles, promoting heat loss (think of it as the avian version of panting)." - Audubon.org Join us Monday at 1pm to chat LIVE with the Pennsylvania Game Commission's State Ornithologist Sean Murphy and Endangered Bird Specialist Patti Barber to have your questions answered. We hope you'll be here!
What feathers do (from the Cornell Bird Lab)
"The feathers keep the plumage waterproof. Their interlocking microstructure creates a barrier that allows water to roll right off the bird's back. Birds constantly maintain their waterproof coat through extensive grooming, or preening, to ensure that every feather is in good shape. The interlocking structure is so important that any disruption to it—such as if spilled oil coats the feathers—leaves the bird waterlogged and helpless." https://academy.allaboutbirds.org/features/all-about-feathers/#what-feathers-do.php
Pairs bonds tend to last more than one year, but although bald eagles are generally believed to generally bond for life, this is poorly studied because of the difficulties in capturing and marking each bird. (Pennsylvania's population is largely unmarked.) The persistence of pairs at sites from year to year, sometimes for decades, suggests long-term pair bonds. However, it is possible that pair bonds can break up after nesting failures. When one of the pair dies, the remaining eagle often seems to find a mate and retains the same territory.
The success of bald eagles in Pennsylvania is directly related to improvements in environmental quality; eagles are dependent on good water and riparian forest quality and subsequent fish availability. The bald eagle's recovery is a victory for the Endangered Species Act and much more. Learn more.
If all has gone well, eggs could start hatching around the 19th. Let us know if you see anything "egg"citing!
Bald eagles are very efficient foragers that are conservative in their energy expenditure. Although bald eagles will hunt in flight and by wading in water for prey, they generally perch and wait for their prey to appear. They are opportunistic foragers and take whatever is available, but generally consume fish. Bald eagles also will scavenge dead fish, birds, and mammal carcasses, including large herbivores such as deer and livestock. Mammals, birds, and carcasses become a more important part of their diet in winter when fish can be more difficult to find and reach because of water levels or ice-cover.
A bald eagle's large, sharp talons are capable of dispatching large prey items. Unlike the golden eagle, which is a "booted" eagle, the tarsi of the bald eagle are not feathered. The bald eagle is considered a member of the fish eagle or sea eagle group that includes large eagles such as Steller's sea eagle (Haliaeetus pelagicus) of northwestern Asia and the white-tailed eagle (H. albicolla) of Eurasia. Learn more.
1. Feb. 13; 4:24p
2. Feb. 16; 2:31p
3. Feb. 19; 3:03p
Due to hatch: If all goes well, we can expect eggs to start hatching 35-38 days after being laid.
1. March 19-22
2. March 22-25
3. March 25-28
Bald Eagle Fast Facts
Bald eagles build the largest nest of any North American bird.
The wingspan of a bald eagle ranges from 5.5 to 8 feet.
Bald eagles are 28 to 40 inches in length.
An eagle may weigh 8 to 12 pounds.
Female eagles can be 25 percent larger than male eagles.
Both males and females will sit on the nest to protect the eggs or young, foraging for food or perching nearby when not at the nest.
Bald eagle egg incubation
Incubation begins as the female lays the first egg. The clutch of one to three eggs is typically completed within three to six days. Both parents share in the task of incubating. However, females spend more time brooding than males. During incubation, we will typically see only one eagle at a time, except when they make the incubation duty changeover. When an exchange takes place at this nest, viewers often make a note of the time in the chat below the live stream. Learn more about bald eagle nesting.
What's happening inside those eggs?
Check out this neat animation from The Cornell Bird Lab. Bald eagles start incubating with the first egg, unlike some bird species that wait until they have a full clutch of eggs before they start incubating. That means the egg laid on February 13 is several days more developed than the egg laid yesterday, on the 19th. Enjoy! https://academy.allaboutbirds.org/egg-animation-withtext_500h/
At what age do bald eagles breed?
