I have been excited to witness rare behavior of the Eastern Bluebird. I have a juvenile that is helping his parents feed his younger siblings. I first saw this bluebird, thought to be a male, on July 21, take a mealworm from a close by feeding dish, fly to and cling to the outside of the nesting box, looking around for about thirty seconds, then put his head into the entrance hole, and pop it back out, without the mealworm. I have been watching for this behavior, for years, as I had read, that it occasionally, occurs. This just happened to occur at the nesting box, very close to my house, and I had binoculars in hand, so I saw the behavior, very clearly. Of course, I was then hoping to see him do it again, and be lucky enough to get a picture for documentaion. The next evening, after work, I had my camera ready, when I put some mealworms out, but did not see the juvenile make an attempt. The following day, I was off work, and was setting my camera up, before putting any mealworms out, when the juvenile landed on top of the nesting box. He already had a little spider in it's beak and proceeded to feed a sibling without hesitation. I was really excited, because he had to intentionally hunt for that spider and share it, it was not a convenient mealworm. This bluebird, fledged from this same nesting box, just six weeks prior, and while hunting on his own, still will occasionally beg his parents to feed him. I believe he is the only one of the five that survived after their first week post fledging. That story and pictures are currently featured on the Cornell Nest Watch, web site. Since that first week, after fledging, I have seen him with his parents, almost daily, but never saw the others. After his Mom started incubating her second clutch, the juvenile would often just perch on top of the nesting box, while Mom was inside, with Dad sometimes joining him.
I continued to watch the juvenile feeding his siblings, at the nesting box, until they fledged, five days later, and since then, to the present, almost another week, he continues to help them feed them, up in a large oak tree in my yard.
I sent the information to Cornell Nest Watch, and immediately got a reply from the project assistant. As it turns out, this behavior is more rare, than I had thought. I will copy and paste that email response, I received from Cornell. At 5, in 5,000, that's one special little Bluebird, I have. :)
I also had three bluebird pair nesting in my 2 acre yard, for the first time, this season, a territory size, generally required for one pair. Twenty-Seven was my final fledge count! Plus Six chickadees, and my first time, nest box, residents, four Great-crested Flycatchers, fledged. :) It has been one heck of a busy, nesting season, with all kinds of firsts! I don't know about the birds, but I'm kind of tired. lol
I'll also include links to view the pictures and short video clip, of the juvenile's behavior.
That is quite an amazing behavior to watch, especially in Eastern Bluebirds. I'm very glad that you were able to capture a short video of the event as well.
Typically, this species is not known for the juveniles assisting in the breeding process. However, they do have cousins that are very active in this assistance. Western Bluebirds often have helpers at the nest. These helpers are either adult males or the fledglings of previous nest attempts.
There have been many studies as to the results of helping. Typically, the pair that is helped can feed the chicks less often, have an increased fledge rate, and often tend to live longer. As for the helpers themselves, the do not seem to be as well off as the non-helpers. It is thought that this trend is either caused by lack of partners in the area or through the potential of inheriting the nest site in the future.
Though Eastern Bluebird helpers rarely happen, they do occasionally occur. Typically the rate is about 5 in 5,000 nests, with most of these helpers being fledgling from nests earlier in the season. So, this is something quite rare that you have.
As for the other fledglings, they might have been just as successful as the one that you continue to see. However, they have probably gone their own way by now.
Enjoy the end of this nest attempt!
NestWatch Project Assistant