A Bald Eagle threesome, really?

Before I get to the main topic of today, I want to bring you an update on E17 and 18. You might have been wondering whether or not these little cutie pies would be leaving the clinic and going home to Harriet and M15 today. Sadly, it looks like the answer is no. It is no surprise that both of them are eating well. At today’s weight in and vet check, E17 was 445 grams and E18 was 340 grams. Oh, they sure are growing!

One thing that has happened is that E17 is showing aggression towards E18 during the feeding times yesterday, 3 February. This is about resources and is hardwired into raptors despite the presence of a full pantry from mom and dad. The staff of CROW can separate them but when they are returned to the nest the aggression will continue in the form of E17 bonking and E18 lowering its head in submission. This is natural behaviour. Do I like it? No. What I have observed is that the one being picked on gets really smart and sneaking in terms of getting its fair share. Old timers who have watched eagles for years tell me just to settle down, quit worrying, and ride it out. In the case of these two all will be well.

Harriet cannot separate them at the nest but CROW did. E17 is having a time out from bopping E18! Look at it having to sit in the corner.

Oh, gosh, these two are soooooooo cute.

Oh, gosh, they are just too cute for words. Image courtesy of CROW.

And here is the photo from this morning. They are changing colour right before our eyes. And their eyes are improving. No discharge at all. Some irritation in E17’s right eye and in both eyes of E18. My goodness from those poor crusted babes that looked like their eyes came out of a horror movie, they are looking like really beautiful strong eagles today,

They might miss that lady with that veil that has been feeding them all that yummy food. Wonder if Harriet and M15 supply quail?

4 February.

I am going to mention Laura Culley twice. Oh, I admire this woman and her wisdom about birds and, in particular, hawks and falcons. Indeed, I know much more about those smaller raptors than I do these big Bald Eagles. I know that a lot of us worry when we see the little ones bopping one another. It is funny for about a day or two and then we get afraid for the smaller one. This is what Laura tells me about worrying and I want to share it with you. “Worrying is creating an outcome in our minds that hasn’t happened yet. Soar above it all and look at the big picture.” That has helped me in other times, too, if I can remember it. Maybe it can help you, too, or someone you know.

Culley also explained to me the difference in the two terms, formel and tercel. When we talk about raptors, the formel refers to the female. The tercel is the male. ‘Tercel’ comes from the word third because it is believed that the third egg was always the male. In this instance, it is the second egg. In the case of our Bald Eagles as well as the hawks and raptors that I love, the female is the largest. This is called Reverse sex-size diamorphism. It seems that we are already seeing this in E17 and E18, perhaps.

And this whole thing about dominance and territory leads perfectly into this unusual story.

Starr with Valor I and II, February 2021. Image @2021 Stewards UMRR

How many adult Bald Eagles do you see sitting on branches of the same tree? If you said three, you are right. These three eagles have a nest in a tree on the Mississippi River near Fulton, Illinois. Just from reading about E17 and E18 we know that even eaglets fight for dominance and for food. And that is what makes this nest so special. There are two males and a female and, apparently, they are an Internet sensation.

It all began in 2012, nine years ago. Valor 1 (one of the males) was mated with a female named Hope. They had a nest along the Mississippi River. But Valor I was anything but a good dad and mate. He was completely irresponsible in taking care of the eaglets when it was his turn. Hope incubated the eggs almost entirely by herself. Valor 1 did not bring food to her nor did he appear to relieve her of her duties. He was a dead beat eagle dad. There is no other way to say it. Hope had to stay on the nest almost the entire time. But she had to get food and take breaks. Sometimes Valor 1 would incubate them but only for about ten minutes before he got bored and left. This is starting to sound like what happened to Daisy the Duck, right? The winter along the Mississippi was very cold and none of the rangers believed that the eggs would hatch. To the surprise of everyone, they did! Hope had to leave the little eaglets to get food for the three of them. Valor 1 did not help at all. Just like Daisy, Hope had to get off the nest to go to the bathroom and to get food for both her and her babies. Sadly, when they were four days old, while Hope was away both eaglets fell off the nest and died.

Next breeding season, in 2013, Hope wasn’t having anything to do with Valor I. A new male appeared despite Valor 1 hanging about the nest continually. Hope and her new mate fledged two eaglets in 2013 and 2014. Yeah for this great mom! Interestingly, in 2015, Hope mates with both males and that year, another two eaglets fledged. The following year, in 2016, Hope again mates with the two males who are now named Valor I and Valor II. All that is known is that three eggs hatched. The monitoring camera broke down and the rangers cannot say for sure what happened on the nest after hatch. But something magical happened that year. Valor I was seen helping with more of the nest building. He incubated the eggs and he helped provide food. In other words, he grew up! Maybe it was by watching what Valor II was doing?