Eagles do not breed until 4 or 5 years of age. Good water quality, riparian forests, and wetland habitats are vital for Pennsylvania's breeding eagles. As the population increases and optimal nesting locations fill up, we may start to see increased competition for prime locations. Learn more in our Eagles & Osprey Wildlife Note.
Bald eagles normally produce one to three young per year. One pair in Northampton County produced a record four young in 2009. If all goes well, the eggs begin hatching after about 35 days.
First egg: Thursday, Feb. 13; 4:24p
Second egg: Sunday, Feb. 16; 2:31p
Will there be a third? The eagles nesting in this area have successfully reared three young most years.
First egg Thursday, February 13: 4:24p.
Bald eagles generally have a clutch of one to three eggs with two the most common clutch size. One egg is laid per day, but not always in successive days, with the clutch completed in three to six days. Keep your eyes online Saturday afternoon, could be another big day for eagles in Pennsylvania.
Adults visited between 7-8a, 9-9:30, briefly at 10:20 and 12:15, and then hung around the nest between 3:45 and 5:45p.
What do 100,000 snow geese sound like?
If you haven't checked out the Snow Goose Cam from the Game Commission's Middle Creek Wildlife Management Area, now is good time! Snow goose numbers are highest during mid-afternoon, dusk and dawn. This morning there were an estimated 75,000 snow geese at the lake.
Adults visited the nest briefly on this damp, rainy day around 6:30a, 8:45, 9:50, and 1:20p.
Have you seen a bald eagle nest in Pennsylvania?
Complete the Bald eagle nest survey online. The incredible recovery of bald eagles means we need your help with monitoring them. Please let us know about the nests you see. By adding together everyone’s observations we can better identify all the new nests and track eagle productivity in the state. https://pgcdatacollection.pa.gov/baldeaglenestsurvey
It was a rainy day. Adult made many quick visits throughout the day between 6:30a and 4:30p and took time to grab a quick bite of chicken (perhaps).
The time-lapse feature reveals that adults visited the nest between 6:45-7:30a; briefly around 8, 8:30, 9:15, 10, 10:45, 5:30, and 5:45; and for longer visits between 2-3p and 6:30-7:45p.
#eggwatch - Let us know if you catch an egg appearance by noting the date and time.
Eagles will lay eggs in February through April, sometimes sitting on eggs when there is ice and snow on the ground. This is one of the reasons why it is not good to approach nests too closely. If you flush an adult off of a nest in the incubation period you can expose the eggs to cold air, causing nest failure. The rain is supposed to continue through Friday. Learn more at: https://www.pgc.pa.gov/Wildlife/WildlifeSpecies/BaldEagles/Pages/FromTheNest.aspx
Adults visited briefly in the morning and again in the afternoon on this blustery, rainy day.
Good environmental quality is good for bald eagle population
The bald eagle recovery was fueled by the Game Commission's eagle reintroduction program from 1983-89. Conditions were right for the project because population limitations including the harmful effects of pesticides on eagle reproduction, poor stream water quality, the lack of trees along many streams, and, in some cases, direct persecution had subsided by that time. The success of bald eagles in Pennsylvania is directly related to improvements in environmental quality; eagles are dependent on good water and riparian forest quality and subsequent fish availability. The bald eagle's recovery is a victory for the Endangered Species Act and much more. Watch this 22-minute documentary of the Game Commission's reintroduction efforts.
Adults visited the nest briefly at 7a, 7:30, 7:45, 8:45, and 10:30 with food (possibly a fish). Then hung out for about an hour between 1 and 2p and stopped briefly at 3:30 and 5p.
What's a brood patch?
Definition per Merriam-Webster: a featherless, fluid-filled area on the abdomen or breast of birds that is filled with surface blood vessels which are used to apply heat to the eggs during incubation. Both female and male eagles incubate eggs in their nest, though the female does the bulk of it. Both will have a brood patch, though the female's will be more substantial. Let us know if you see one!
