Sometimes it’s obvious – a Carolina Wren nest in your front porch light or lawn mower. A Bluebird exactly where it should be, in a Bluebird box.
But other times, it’s harder to spot—a brood patch hidden under layers of feathers, or a dive bomb bop on the head that signifies “Clear outta’ here, I’ve got kids to protect!”
Breeding and nesting behavior can be seen everywhere in New York come late spring, if you train your eyes to look for it. These behaviors indicate birds are involved in mating and reproducing young. Once you start spotting the telltale signs, you can use your knowledge to contribute to community science efforts like the Breeding Bird Atlas! In fact, scientists rely on this information to understand where birds are nesting—as opposed to having to spot every single bird’s nest in person. Read more below, and check out the webinar recording of “An Inside Look: Whos Nesting Near Me?”, which explores these behaviors in-depth.
Breeding behavior doesn’t follow our human understanding of “it takes two to tango.” It can happen between two birds, two birds enticing one female, or a group attempting to impress one female.
Birds like the Ruby-crowned Kinglet have a crest. Most of the time its smooth, but when agitated by another male intruder to their territory (or human, or cat) they will hop around and flash their crest to signify that they don’t like you in their area – they are big and bad and you should beware!
Male birds may build a nest, or start building a nest to entice a female to the general nest, but the female often chooses the final nesting site. If you notice a bird coming or going, it’s doesn’t necessarily mean chicks are present. It could be a bird, like this Prothonotary Warbler, checking out a potential nesting site.
It’s a familiar sight thanks to Thanksgiving—turkeys (“toms”) with their tails fanned out. Turns out turkeys don’t look this way all the time! When Wild Turkeys are attempting to breed with a female, they will strut around with their tail fanned out, even sparring with other males to win the title of “most dominant.”
Hawks, eagles, crows, and Osprey are often seen being harassed by smaller birds. No, those smaller birds aren’t hitching a ride, they are hazing the bird they perceive as a predator out of their territory. Sometimes birds like cardinals, orioles, and bluebirds will go after their reflection in a mirror, believing it to be a competing male. (If you can discourage this behavior by breaking up the reflection with window decals, it’s helpful to the bird. Sparring with yourself is tiring and wastes important energy meant for breeding!)
This one is simple: if you’ve spotted a male and female together in the area where they typically nest, it is likely they are engaging in breeding. This Common Yellowthroat pair was spotted in a marshy area, the appropriate breeding habitat.
Confirmed breeding behavior hones in on clear evidence, from spotting an actual nest to a bird carrying nest material.
Nesting females like this Eastern Towhee will pluck off feathers in order to incubate eggs. Bird banders sometimes have to blow on a bird’s chest feathers to see its brood patch! Sometimes this is the only indicator scientists can find to confirm the bird is breeding!
What we can more easily notice is birds carrying nesting materials, from spiderwebs to grasses and mud.
Yes, birds need diapers too. You don’t get to see this behavior too often, but cavity-nesting birds like finches and bluebirds build their own diaper capsule that can be carried out of the nest. This reduces smells which attract predators and keeps the nest clean.
Now that you’re a breeding bird expert, you can help scientists learn what birds are breeding where, and whether they’re breeding successfully! Learn more about New York’s Breeding Bird Atlas here: https://ebird.org/atlasny/home
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Defense tactics: Dive bombing and broken wing displays
You may be recalling the earlier described mockingbird scenario and are all too familiar with that feeling. It has been observed that backyard birds and predatory birds will dive bomb to ward off potential threats.
It’s not just the backyard birds that use that tactic. Certain birds that nest on beaches, such as least terns and black skimmers, do so in colonies, or big gatherings. There can be hundreds or even thousands of people living in one colony. Even though they may be numerous, they are totally exposed to outside threats because they nest on the beach. If they approach you too closely, their team will attempt to dive bomb you.
Another well-known strategy employed by killdeer and other plovers is the display of broken wings. These species also build their nests on the ground, but they are left to fend for themselves rather than in large colonies. Their defense usually starts with warning calls, directed at you as well as to their chicks, telling them to hide. That’s the cue to turn around and give them some room. In the event that an individual or possible predator approaches the chicks or nest too closely, a display of broken wings will be showcased. This serves as a decoy to draw the danger away from the nest, making the adult seem like a simple mark.
Sometimes, though, it’s more difficult to identify—a brood patch concealed beneath layers of feathers, or a dive bomb bop on the head that says, “Get out of here, I have kids to protect!”
Birds carrying nesting materials, such as grasses, mud, and spiderwebs, are easier to observe.
Now that you’re a breeding bird expert, you can help scientists learn what birds are breeding where, and whether they’re breeding successfully! Learn more about New York’s Breeding Bird Atlas here: https://ebird.org/atlasny/home
Smaller birds are frequently observed harassing hawks, eagles, crows, and osprey. No, those smaller birds are chasing the bird they believe to be a predator out of their territory, not hopping on board. Orioles, cardinals, bluebirds, and other birds occasionally chase after their reflection in a mirror, thinking it to be a rival male. (It’s beneficial to the bird if you can stop it by using window decals to break up the reflection. Fighting with oneself is exhausting and squanders vital energy that should be used for procreation!
Based on concrete evidence, such as observing an actual nest or a bird carrying nest materials, confirmed breeding behavior is determined.
First, let’s talk about why.
Many people consider spring to be the start of bird nesting season. With this comes a lot of preparation. These birds may be constructing nests, returning from a protracted flight from their wintering grounds, or searching for a partner. Many species invest significant time and energy in ensuring a successful nesting season. To ensure that their preparations don’t go to waste, they must maintain a high state of alert and employ dramatic defense strategies to protect their territory, offspring, or both.
FAQ
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