The images below show the three Bald Eagles sharing nest renovation duties in November, 2017.

In 2017, the three assumed all duties equally. They replenished nest material, incubated the eggs, brought in food for one another, protected the nest, and fed and took care of the two eaglets that were born. On March 24, the nest was attacked by two intruders, both Bald Eagles. Hope fought them off as best she could but she was fatally injured. Her body was never found, Valor I and II protected the eaglets and remained unharmed. And, to the shock of all, Valor I and II took on shared ‘eaglehood’. They took turns keeping the eaglets warm and safe, they brought food and feed the little ones, and they guarded the nest. Indeed, they did all that and fought off continued attacks by the two intruders throughout April and into May. Both of the eaglets fledged on May 30. Isn’t that amazing? Oh, I wish Daisy had help like this.

In the image below, one of the Valors (on the right) is defending the nest from one of the intruders on 4 April. You can see the grey eaglets on the nest just behind the parent. Attacks like these continue for the entire month. Most believe that the two intruders wanted to take over the nest. Bit Valor I and II did not let that happen nor did they allow any harm to come to the little ones. What a team.

One of the two fathers fighting an intruder while brooding the eaglets. Image @2021 Stewards UMRR

That fall a young female appeared. In September, Rangers noticed that she was collecting material for the nest. She mated with both Valor I and II and the trio shared all responsibilities for the nest and the eaglets. Two eaglets hatched in 2018. One is known to have died when it was about a month old. The other one fledged early but was seen by the rangers in the area and it was doing just fine. The rangers named the female Starr.

The two images below show Star and both Valors working on the nest in November, 2017.

The three work on the nest together. Image @2021 Stewards UMRR
Valor I and II with Starr in the old nest. Image @2021 Stewards UMRR

In 2019, the three raised three healthy eaglets that fledged.

In 2020, two eggs were laid on 14 and 17 February. They hatched on 23 and 24 March fledging on 10 and 16 of June. Everything was wonderful until Derecho entirely destroyed the beautiful old nest in August. A derecho is a long straight line windstorm that can have speeds up to that of a hurricane. Everything was torn apart. But that did not phase the three Bald Eagles. They started to rebuild their nest across the Mississippi River from the ole one. The trio can only be seen from a distance until a new streaming camera can be installed.

In the image below, Starr is on one of the branches along with one of the Valors. It is 3 February 2020. This will be their third breeding season together. The other Valor is bringing in sticks to help continue to build the new nest. Note how shallow the nest is now. Each year they will add more and more twigs and branches and soon it will be as large as the old nest.

Valor I and II and Starr work on new nest in February 2021. Image @2021 Stewards UMRR

This week Starr has been observed mating with both of the Valors. The three appear to have a fantastic relationship that is nothing short of miraculous in terms of Bald Eagle behaviour.

Every duty that is associated with a Bald Eagle nest from nestorations, to catching food, incubating eggs, feeding nestlings, and teaching eaglets is now shared equally. The rangers have not observed any animosity. This is such a rare occurrence that many are baffled at why it has worked so well. What they do know is that having three to share the duties has ensured up to this season anyway, that every breeding season has fledged healthy juvenile Bald Eagles. It certainly underscores that old saying, ‘If we just work together, we can do anything’.

I will bring you updates on this nest as more news is available. For now, the threesome continues to mate and bring sticks to the new nest. E17 and E18 are gaining weight, eating well, and their eyes are improving. I was sure hoping they would be home Friday (the 5th) but now think it will be Saturday. Oh, gosh. Harriet and M15 will hear their little peeps and be so excited.

Take care everyone. Thank you so much for joining me today. Please stay safe and well.

Why are female Red-tail Hawks almost always 30% larger than the males?

It is called Reverse Sex-size diamorphism. There are several theories as to why this happens with Red-Tail Hawks.

The first is that the females had to be larger to protect themselves from the feisty males.

The second is that the females selected smaller males to be their mates because the size difference allows each of them to hunt different prey and reduce any competition for food between the pair. Raptors that hunt birds are generally smaller and faster with the female specializing on larger prey. At the beginning of the nesting season, the female becomes an active hunter and again when the nestlings are larger. Generally the adults tend to partition the prey resources in their territory.