The time-lapse video indicates the unfamiliar visitor spent quite a bit of time at the nest between 3:15a and 8:30a. Resident birds were spotted at the nest around 8:35a; 9:30-10:15; 11-11:30; 1:00p; 1:30-2:30; 4:55; and between 5:30 and 7:15 in the evening.
Floaters and Breeding Vacancies
Quick recap, a strange adult appeared at the nest yesterday and this morning (2/4 and 2/5), and spent quite a bit of time there. Some interactions with what appeared to be the resident birds seemed subordinate while others seemed aggressive. One of our biologists describes this as a "floater" looking for a breeding vacancy. When one of a pair is lost, a floater can quickly replace them. Both resident birds were back in the nest together around 10a.
Per the time-lapse: brief visits at 9:09a and 5:30p. A stranger spend quite a bit of time at the nest between 11:20a and 1:40p, and again between 2 and 2:30p.
No Longer Endangered
The bald eagle was removed from the federal Endangered Species list in 2007. Its Pennsylvania status was changed to Protected in January 2014 based on data from 2008 to 2013. Criteria for removing the bald eagle from the state's threatened species list were laid out in the Game Commission's bald eagle management plan. The plan called for delisting eagles if four criteria were met for five consecutive years. There had to be at least 150 active nests statewide, successful pairs in at least 40 counties, at least a 60 percent success rate for known nests, and productivity of at least 1.2 eaglets fledged per successful nest. In 2008 through 2013 Pennsylvania's bald eagles exceeded all of these criteria with 171 to 274 known nests, in 46 to 58 counties, with success rates of 74 to 92 percent for known nests, and productivity of 1.3 to 1.8 eaglets fledged per successful nest. Learn more.
The angle of the winter sun is causing some spectacular colors at the nest at sunrise and sunset. Time-lapse view shows adults visited the nest several times. The longest visits lasted about an hour each between 9:30-10:30 and 1:15-2:15. Shorter visits took place at 6:15a, 7:15, 8:30, 8:55, 12:15, 4:20, 4:55, and 5:30.
Factors affecting nest success
Factors affecting nest success are many. Bald eagle nests and young eagles are easily disturbed and nest failure can occur when people get too close to an active nesting area. Adults might abandon a nest site altogether or leave eggs or hatchlings exposed to sun, cold temperatures, severe weather and predators. Also, when growing eaglets are disturbed before their first flight, they may fledge prematurely which makes them vulnerable to terrestrial predators and inclement weather. Review this Bald Eagle Nest Etiquette.
Adults visited the nest between 6:50-7:00; 10:50-11:10; 1:35-2:30; 4:15-5:20; and a quick stop around 5:30. Some sort of bird was brought to the nest as a food item, today.
How big are they?
Adult bald eagles are 30 to 40 inches in length and weigh 8 to 14 pounds. Their wingspans are 6 to 8 feet, and they stand about 2 feet tall. As with other birds of prey, the female is typically larger than the male. Learn more in Wildlife Note on eagles and osprey.
Adults continue to frequent the nest, bringing new nest materials like sticks for the bulk of the nest and softer grasses for the nest bowl. Visits occurred during these time frames: 7:30-8, 9:50-10:15, 11:30-11:45, 12:20-1:30, and 2:50-3:30.
Adults visited between 7-7:15, 8-8:30, 9-11:15, and 12-1:30.
In reviewing the time-lapse footage from yesterday, there was a songbird that sheltered in the nest Sunday night.
Adults visited on and off between 7:45 and 9:45a, for a brief visit around 12:45p, and lastly between 3:30 and 5:30p.
Adults visited the nest between 8:50-9:55a; and again between 10 and 11a.
Adults visited the nest on and off between 8 and 9:45a; at 11:45; and when the juvenile bird stopped by between 1:15-2p.
Changes in Plumage
A bird stopped by earlier today that had dark markings on its whitish head and tail, along with light markings on its dark back. It was likely a younger bird; perhaps an offspring of the nest. The mature eagle's head is covered with gleaming white feathers. Its body is dark brown, its tail white. Immatures are brown, mottled with white on their wings and body. Full adult plumage is attained in the fifth year. Both adults and immature bald eagles have yellow bills and feet, and their legs are feathered halfway down. Read more in the Eagle Wildlife Note. It appeared that the resident birds were relatively tolerant of the visitor.
