Apr 03 2014

Three Eaglets … For Now

Published by at 7:47 am under Birds of Prey,Nesting & Courtship

Third bald eagle egg hatches at the Hays nest (snapshot from the Pittsburgh Hays eaglecam)

Yesterday afternoon around 5:00pm the third and final egg hatched at the Pittsburgh Hays bald eagle nest.  This happened during rush hour so a lot of us missed it … or did you stay late at work to watch?

Click on the photo above to watch the eaglet emerge from his egg.

An hour later all the eaglets are visible as Mom feeds the oldest chick.

Her actions reminded me that we will soon see a characteristic of bald eagle family life that’s quite different from peregrines’ –  the tendency for the oldest eaglets to thrive and the youngest to die, sometimes killed by their siblings.

Bald eagle eggs hatch asynchronously so each new eaglet is two days smaller than the previous chick.  Bald eagle parents feed the chick that asks for food, and since the oldest is bigger and more active he’s fed more than his siblings.  Eagle chicks are aggressive toward their siblings and the parents don’t breakup the fights.  The third chick often starves.  Cornell’s Birds of North America Online describes it this way, referring to a study in Saskatchewan:

Hatching asynchrony and differential growth leads to differential mass in siblings, facilitating competition and fratricide. Sibling competition and mortality is greatest early in nestling period, when size differences are greatest. Third-hatched chicks in Saskatchewan nests received little food and usually starved.

This behavior is quite different from the peregrines’ lifestyle.  Peregrine falcon eggs hatch almost simultaneously so all the chicks are close in age and size.  The last chick may be smaller at first because he hatches two days later, but peregrine chicks are not aggressive and their parents make sure everyone eats at every feeding.   Mother peregrines “chup” to their babies to encourage them to stand up and be fed.  Click here see how effective (and cute) this is.

For now there are three eaglets at the Pittsburgh Hays eaglecam … but be prepared for the day when there might be only two.

 

(videos and snapshots from the Pittsburgh Hays eaglecam)

30 responses so far

30 Responses to “Three Eaglets … For Now”

  1. Kayon 03 Apr 2014 at 10:05 am

    Hope all survive. The year I watched the eagles in Iowa, I believe all the eaglets did survive even though there were fights among the siblings from time to time.

    A comment on Dorothy at COL – this morning it appears she is sheltering the egg and does look a little confused and frazzled. Is E2 nearby? I haven’t heard him. Will the Game Commission “catch” Dorothy to do a health check on her as they usually do on banding day or will they just leave well enough alone? Sorry to see her breeding days end.

  2. Kate St. Johnon 03 Apr 2014 at 10:29 am

    Kay, E2 is around. He brings food to Dorothy on a regular basis. As I write this she is on the nest perch with a full crop — just ate.
    The Game Commission is not going to capture Dorothy for a health check. She is an “elderly” peregrine so the fact that she has health issues is quite predictable & not curable. Nature will take it’s course.

  3. Kate Zingarellion 03 Apr 2014 at 10:40 am

    Kate,
    If the third eaglet is struggling, would it be too invasive to take the eaglet and raise it for the zoo or aviary? Just a thought, probably a completely wrong idea and that action would not follow natural eaglet life/death.
    Thank you for your blog. I’m learning so much as I watch this incredible nest cam.

  4. Sue Vertosickon 03 Apr 2014 at 10:42 am

    Is it true that the sibling competition is much more of an issue if there is a limited food supply?

  5. Kate St. Johnon 03 Apr 2014 at 10:53 am

    KateZ, No the third eaglet will not be “rescued.” This is the bald eagles’ lifestyle. We are privileged to watch but we must not interfere. Nature will take its course.

  6. Kate St. Johnon 03 Apr 2014 at 10:54 am

    Sue, yes sibling competition is much more pronounced when there is a limited food supply. This lifestyle ensures that at least one very strong chick lives to adulthood rather than lose the entire clutch.

  7. John Englishon 03 Apr 2014 at 1:12 pm

    We need to be careful and not anthropomorphize wild creatures. Rearing a captive eagle could possibly mean an eagle that could never be released to be free in the wild. However much we’d like to bond with “our” birds we have to be careful not to regard them as we would personal pets. These birds have gotten along for thousands of years without interference on our part. Unless humans harm the birds in some fashion we need to back off and let nature and instinct take its course.

  8. Kate Zingarellion 03 Apr 2014 at 3:27 pm

    Thanks for the answers and comments. I knew the answer would be no, but thought to pose the question. I agree that nature is nature and we are privileged to be able to watch.

  9. Janet Campagnaon 03 Apr 2014 at 3:41 pm

    I’m no expert, but I think this whole “catch and rear in captivity, with hopes of releasing into the wild” thing is only done when in sheer desperation, as when a species is at or near extinction, as was done with the California Condor. As John English said above, this is a bird which was greatly harmed by humans, so humans stepped in to help. It’s actually good news if a species doesn’t need our help.

