Tuesday, May 03, 2016

Decorah North: DN1, DN3, and today on the nest

Watchers of the Decorah North Nest got quite a shock today after DN1 went after DN3 with a ferocity we haven't seen at any of the bald eagle nests we watch. It looked liked this:
  • Mom North lands on the nest, chasing away a sparrow that was stealing straw from the nest. DN1 and DN2 are huddled together at about 7:00 on the left side of the nest, while DN3 is laying at about 4:00 on the right side of the nest.
  • Both eaglets rise to a sitting position.
  • DN1 dominates DN2, pecking and pulling on DN2's left wing. DN2 submits and DN1 stops.
  • DN1 shoots poop, staying at roughly 7:00..
  • DN3 sits up and walks over to the turkey wing at about 3:00, where it appears to be look up at Mom. Keep in mind that the eaglets are walking on their tarsi, not their feet.
  • DN1 walks from 7:00 to 3:00 and begins a dominance interaction with DN3. In addition to pecking, DN1 bites and pulls on DN3, who submits. 
  • As DN3 submits, it rolls against DN1, scraping DN1 with its talons in what appears to be an accident.
  • DN1 resumes the dominance interaction, pulling and biting at DN3's wing and body and flipping DN3 over. DN3 remains in a submissive posture.
  • DN1 pulls DN3 up by the 'scruff' of its neck four times
  • Mom North, who has been watching the entire interaction, walks over and looks at DN1.
  • DN1 ceases the interaction, although we don't know to what degree Mom North interfered with it. Was DN1 ready to quit given the lack of a response from DN3, or did Mom's arrival distract DN1?


Following this event and subsequent battles, the ugly specter of siblicide - one sibling killing another - leapt to everyone's mind. So how common is siblicide in bald eagles? Sources disagree, with some referring to it as relatively common (University of Nebraska, American Eagle Foundation) and others calling it fairly rare (Hornsby). It hasn't yet occurred at any of our cams - not in Decorah (since 2008), not at Decorah North (since 2016), not in Fort St. Vrain (since 2003), and not during the one year we were able to watch Eagle Valley (2013). Our nests have different parenting 'styles', levels of food availability, surrounding environments, and nest invaders, but to date all eaglet fatalities have been caused by hypothermia, predators, and suspected disease. Why did DN1 take after DN3 and (to a lesser degree) DN2 today? We don't know, but as tough as it was to watch, it wasn't especially prolonged and didn't lead to death.

People also worried about a lack of food deliveries to the nest. While we don't know why parents don't pile up the pantree here as they do in Decorah, birds of prey (even young ones) can go a long time between meals. The eaglets remain healthy, alert, and pooping, which tells us that their digestive systems are working just fine. They are moving around the nest, interacting with one another and with parents, and showing interest in their surroundings. I'm sure they would like a meal, but they aren't starving yet and won't be for some time.

Several people referred to Dad and Mom as 'bad' parents. Again, different nests have different parenting styles, but eagles don't divide neatly into human narratives of good and bad behavior. It is a warm day, the young don't need brooding, and either Mom or Dad have been perched nearby much of the day. They are taking care of their young as they see fit, and we know from studies on human-raised birds that young birds have very different needs than young humans.

We've also been asked if we will rescue DN3. Absolutely not. We might consider interfering if the situation were human-caused, but what happened today was completely normal from an eagle perspective. If we rescued every eaglet we were concerned about, there would be no wild eaglets left to watch. It is very important to keep today in perspective. This is one of the first days we have seen a lot of concern about Decorah North. For the most part, the parents have acted according to our expectations: feeding, interacting, brooding, and in general caring for their family. It is also the first day - the first time - we have seen that level of aggressive interaction in one of the bald eagle nests we watch. But none of it was out of line or outside the parameters of normal eagle behavior. If eaglets died after a warm day with just one meal, we wouldn't have eagles to admire and worry about.

In 2011, a follower sent me a lovely watercolor painting of the fledglings at the Decorah nest. It said "You are braver than you believe, stronger than you seem, and smarter than you know." It remains a favorite artwork of mine and I often think of it when I am concerned about the eagles. As anthropomorphic as the painting may be, eagles are truly stronger than we think and often smarter than we know. As much as we love them, they are only their own and what we saw today was simply part of the way they live their lives.

Note: Hornsby follower gzebear compiled observations from 147 nests checked in an 8 year period and found only a 2% incidence of siblicde in hatches of 2, and 3.8% in hatches with 3. Follow the link to read gze's data, references, and additional comments from contributors to the thread. I think it might be time to revisit the whole subject of three-egg versus two-egg clutches. How common is one versus another? Are there regional differences? Is it an inheritable trait? Do we have more three egg clutches than we used to? It's off-topic here, but I subject that interests me quite a bit.

