You scared baby birds out of their nest, oh no! Will they be okay?

You’ve gone to peek at a nest. For a moment, all the little feathered heads regard you with large, dark eyes—and then in a flurry and a tumble they are out of the nest, running every which way along the ground, and their parents are scolding you and swooping among their babies in apparent panic. Oh no! Will the babies be okay?

2486466297_c685665d69_z

Scary human! I’m outta here. (Photo by Timothy K Hamilton: https://www.flickr.com/photos/bestrated1/)

This is possibly the question I am asked most frequently. Sometimes the inquirer has managed to catch a few of the babies and replace them in the nest, only for the babies to promptly hop back out. Other times the babies have swiftly vanished, and the inquirer—often someone who has watched the nest over the course of weeks, growing attached to their fluffy neighbors—is left, quite suddenly, with silence and absence and a gnawing guilt.

Baby birds fledge—leave the nest—when it is safer for them to be out of the nest than to be in it. If they are undisturbed, they may stay in the nest for a long time, growing out their flight feathers so that when they do fledge, they will be mobile and able to escape predators. However, they are able to leave the nest much earlier, if they are disturbed. Juncos, for example, may stay in the nest as long as 15 days after hatching; but if something scary disturbs them, they can wobble-run out of the nest as early as day 7. Baby birds may perceive a peeking human as a potential predator, and decide to flee rather than wait and see if the human is planning to eat them. When fledging occurs due to human disturbance, we call it “force-fledging.”

34400397391_5e76daf93d_z

That sounds terrible. You should feel terrible. (Photo by bramblejungle: https://www.flickr.com/photos/bramblejungle/)

Ornithologists have been worried about force-fledging for a long time, because no one force-fledges more baby birds than ornithologists. It’s an unavoidable byproduct of searching for, and checking on, hundreds of nests: sometimes a nest is older than you expected, or the babies are more on-edge than usual, and you accidentally force-fledge the nest. In the case of my junco field work, this presented me with a dilemma: I needed to band and collect blood from the babies, and they needed to be a certain minimum size for that—8 days old, at least. If I banded them at 8 days, they were usually little enough to stay in the nest afterwards; but sometimes they decided to fledge, and then they were out there, fledged, at a fairly young age. Alternatively, I could wait until they were just about ready to fledge anyway—13 days—at which point they always fledged after we banded them, but at least we knew that they were just about at fledging age anyway.

For a long time, there was no way to know how bad force-fledging was. The babies fledged, and you hoped they were okay. Recently, however, the development of tracking technologies small enough to be attached to baby birds has allowed researchers to find out exactly what happens after baby birds are force-fledged.

2564339953_08475986f6_z

We die, probably. Don’t forget to feel terrible. (Photo by Dave_S.: https://www.flickr.com/photos/david_e_smith/)

Streby et al. (2013) were radio-tracking baby Ovenbirds and Golden-winged Warblers to find out what affected their survival. The researchers weren’t planning to study force-fledging; but, just like my juncos, their baby birds sometimes fledged after the researchers had attached the transmitters, so they ended up with data that let them ask that question. They had some baby birds who force-fledged at earlier ages than they would naturally fledge; some babies who force-fledged at the usual fledging age; and some babies who didn’t force-fledge, but fledged naturally later at the time of their own choosing. The transmitters allowed the researchers to track the survival of all of these babies.

Their results were surprising: force-fledged baby birds did not have lower survival than naturally fledged babies. In fact, in the Ovenbirds, the force-fledged babies had higher survival!

35090560331_bc4523105a_z

Wait, what? (Photo by Eric Ellingson: https://www.flickr.com/photos/ericellingson/)

This doesn’t mean that you should go around force-fledging all the baby birds you can find to increase their survival. Rather, the researchers interpret this as showing that the baby birds who force-fledge are ready to fledge, and the ones who don’t, aren’t. The force-fledged babies, then, were further along in their development—more ready to leave the nest—than the babies who didn’t force-fledge. Babies who are further along in their development at a given age are inherently more likely to survive, and force-fledging doesn’t seem to do any major harm to them.