Adults seems to be hanging out at the nest more often these days. Today: between 8:45 and 9:45; 10:45-11:45; 1:30-3:30; and 5-5:30.
A bald eagle's call is a rapid, harsh cackle, kweek-kik-ik-ik-ik-ik, or a lower kak-kokkak.
The Cornell Lab explains the difference between a bird song and bird call: Why are some bird sounds referred to as songs and others as calls? Typically a song is defined as a relatively structured vocalization produced while attracting a mate or defending a territory. Calls tend to be shorter, less rhythmic sounds used to communicate a nearby threat or an individual’s location. Each species and individual has a variety of songs and calls used in different contexts that together make up its repertoire. https://academy.allaboutbirds.org/birdsong/
Adults at the nest this morning and again throughout the afternoon.
How long does it take to make an egg?
Sperm can be stored in the female eagle's oviduct for long periods. Bald eagles in Pennsylvania typically lay eggs between mid-February and March. Average clutch size is two eggs, which are laid at least a day apart. The Cornell Lab states, "When an ovum is released into the oviduct and fertilized, it is just a protein-packed yolk. The albumen—the gelatinous egg white—is added next. The blobby mass then gets plumped up with water and encased in soft, stretchy membrane layers. The first globs of the calcium carbonate shell are then deposited on the exterior, with the mineral squirting from special cells lining the shell gland (uterus). Pigmentation, if any, comes next, with an overall protein coating added before the egg is laid. It takes about 24 hours to build a single egg." Learn more: https://www.allaboutbirds.org/news/the-beauty-and-biology-of-egg-color/
Adults seen visiting the nest in the mornings and late afternoons.
Strong winds continue this morning. One adult visited the nest around 11a. and appeared to eat a fish. Two adults continued to drop by throughout the day and stopped by in the evening, after the winds settled down, to eat what may have been a chicken.
Very windy out there today. Two adults visited on several occasions between 7a. and 4:30p.
Adults seen at the nest for brief visits throughout the day.
The exact reasons for the bald eagle’s spectacular acrobatic “cartwheel flight” remains unclear. Studies have identified the behaviors as one of many of courtship behaviors. Other behaviors include vocalizations and additional flight maneuvers such as the “chase display”, in which paired individuals will pursue each other, occasionally lock talons, roll, and dive; and so-called “roller-coaster flight”, in which eagle will fly to great altitude, fold wings, and dive directly to earth, swooping back up at the last instance to avoid collision with the ground (Stalmaster 1987 – The Bald Eagle). These incredible behaviors are likely strategies for mate selection and pair bonding. It is worth noting that eagles may displays these behaviors during the nonbreeding season antagonistically, but more often the flights are a sign of the forthcoming nesting season.
Two adults seen at the nest throughout the day before the rain set in.
A Full Crop
The crop is used to store food. After a good meal, you may be able to see a bulge in the chest of the bird, signifying its full crop. We "flew" over to The Cornell Lab to learn a little more. https://academy.allaboutbirds.org/features/birdanatomy/
Power was out for a short bit this morning; we had some heavy wind over the weekend. Two adults have been seen at the nest for long visits in the morning and again in the afternoon.
Two eagles in flight. Dave C. caught this scene on the Middle Creek Snow Goose cam.
Bald eagles are known for their spectacular courtship, including acrobatic flight displays. The "cartwheel display" is perhaps the best known. In this courtship act, the pair flies to great altitude, lock their talons in flight, and tumble in cartwheels back toward the earth, breaking off their hold at last moment before colliding with the ground. These flight displays often occur in winter, giving support to the idea that many pairs remain bonded through the year. In Pennsylvania, some pairs seem to occupy the same areas all year long, while others leave their nesting area when ice forms on the water and decreases their ability to find fish. The snow goose migration is coming up.