31 comments:

Deb Johnson said...

Very well stated.

Joan said...

Thank you for the excellent explanation/overview.

Dianne Marks said...

I am sure this was not easy for you to comment on, yet felt it was necessary for all of us to hear some comforting soul to calm our fears and frustrations. Thank you for your words of wisdom. Deep breathes!!

Danielle said...

I always fear for the little ones, but must remember that life is even harsher when they leave the nest. I think the video below shows what the eagle's life will be once away from the nest. As hard as it is to watch I know that these lessons in the nest will prepare them for the tough outside world.

Conowingo Dam Bald Eagles - https://vimeo.com/152926627

Gnarlodious said...

looks like common bird behavior. Kookaburras are known to toss the smallest chick overboard, leaving more food for the most aggressive. If found and adopted they make a fine pet, while the largest birds are not pet material.

Can't Touch This said...

Well stated. It's hard to watch but we have to trust the eagles know what they're doing and we don't know all there is to know about them. It is a privilege to be able to observe them so closely.

Can't Touch This said...

Well stated. It's hard to watch but we have to trust the eagles know what they're doing and we don't know all there is to know about them. It is a privilege to be able to observe them so closely.

Vicki~D said...

Thank you for posting the Video.

Loretta King said...

We are the observers of Mother Nature in the raw, thanks to installed cameras. What we see is how wild animals have always behaved and we should not interpret their actions with our human emotion and logic nor demand or expect any human interference in their day to day life. the only time I have seen any human interference in an eagle nest is when an 4 week old eaglet was tangled in fishing line and even then, permission had to be obtained and was only granted because fishing line is man made not a natural product. I watch several nests and it is a privilege to be able to see how animals manage to survive in radically different climates and terrains. Would that all peoples could observe this and then never consider the destruction of the wild but work to preserve it.

molly_dc said...

hi raptor rescue. thank you so much for the honest and thorough update. i especially appreciated how you contextualized the process unfolding in dnn. understanding how this compares to other nests rounds out my comprehension of what Im seeing. i also appreciate that you did not harp on the fact that theses are eagles in nature and not human. i think we are all very well aware that we are watching eagles and
nature. chat room respondents seem quite intelligent. thank you for treating us as such.

William Bonney said...

If we rescued every eaglet we were concerned about, there would be no wild eaglets left to watch.
Well explained but I am not asking for EVERY EAGLE to be rescued. Just one! If this baby is crippled, there is no justice. He will not live. The aggression posed by #1 looks over the hill to me and many others. I feel like I am watching a SNUFF film and waiting for the baby's demise.
If there is no one interested in taking responsibility for the rescue of #3, I would gladly volunteer to help or you tell me what to do. What you are saying makes sense, but the brutality exhibited by #3 is off the charts. I rather go for a rescue. But then what?
More information would be appreciated. Have any ever been rescued?
My email is vbfever1@hotmail.com I live in S. Cal.

Patricia F. said...

Thank you for all of this information it truly helps to keep things in perspective as to the behavior of our beautiful eagles and eaglets.

Arcadia said...

William, there was an eaglet I think two years ago in another nest whose wing had been caught in mud in the nest, and it could not get out. A worker rescued it. The eaglet got cleaned up and then put back in the nest, and the parents came and fed it again.

William Bonney said...

Arcadia, thanks for the update. Really, really appreciate it. I think the mother instinct is strong in most animals. I surmised it could be done but was not positive.
We help MANY animals but some humans rely on the excuse it is nature's way & refuse to do anything..
I saw a mountain lion caught in a foot trap. Those two park rangers went in and freed him.
That is a human being's way...

Patricia said...

Could you provide the source of your comment attributed to American Eagle Foundation. ( siblicide in bald eagles? Sources disagree, with some referring to it as relatively common (University of Nebraska, American Eagle Foundation)) That question has been asked a few times on their own web site and they repeatedly say they don't believe it's common at all and that they have never seen it since they have started watching the nests. Just wondering where this quote is coming from.

Thanks!

ferniefootloose said...

Thank you, well stated & informative.

Judy Shepps Battle said...

