Expert consulted: 
Every spring, well-meaning gardeners and bird lovers accidentally harm nesting birds without realizing it. From checking on nests too often to trying to “rescue” baby birds, common backyard habits can put eggs and hatchlings at risk. To learn how to safely coexist with nesting birds this season, we spoke with Holly Grant, project assistant at the Cornell Lab of Ornithology’s NestWatch program.
What Is the #1 Threat to Nesting Birds?
According to Holly, it’s most likely nest disturbance since pets and humans can scare birds off their nests, which risks nest abandonment. According to Holly, “Too many ‘scares’ and the adults will move on to try nesting somewhere else.”
Keep Your Distance from Nests
Per Holly, “Not only can birds be scared off their nest if humans get too close, but if folks are spending too much time near a nest, such as sitting out on a porch, using a grill, or otherwise actively spending time too close to a nest, the adult bird might be too nervous to return to their nest, which could be catastrophic to eggs that need to be incubated or young that need to be fed.”
Also, Holly says to never move a nest to a less-trafficked area. “Birds won’t understand that the nest has moved—they just see that it’s not where they left it and assume a predator got to it,” says Holly.
Know When to Intervene and When to Walk Away
The first thing to do is to figure out if the baby bird is a nestling or a fledgling.
Per Holly, “Fledglings are feathered and capable of hopping or flitting, with toes that can tightly grip your finger or a twig. These youngsters are generally adorable and fluffy, with a tiny stub of a tail.” While fledglings may look helpless, they are still under the care of their parents and are typically doing just fine.
“Nestlings are sparsely feathered and not capable of hopping, walking, flitting, or gripping tightly to your finger,” Holly says. These are birds that are too young to be out of the nest.
Should I Put the Bird Back in the Nest?
If you know that it’s a nestling and you can find the nest nearby (they are often well hidden), put the bird back inside as quickly as possible, says Holly. If the nest is destroyed, you can make one (details on that here) and monitor to see if the parents come back.
When Should You Contact a Wildlife Rehabilitator?
According to Holly, “Only contact a rehabilitator if you find an injured bird or if it is a nestling and you haven’t seen an adult visit the bird within an hour or two.”
How to Safely Keep Tabs on a Nest
“If you’d like to keep tabs on the nest, such as recording data for NestWatch, research shows that visiting the nest once every 3 to 4 days at most (about 1 to 2 times per week) is just enough to collect meaningful data while keeping disturbance low,” per Holly.
Holly says, “Always minimize the time you spend near the nest to reduce stress and to help keep the nest from being noticed by predators. Crows and jays, which eat nestlings and eggs, are smart and may get curious if you’re spending too much time in one area of your yard!”
NestWatch has a good monitoring manual with loads of details, but here are a few quick pointers: When checking on a nest, approach it from a different angle every time; check in the afternoon, never in the morning; don’t check the nest when it’s raining or cold; never spend more than 1 minute at the nest on each visit; and never handle the eggs or nestlings.
Keep Pets Leashed and Cats Inside
Per Holly, “Research published in 2015 found that cats were the #2 cause of bird loss, behind habitat loss and degradation. Cats are estimated to kill more than 2.4 billion birds annually in the U.S. and Canada. While bells on collars do help, the best way to help birds is by keeping cats indoors or creating an outdoor ‘catio.’ Any pet that is off-leash during fledging times may also chase after fledglings, which hop and flutter around on the ground like toys.”
And if you are worried about other predators, like raccoons and snakes, getting into your nesting box, Holly recommends using a cone or stovepipe baffle for birdhouses that are mounted on poles. Noel guards and entrance hole extenders can also help, but Holly notes that there is no design that is 100 percent predator-proof. Predators are a normal part of life for birds, but these measures can help increase nesting success for nests in boxes.
Holly Grant is a Project Assistant at the Cornell Bird Lab on the NestWatch project, and has expertise in nesting birds, feeder birds, and bird feeding strategies among other things. She holds a B.S. in Conservation Biology. You can find out more about Holly on her staff bio page.