35078753401_0abb725c82_z

Because we are super tough. (Photo by Robin Horn: https://www.flickr.com/photos/powerkey/)

There are some caveats to this finding. Crucially, the researchers were only moderately disturbing the baby birds: they handled them and attached transmitters, but strove to minimize the birds’ stress and put them back in the nest afterward. Their results will not necessarily apply to baby birds who force-fledge due to a major disturbance, like an attacking dog or a roaring leaf-blower. Too, the researchers did not attach transmitters to any very young baby birds: their “prematurely force-fledged” babies were still fairly well-grown, with feathers and working legs. A major disturbance that causes very young babies to fledge—like the cow who trampled one junco nest I monitored—will definitely reduce the survival chances of those babies.

But if you peeked at a nest, and the babies bolted? They were probably ready to go, and their survival chances are probably not any worse for your peeking. You don’t need to feel guilty. (You do need to make sure that any pet dogs or cats you have are kept away from the area for the next week, while the babies are still grounded and vulnerable to predators.)

19127115464_6b5d0da1ed_z

Don’t be ridiculous. I am vulnerable to nothing. (Photo by Guttorm Flatabø: https://www.flickr.com/photos/dittaeva/)

Reference:

Streby HM, Peterson SM, Lehman JA, Kramer GR, Iknayan KJ, Andersen DE. 2013. The effects of force-fledging and premature fledging on the survival of nestling songbirds. Ibis 155:616-620.

16 thoughts on “You scared baby birds out of their nest, oh no! Will they be okay?

  1. Another reason not to use leaf-blowers– ever! Could you give species of all these fledglings for those of us who can’t tell? Thank you.

  2. What a great and inciteful post and I adore your captions. We loose baby birds. Somehow they end up out of the nest and we find little bodies in the garden. Too late often. They are tiny still with their big yellow mouths. Not sure what’s happened.

    • Oh no! If they have feathers, they probably fledged naturally but then got caught and killed by a cat. (Cats often don’t eat what they kill.) If they are still naked-pink, then perhaps they are fleeing a predator at the nest MUCH too early, and then dying. In any case that sounds distressing, I’m sorry!

  3. It’s good to know the survival rates are similar. I do breeding bird monitoring for the forest preserve and also monitor for Project Nestwatch. I’m always a little nervous about causing an early fledge.

  4. Thank you for a very interesting article. I too loved the clever captions. I do not have any nests this year yet (that I know of anyway) but am always on the lookout.

  5. I really enjoyed this post. We try to keep from bothering hatchlings, and I am here most of the time to run off possible predators. Still, each year I find a few that didn’t make it.

  6. Thanks for the update! My robins come back every year in a hanging plant in my front window. My family and I love watching nature take course right from our front window – and we are always concerned once the fledglings leave the nest – more often forced-fledged by the opening and closing of our front door! Thanks for your posts.

  7. Finding this post made me feel SO much better. This is the first time I have had experience with a bird’s nest. She decided to make one on top of the light fixture outside of my front door. I went to peek on the babies tonight by opening the front door and they got scared and flew all over the place. One actually flew into my house. I was thankfully able to put gloves on and coerce it into my hand. It trusted me enough to stay in my hand until I was able to bring it outside and place it back into the nest. Mom came back and fed him. But there have been no signs of the other 2. I felt so guilty until I read this post about force fledging. Thank YOU!

  8. I am so happy to find this post. There seemed to be nothing else even closely related to a bird leaving the nest due to peeking. I wish I had read it sooner, and I wouldn’t have been peeking. Not sure what kind of bird it is, but they made a nest in my xmas tree on my balcony and I’ve been feeding the mom and dad daily and every three days or so, peeking at the eggs, and then the chicks. I never touched them, just a little peek-a-boo. I didn’t know it would cause fledging, or even what fledging was :-( Today before work, it happened, after giving some seeds to mom or dad… just a little peek, and eye contact with a bird that wasn’t a little fuzzy mess like the last time I looked, but rather an actual bird, and in an instant, all three birds vanished in a flurry (all the babies) and I spent an hour trying to find them and return them to the nest (and did one or two of them or one twice…) but they just flew out right away. I really hope they survive. I feel so bad. If I am blessed with a nest next year, I won’t be peeking once I know there are babes in there. I wish I knew what kind of birds they are and I hope they are okay. At least it’s not too cold tonight!

