Eastern Bluebirds--Juveniles Helping Parents Feed Nestlings

Several days ago, I noticed the bluebird juveniles, now eleven weeks old, visiting the nest box, looking in on the nestlings.

After seeing one of the juveniles fly inside the nest guard and rest there repeatedly, I wondered if she was displaying curiosity or expressing a desire to participate in caring for the young.  Yesterday, I had more time to observe and got my answer.  The juveniles are helping their parents feed the nestlings.

The efforts I observed were not always smooth, as in, multiple attempts to fly into the predator guard, and near collision with a parent while exiting the nest, but as the day progressed, the juvenile efforts became more and more efficient.  Not only were they feeding  young, they were also removing fecal sacs.

From time to time, the male took charge of activity, issuing strong warning notes that caused a juvenile to change directions in mid flight.  Sometimes the warning seemed to indicate it wasn't safe to approach the nest.  At other times, the reason was not apparent, but his authority was clearly affirmed.

The juveniles respond differently to their parents in general now, rarely expressing themselves as fledglings eager to be fed, but more as family members heeding group hierarchy. Juveniles may display an open-mouth response w/o begging vocals if a parent lands too close.  The display seems to indicate submission or a reminder, 'I'm a baby', as seen in the image below.  The female, to the right, had just landed.  The juvenile displayed an open mouth for a few seconds and quickly departed.

While watching the juveniles bring food to the nestlings, there were also occasions when the juveniles just seemed to be behaving as juveniles.  For example, in the images below, you'll see two juveniles at the nest box at the same time.  Watch what happens as the second juvenile passes the first while entering the nest box.

As the day progressed, there seemed to be more and more harmony in the efforts, with as many as three family members lined up on a limb waiting for their turn to feed the nestlings.

The nestlings are thirteen days old today.  Eastern bluebirds generally fledge at 16-22 days, according to my monitoring guide (Cornell Bird Library Guide).  The first brood fledged at 18 days.  I checked the nestbox today for the last time pre-fledging and counted four beautiful nestlings, two males, one female and one whose gender I couldn't determine because the wing feathers were hidden under piles of sibling feathers.  When these nestlings fledge, the family will scatter initially, as the fledglings fly to high perches for safety.  If I'm lucky, they will later return to visit the feeder and the bird bath, and I'll have opportunity to see how siblings of different ages interact.              

Links and Resources:

This is the fifteenth post in my series on this bluebird family.  To see all of the posts visit the link, bluebird family.   The most recent post will be first.  Click "older posts" at the bottom of the page to see earlier posts.

Find instructions for making nest box predator guards by clicking the link.  These guards have worked to keep the 9" arm of a raccoon out and have prevented prowling cat predation, as well as snakes.  A 7-inch depth is recommended.  You may also find a version of these guards at the Wild Birds Unlimited store nearest you.

Coming up:  Fun visits with purple martins!

Linked to Bird Photography Weekly #151, a reminder to help conserve our world's birds.