Adults were seen bringing in new nest material shortly after 9a. and again between noon and 3p.
Also, a Cooper's hawk was spotted again at the nest. Watch the clip.
The rattling call of a kingfisher has been heard a few times today, too.
No sightings on this snowy day.
Bald eagles typically reuse a nest and may continue to build at more than one nest at a time. Sometimes a nest gets so large that it falls; having a backup comes in handy at that point. The nest has a very limited purpose, much different than a human home. It isn't the place bald eagles loaf or spend the night unless there are eggs or young. If there are eggs, they typically won't be left unattended very long and will be incubated overnight.
Pennsylvania's winter bald eagles: southern & northern
Although we tend to focus on the nesting population of bald eagles, many eagles migrate through the state or spend the winter here. The migration population can be divided into two parts: eagles that nest in the southern United States that migrate north after nesting season in winter to spend time in the northern part of their range, including Pennsylvania; and northern eagles that migrate from Canada and northern states through Pennsylvania to the south and return north each spring to their nesting grounds. Learn more.
Adults spotted bringing nesting material to the nest and visiting off and on throughout the morning.
European Starling (Sturnus vulgaris) —Starlings often stop by when the eagles are away. Starlings eat almost equal amounts of animal and plant food, including beetles, grasshoppers, ants, flies, caterpillars (gypsy moth and tent caterpillars are frequent prey), earthworms, grains, cherries and mulberries. When foraging on lawns in winter, starlings are usually gaping, probing their bills into the soil and prying apart grass roots to uncover beetle larvae. Starlings begin defending nest cavities in late winter, pre-empting them before native cavity-nesters start claiming territories. Starlings nest in woodpecker holes, crevices in trees and buildings, and bird houses. Learn more in this Wildlife Note.
The recovery of the bald eagle (Haliaeetus leucocephalus) has been one of the great wildlife conservation stories in the history of both the state and the nation. Pennsylvania's nesting bald eagle population has increased steadily and dramatically in recent years. As recently as 1980, the state's known nesting population numbered only three pairs. In 1990, there were eight active nests, 48 in 2000, and by 2006 the number cleared 100 for the first time since DDT decimated Pennsylvania's nesting bald eagle population in the 1950s and '60s. The increases continued into 2008 when the state's nesting eagles numbered more than 150 pairs, more than 200 pairs in 2011, and more than 270 pairs in 2013. The exponential increase in Pennsylvania's nesting bald eagle population is part of a regional increase and similar increases are taking place in Chesapeake Bay and New York populations. Learn more about their status in Pennsylvania.
What does a bald eagle sound like?
Bald eagle calls, courtesy of the Cornell Lab of Ornithology: https://www.allaboutbirds.org/guide/Bald_Eagle/sounds.
Adults stopped by briefly around 7a and again around 9:30a, 3:30p, and 4:45p.
Identifying individual birds - A word of caution.
As a rule, female birds of prey tend to be larger than their male counterparts. That being said, there is overlap and in some pairs, a male may be larger than the female. When it comes to markings on feathers and beaks, both change over time. Keratin makes up bird feathers and bills. As the outer keratin wears down, birds molt new keratin layers. This means that flaking on the bill or an oddly colored feather will eventually be replaced.
Adults visited the nest several times between 7a and noon.
Adults hung around the nest between noon and 3p, then stopped by briefly around 5p.
Dave C. caught this screen shot this morning.
Cooper’s hawk (Accipiter cooperii) — Length, 14 to 20 inches; wingspread, 27 to 36 inches; weight, 10 to 20 ounces (slightly smaller than a crow). Adults look like large sharp-shinned hawks — red eyes, blue-gray back and a rusty breast, except the Cooper’s has a rounded tail and the sharp-shinned hawk has a square-tipped tail. Named in 1828 after William Cooper, a New York naturalist, Cooper’s hawks prey mainly on birds the size of robins and jays. While hunting, they prefer to perch and wait for prey. Favored habitat is woodland. Cooper’s hawks breed throughout most of the eastern United States; they nest in trees 20 to 60 feet up. Eggs: 4 to 5, white, incubated by both sexes but mainly by the female for about one month. Woods where Cooper’s hawks nest may remain heavily populated with songbirds, as these hawks hunt away from their nest area. Call is similar to that of the sharp-shinned. Learn more in our Raptors Wildlife Note.