  10. robinon 03 Apr 2014 at 3:54 pm

    Hi kate thought fratricide is rare in bald eagles , hornby study suggests that

  11. Kate St. Johnon 03 Apr 2014 at 3:55 pm

    Janet, very well said! Yes, it is such a joy that the peregrine and bald eagle populations are doing so well that we don’t have to intervene to prevent extinction. Those days were a bad, sad time.

  12. Kate St. Johnon 03 Apr 2014 at 4:10 pm

    robin, among bald eagles survival of the last-to-hatch chick depends primarily on whether he gets enough food. If he doesn’t he weakens and cannot hold his own among aggressive siblings. Cornell’s Birds of North America explained that in the Saskatchewan study the third chicks usually starved.
    Fratricide is not common among bald eagles but it happens enough that it is mentioned in the species account.
    It is so rare among peregrines that it’s not mentioned at all.
    It is so common among golden eagles (Aquila chrysaetos) that it’s a defining characteristic of their family life. One one chick per nest among goldens! Read more here: http://en.wikipedia.org/wiki/Golden_Eagle#Cainism [Golden eagles are not directly related to bald eagles -- different genus.]

  13. Sueon 04 Apr 2014 at 9:49 am

    I just saw Momma feeding the third baby :)

  14. Kate St. Johnon 04 Apr 2014 at 9:57 am

    Sue, that’s great news. Thanks for sharing.

  15. Sue Vertosickon 04 Apr 2014 at 2:43 pm

    Tougher viewing this afternoon. The oldest chick definitely received the bulk of the feeding while numbers two and three struggled for Mom’s attention. When she did turn to one of them, the oldest chick aggressively pecked them down. It must be harder to hunt in the rain, but the youngest two got next to nothing in this most recent feeding.

  16. Brendaon 06 Apr 2014 at 9:03 am

    I think there are only two now. Would they eat the third one if it died?

  17. Kate St. Johnon 06 Apr 2014 at 9:59 am

    Brenda, don’t know if they’d eat it.
    Golden eaglets sometimes eat a sibling but they are very different eagles from bald eagles. Goldens are meat eaters, not fish eaters. (See earlier comment about golden eagles.)

  18. Brendaon 06 Apr 2014 at 2:43 pm

    Woo hoo!! There’s still three!! Getting their grub on now!

  19. Bill Ghriston 08 Apr 2014 at 12:29 pm

    Just watched a feeding (April 8, noon). All three chicks got to eat. The little one was last and least, but seemed to be satisfied with what it got. At first #3 was blocked out by its siblings, but when #1 stopped eating #3 made it up to the front. That would seem to suggest that abundance of food does make a difference in how aggressive the older chicks are to the younger. It will be interesting to see what happens as they get bigger and it takes more food to satisfy them.

  20. Kate St. Johnon 08 Apr 2014 at 12:48 pm

    Bill, thanks for the update on the eaglets. The good news is that as they get bigger the competition eases considerably. The longer #3 does well the better it gets for him.

  21. Sueon 08 Apr 2014 at 2:56 pm

    I just watched a feeding as well. Mom didn’t feed #3, and #1 was very aggressive toward #3, striking and hitting him/her twice. I sure hope it doesn’t continue. #3 does seem to be very strong for such a little one, however. I’m happy to read that #3 got fed earlier. I’m emotionally attached now :)

  22. Kate Zingarellion 08 Apr 2014 at 3:50 pm

    Sue, I was watching too and felt that #3 was clearly being left out of the feeding, but, another fish just appeared in the nest and all 3 seem to be on equal footing again. I agree that the abundance of food is making a difference here for #3 surviving these first crucial weeks.
    What a fantastic learning opportunity this is.

  23. Carole Robinsonon 08 Apr 2014 at 4:29 pm

    Has anyone seen the third eaglet get fed since noon today, Tuesday, April 8th?

  24. Sueon 09 Apr 2014 at 7:09 am

    Kate, thank you for the update. I’m so hopeful for #3.

  25. Brendaon 09 Apr 2014 at 7:55 pm

    I’m rooting for #3 too!!!

  26. Sueon 10 Apr 2014 at 11:01 am

    Just watched Dad give #3 a big meal.

  27. Kate St. Johnon 10 Apr 2014 at 11:10 am

    That’s great news, Sue. Sounds like #3 is doing really well. The first week is the toughest & he’s held his own. Good eaglet!

  28. Sueon 10 Apr 2014 at 2:02 pm

    He was actually defending himself today against #1. He’s still pretty small compared to the other two. It would be so exciting if this pair was able to raise three healthy eaglets!

  29. Brendaon 11 Apr 2014 at 6:55 pm

    The little one doesn’t look so good today, I’m bummed out.

  30. Brendaon 11 Apr 2014 at 7:06 pm

    Ok, now they are all getting something to eat, whew.

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