Another theory is that the females need to be larger because they must accumulate reserves in order to produce eggs. When they are incubating eggs and brooding young, they rely on the male to feed the family. Red-tail hawks are usually born in April when the prey are sluggish and just coming out of hibernation. Small males can make quick turns. In the case of the Red-tails on the Cornell Campus, Arthur W, the male, is known as the ‘stealth bullet.’ He is quick, fast, focused, and quiet when he hunts. Big Red’s former mate, Ezra, was like Arthur W a great hunter but he was also about 30% smaller than Big Red as is Arthur.

Ezra has his wings spread and his legs tucked tight. If you look closely you will see that he is delivering two items to Big Red. The first is a snake and the second is a flower!
It is very difficult to get Big Red and Arthur to stand up straight at the same time. They certainly do not listen to requests from humans!This is the closest I have come to finding an image that might be able to show you the difference in their size. Big Red is on the left and has her head leaning back preening and she is a little more slumped than Arthur who is on the right.

In terms of the nestlings, the only way to positively known the gender of the bird is through either a DNA sample or you see them laying an egg when they are older. Everyone likes to guess the sex of the chicks growing in the nest cup. Using reverse sex-size diamorphism, we speculation whois a female by their overall size as they grow in the nest and the size of their feet. But again, no one can be absolutely sure. In the past one of the small nestlings was always believed to be a male. This particular bird injured its wing and, as a result, had to be taken to a vet. The bird’s DNA was tested and, to the surprise of many, it was determined to be a female. So not every small Red-tail Hawk is a male!

In terms of the relative size of each J, J1 is the largest of the three. Early in its development, everyone noticed the large size of its feet. Now as a juvenile, J1 remains the largest of the three siblings. But there is something else about J1 that I personally find fascinating. J1 is very much interested in nest maintenance. She can be seen, even today, mimicking Big Red in attempts to vent the nest bowl. She rearranges the nest twigs and on the second day after she fledged, she brought a branch to the top of the Rice patio. There seems to be 100% agreement that J1 is going to be a good mama like her mother, Big Red.

J3 in the front and J1 behind watching J2 fledge. Look at the difference in the size of their legs as a starting point.

J2 on the other hand is also a large bird, not as large as J1 but larger than J3. J2 was actually the first egg to be laid but the second to hatch and is, therefore, actually the oldest. His fledge was more like a fludge when he climbed up on the light box and then slipped but his flight was still remarkable. J2 has continued to be a very, very strong flyer already interested in hunting. The shape of “his” head – you will notice that I continue to use the term “his” – is also different than that of J1. He has an intense focus and besides bugs and insects he has already been interested in small birds in the territory. To my knowledge he has not caught one. He is also very aggressive. A few of us believe he is truly a male and will be a great hunter like his dad, Arthur W.

J3 eating his first prey drop after fledging.

J3 is the problem child that everyone loves. . J3 was born four days after the other two and it was also the last egg to be laid. Taken together, J3 is actually a week younger than its siblings. That is a lot in the life of a Red-Tail Hawk chick. It may also account for the fact that Arthur W brings food to the nest tower in an apparent effort to feed J3 away from the two larger siblings. Let me try to explain what has been happening. Normally the juveniles are spread out being individuals. This trio is quite different according to the people who have monitored all of the broods on camera (since 2012). It is because they tend to congregate together. To hang out. If one is on the Rice patio, all three might be there.

All three on what is called the Rice patio. Arthur W often makes food drops here but it is also a safe and flat site where they can sleep in the sun or practice their skills.

They might all be on one of the towers including the nest tower. Still, on occasion, they go their separate ways.

J1 in one of the oak trees near the Fernow Building looking at a squirrel.

A prey drop is just that – one of the parents dropping lunch. The juveniles will, unless they have recently eaten, fight for the food with the most aggressive mantling the prey. Unless the prey item is too large for the chick to eat all at once, sharing doesn’t seem to happen. So, because of J3s size and a seemingly lack of aggressiveness in comparison to J2, J3 is somewhat at a disadvantage. This is the reason that I believe Arthur W still supplies food on the nest to the little guy.

Arthur has been dropping lunch off to J3 for several days now. This was around 3pm. He seems to be looking for J3 who arrives almost immediately.
J3 mantling the prey that Arthur W dropped on the nest. Remember mantling is a way of protecting the food item so that no one else can steal it.
J3 finishing up his afternoon snack.

For now, the gender of the three juveniles is sheer speculation. There are no banding practices and no GPS monitors on the Js. In other words, no identification. It is only when one of the juveniles might find its way to the vet and be both recognized and tested that the sex would be determined.

Tomorrow we are going to talk about the importance of preening.