20 minutes to learn about the reintroduction of bald eagles in Pennsylvania
In the not so distant past, direct persecution and environmental contaminants drove eagle populations to catastrophically low levels. Protection at both state and federal levels, tremendous conservation efforts and improved waterway quality enabled them to rebound. In 1983, there were a mere three nests left in Pennsylvania. With the help of the Canadian government, the Pennsylvania Game Commission, and several other states reintroduced bald eagle chicks from Canada back to the Northeast United States. Today, Pennsylvania boasts more than 300 nests. This 22-minute documentary tells the story of that success. https://www.youtube.com/watch?v=-4DK0sCiMd8
Two adults coming and going between 7:15-9:00a and again between 10:40-11:30a.
Both adults at the nest this morning between 11a and 1p.
Both adults at the nest 12:45p.
Unique to birds and their dinosaur ancestors, feathers have evolved into impressive biological structures that come in a surprising diversity of colors and forms. The interlocking Velcro-like structure on many bird feathers creates the smooth, flexible, and resilient surface that supports flight and sheds water. - Cornell Lab of Ornithology: https://academy.allaboutbirds.org/feathers-article/
Both adults working on the nest on this nice morning, around 11a. and again at 1:30p.
Bald is a misnomer
The bald eagle's scientific name, Haliaeetus leucocephalus, means "white-headed sea eagle." The word "bald" is a misnomer. The mature eagle's head is covered with gleaming white feathers. Its body is dark brown, its tail white. Immatures are brown, mottled with white on their wings and body.
Both adults at the nest 9:15a.
Eagles and Osprey
Large, striking and charismatic birds of prey, the bald eagle, golden eagle and osprey embody power and majesty. All regularly occur in Pennsylvania, but only the bald eagle and osprey nest here. The golden eagle migrates through the state on a pathway connecting its breeding and wintering territories.
Both adults spotted at the nest shortly after 10a.
How big is an eagle nest?
A new nest is about 5 feet wide and 2 feet high, with an inside depression 4 to 5 inches deep and 20 inches in diameter. Often a pair returns to the same nest year after year, repairing damage and adding a new layer of sticks, branches and cornstalks, plus a lining of grass, moss, twigs and weeds. Enlarged annually, some nests grow so big and heavy that they break the branches or tree supporting them. Learn more in this Wildlife Note.
Both adults spotted at the nest around noon.
When does a bald eagle's head turn white?
The mature eagle's head is covered with gleaming white feathers. Its body is dark brown, its tail white. Immatures are brown, mottled with white on their wings and body. Full adult plumage is attained by the fifth year. Both adults and immature bald eagles have yellow bills and feet, and their legs are feathered halfway down. Learn more in this Wildlife Note.
Where is this nest?
In an effort to protect the privacy of the birds and the landowners who are graciously allowing us this viewing opportunity, we will not be disclosing information about the nest location and implore viewers to do the same. Thank you all for joining us to learn about Pennsylvania bald eagles.
The livestream opened shortly after noon on December 18, 2019 and the two adults made their debut around 2p that afternoon. Thanks for tuning in!
Starlings often stop by the nest when the eagles are away. Here is some Startling Starling information. From 100 birds released in the 1890s in New York City’s Central Park have descended more than 200 million starlings populating North America today. Starlings feed in flocks and roost together at night. In late summer and fall, their roosts may contain thousands of birds. Some individuals shift southward for the winter, while others remain in the Northeast; many roost in cities, where buildings give off heat, and then fly out into the surrounding agricultural land to feed during the day. Learn more in our Wildlife Note.