    • It doesn’t sound like you caused any harm – if they were that good at flying out of the nest (several times!) they should be fine.

      Maybe try searching “Common backyard birds in [your location]” and see if you recognize the parents? If they were eating seeds then they aren’t robins or grackles, two of the most common open-cup nesting birds in the USA. Chickadees eat seeds but nest in holes, not an open-cup nest like you describe. House Finches are a possibility – they eat seeds and like to nest in conifers. Search House Finch and see if that looks right?

  9. Thank you for the article. I was just walking out of the barn, looked up at the overflowing nest filled with four baby robins, and craziness followed. All the babies flapping, fluttering and the mother robin yelling at me. What a terrible start to the day. I didn’t know what to do so just came back in my house on the verge of tears with a huge pile of guilt on my shoulders. Your article really helped me realize they must have been ready to go. The mother is out in the yard with them now. I hope the beautiful little ones will be okay.

  10. I needed to read this today. I disturbed a nest of baby juncos yesteday that we’ve been monitoring in the tall grass of our yard. I just wanted a peek and when I did, they all scattered to the bushes at the edge of yard. I felt so guilty. Mom and dad were very upset with me. I hope they survive but reading this, I think it was just about time for them to fledge naturally anyway. I estimate that they were 12 or 13 days old. On the bright side, now that I know they have fledged, I know to keep the dogs out of the yard for the next few days to give them more of a fighting chance. Thanks so much for this article and all writing you’ve done on juncos, I now am a big fan of these little guys.

    • Yes, if they fled at just a peek then they were ready! Thank you for thinking about the danger the dogs pose – giving the chicks a few days to grow in flight feathers will make a big difference in their chances of survival. I’m glad your junco nest has done so well!

  11. I’m really upset with myself because this morning I accidentally scared two baby robins out of their nest built in a large, dense thicket of vines outside our kitchen window. The first baby was born exactly two weeks ago today, so I assume the second was born the same day or a day later. So they were 13-14 days old, ready to fledge, I guess.

    I went out to take a couple of photos of them as I have occasionally over the past 2 weeks but today the babies became scared and flew slightly upwards and backwards into the vines facing the house. Both of their parents came rushing out of the woods, screaming. I went back inside immediately to avoid upsetting them further.

    I read that babies do not come back to the nest when they leave, and indeed they have not returned. A parent has come back twice in the next half hour or so, the first time with a worm in their mouth and the second time with no food in their mouth, sitting on the nest for a few minutes and then leaving again. I cannot see the babies anywhere. I’ve twice looked all around the vines, at the base of the vines, and in the window well under the vines and I can’t find them. I also don’t hear them. They’re not hopping around on the deck and I don’t see them in the grass. Maybe they are under the deck? Aside from the two times the parents came back to the nest, I haven’t seen any robins anywhere near the nest or deck or grass anywhere near the nest. We don’t have cats or dogs but there are many squirrels, chipmunks and rabbits in our yard. I hope so much they are going to be okay. We have trees, but all of them are maybe 25 yards away from the house so I don’t know if the babies could have flown that far. What do you think may have happened to them and where could they have gone? Is it possible that the parents have found the babies and are taking care of them?

    • I think it’s quite likely that the chicks are fine and the parents are taking care of them. They were old enough to fledge, and the parents’ upset reaction shows that the parents were paying good attention. The parents generally decide where they want the chicks to be and shepherd/lead them there; it’s possible that they’ve led them under the deck, or into any little clump of vegetation that provides a hiding spot. It’s also possible that the chicks are still in the vines, even though you searched: young robin fledglings like to sit COMPLETELY still, even if you get quite close to them, and that combined with their spots can make them just about impossible to see in vegetation. The parents will be sneaky about feeding them so as not to give away their hiding spot. I think you can expect to see very little of the robins for the next few days, and then gradually – if they haven’t moved on to a different location – to see them more and more as the fledglings get bolder.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s