Is there ANY truth whatsoever behind the eaglet one? I remember hearing something about how the 1st borne chick will often outgrow the others and potentially directly or indirectly kill the runts or last born. Though again, I’m unsure if this is true whatsoever, or even if it happens with others birds.
Well, I only know about Bald Eagles, and I’m not an expert. But if you watch a Bald Eagle nest cam (there are many popular ones these days), it’s very obvious that the youngest chicks are smaller (they hatch days apart, not just hours), and it can get pretty rough at feeding times. The biggest chicks demand food and they can be aggressive getting it, but generally, the smaller ones just wait their turn. I wouldn’t be shocked if there were some injuries, but they aren’t murdering their siblings, that would be big news if it were caught on camera! Instead, it’s quite common for all of the eaglets to survive.
If you think about it, it’s unlikely that these nest cams would be so popular if the chicks were regularly killing each other (or getting each other killed). Deaths do occur, and it’s sad, but fledging success rates are very high. So it’s not a guaranteed happy ending, but it’s rarely a total tragedy.
When the youngest eaglets do die, it’s often due to exposure or disease, which simply affect them more because they are smaller and weaker, it’s not the fault of the older ones. Even if they just didn’t get enough food, that would be a case of the parents not feeding enough or of there not being enough food to be found, which are also not things that the older eaglets are responsible for.
So no, on balance, I don’t think that older eaglets are directly or indirectly responsible for the deaths of their younger siblings. I’m not saying it can’t ever happen, but they’re certainly not deliberately trying to kill each other, so even if it does happen, I don’t see how it can be their fault!