Thanks Amy, your explanations are both compassionate and reality based. Let me just add that early this season at the SW Fla nest, the level of attack by the older sibling (only two eaglets) during the early days of life was actually more severe than what we saw yesterday. The older sib would drag the (three day younger) sib around the nest by the wing and we all started to read up on siblings killing one another and to prepare for what seemed inevitable. The younger would go into submissive posture and eventually pop up to begin the process again. SW Fla is also an area where the hunting is ok, but surely not as plentiful as we have seen on the Decorah nest located above the fish hatchery. To bring this story up to date, the youngest fledged yesterday at 96 or 97 days and is flying around like an old pro. So, keep the faith folks. Momma Nature is running the show but dem eagles are pretty darn smart .

Pat L said...

That little sparrow/wren was around the other day when I was watching and all 3 of the eaglets perked up and got protective of the nest. It was quite cute to see. I have been concerned about #3 getting enough to eat. It's so much smaller than #1 & #2. But it is nature and survival of the fittest. It just seems a shame that if humans see that an eaglet isn't going to make it if it stays in the nest that it couldn't be hand raised and then returned to the wild.

It would be nice if DNN had a chat room.

Felix Nuts Tomcat said...

DN3 is quite a bit smaller than its siblings making its situation worrisome. But in the Decorah area food is plentiful. It still has a fair chance at survival. I wouldn't start playing in my mind gloomy scenarios just yet.

jw said...

Sibling rivalry at it's best. #1 is the leader of the pack and isn't going to let them forget it. Not just yet. From watching other nests, this doesn't last long.

Kelly McCreight said...

I am very upset watching the video of 5-3-16 and seeing 1 attacking 3 ... I don't get to watch enough. Is 3 getting any food at all? It's so small.

Kelly McCreight said...

And why is 3 so small?

Dale Wilson said...

From what I saw on the stream earlier this evening, I will be very surprised if DN3 survives.

There are so many bare patches all over its body; the one wing looks badly deformed now; and even its feet look underdeveloped/deformed as well.

And for a little bit, the parent was also completely ignoring DN3. He/she did eventually go over to DN3 and tried crawling on top to protect/warm him/her. But DN3 kept moving away, almost seeming to imply that "you did not protect me before from DN1, why bother with me now?".

I am feeling very sad right now because I do not think DN3's outlook is very bright.

Terry Magestro said...

If DN3 gets tossed out of the nest, will someone rescue it?

anonymous said...

I am not sure DN3 would survive if DN1 continues attacking DN3. Mom or dad seems doesn't bother to intervene. Hope DN3 will survive and grow.

Pat L said...

I've been away all weekend without access to USTREAM. I was a little hesitant to log-in this morning, afraid to find DN3 gone. I am happily surprised to see what appears to be DN3 still in the nest. I haven't gotten a good look, it's been wedged between DN1 & DN2 under mom/dad.
I hope this little fella gets a chance to soar.

anonymous said...

I see DN1 repeatedly attacked DN3 for no reason. I have bad feeling about DN3 could be dead anytime. Seems DN1 wants to destroy DN3. I have decided someone needed to rescue DN3 from DN1. Or remove DN1 out of nest so DN3 could live peacefully with parents.

dennyk58 said...

Blogger dennyk58 said...
Thank you to the monitors for zooming out quickly when Lil peep was being picked on. This nest is becoming very hard to watch as an adult, let alone for children. With that being said, I know there is no intervention unless it is brought on by humans. I am certainly not an expert, but I have observed the parents bringing placenta to the eaglets many times. While we do not know what animal the placenta came from, one can assume it is from the farm below. So the question that I must ask is: if the placenta contained environmental contaminants as antibiotics, steroids, etc., that can certainly have played a part for eaglet 1 to be super aggressive (more than has been observed at other nests) and why eaglet 3 is malnourished and why the parents are not feeding. This is important as this nest could, very well, have been affected by humans, certainly not meaning to do the same. We do know that in some cases raptures are dying across the United States for no apparent reason. Of course, weather conditions, etc., may have been the cause. However, human intervention should happen to determine exactly what is happening at this nest. Thank you.

Patricia said...

Denny I was wondering the same thing when I heard and saw them eating placenta at least twice in the nest. That placenta would have high concentrations of hormone's in addition to drugs added by humans.

Julz Baker said...

I understand that you can't rescue them all, but since the eaglet is abnormally small, wouldn't you want to go rescue him to be able to figure out why he/she is so small? It would be a better solution rather than have it starve to death or have its sibling kill it.

Julz Baker said...

I totally agree with you William. We are not asking them to rescue them all, but this little one needs to be brought to safety. Also, they need to study it to figure out why it is so small. I know it is nature, but when you put up cameras and invite caring, loving people in to watch, of course we want what is best, and what is best is to rescue this baby!!!