Updated May 27 at 11:35 a.m.

In all his years watching the pigeons who take up residency is in his hometown of Worcester, Bill Hughes says there’s one thing he’s never seen: a chick. And for decades he’s asked anyone willing to listen whether they have seen one — to no avail.

It's long mystified him. So much so that he has taken to asking his question of friends, even strangers.

"And they all stop and they look at you like you’re an idiot. And then they think, and they go, 'Ya know, now that you mention it, no,'" he reflected. "I said they can’t be born full grown. Where are they?"

For an answer, Bill turned to me, and I turned to Dr. Elizabeth Carlen, a postdoctoral researcher at Washington University in St. Louis who studies urban wildlife.

She began by confirming the obvious: "Baby pigeons do exist," she said.

Whew.

They are born, in most cases, two at a time to adult pigeons, who Carlen said are remarkably good at family life.

"Pigeons are mating for life," she said. "They’re continuing to go back to the same partner to mate with."

A pigeon couple has, on average, 13 babies a year — so they know how to keep the fire burning during those long-term, committed relationships.

"The male will puff out his chest and fan out his tail feathers and strut for the female," said Carlen. "This helps keeps up those pair bonds as they continue to mate and raise offspring together."

And Carlen said they truly do raise them together. Egg incubating and brooding duties are shared, with the father taking the day shift and the mother working overnights. Feeding the young is also a two-pigeon operation, as both the male and female produce milk.

"They feed the chicks with something called 'crop milk,' which is milk that's produced in their crop that is kind of cottage cheese–like and is really, really rich in protein and allows those babies to grow up very, very fast," she explained.

As for those babies … well, there’s really no sugar-coating it.

Baby pigeons
Baby pigeons in a nest.
Julie Kitzes/Getty Images Moment RF

"They’re not exactly the cutest," she said. "They have weird limb lengths and they're pretty pink when they're born. And then they have these tiny yellow feathers, but the feathers aren't really covering them."

The upshot, said Carlen, is that "if you came across a baby pigeon, you might not know that it’s a baby pigeon."

Still, it’s not easy to just come across one. Baby pigeons stay in the nest for about a month after they hatch, and they are essentially fully grown when they leave. So, the best place to see one is in a nest. The problem is that pigeons don't really like their nests to be found.

"Pigeons like to nest in kind of crevices and kind of hidden away places. Places hidden away from the wind and the sun and predators," said science writer and cartoonist Rosemary Mosco, author of "A Pocket Guide to Pigeon Watching."

I met up with Mosco in Cambridge’s Porter Square — a popular spot for pigeons — to do some nest hunting.

Mosco explained that the bird's nest-building habits are not only practical, but also a product of their complicated backstory.

"The wild ancestors of our feral pigeons lived in holes in cliffs," she said. "So really kind of out-of-the-way places."

Pigeons are descended from the wild rock dove, a bird native to parts of Eurasia and North Africa that was domesticated as many as 10,000 years ago. Domesticated pigeons were brought to North America by European colonists as pets and as a food source. Those domesticated birds eventuallly made their way back into the wild and have flourished in urban areas in part becasue the manmade landscapes are not that unlike their forebearers' homes.

Like their cliff-dwelling ancestors, pigeons nest on flat surfaces. Building ledges and the tops of air conditioning units are popular, as are the undersides of bridges and highway overpasses.

The nests are often rudimentary — sometimes just a few scattered sticks — and usually pretty close to where flocks hang out. Mosco says the best way to find one is to listen for it.

"There's a thing called the 'advertising coo,'" she explained, "where when a male is at his nest and kind of showing off, 'check out this cool spot I found,' he'll go 'woo woo.'"

Or you might hear the babies themselves, a high pitched "chirp," which is how we spotted a nest on top of a structure along the red line tracks below us.

"They're quite loud," said Mosco. "Once you start hearing it, you'll realize there are pigeon nests everywhere you go."

Still, tracking down a nest doesn’t mean there will be babies in it. And even if there are, you might just see a parent sitting on them, which is as close as we got to seeing a baby on our hunt in Porter Square.

But while infants are elusive, Mosco says fledglings just out of the nest are actually pretty easy to spot, if you know how.

As we gazed across a flock of a few dozen pigeons perched neatly on the roof of the Porter Square T station, Mosco pointed out a juvenile pigeon right there among them, hiding in plain sight.

She walked me through the three ways you can identify a youngster (and binoculars definitely help):

  1. The eyes. Adult pigeons have orange/yellow eyes. Mosco said a fledgling's eyes are more of a pale brown.
  2. The shine. An adult has quite shiny plumage, especially around the neck. Mosco says with young pigeons, "the plumage is duller, there’s not as much shine on the neck."
  3. The beak bulb. Pigeons have a bulbous area at the top of their beak called a cere. And while the pigeons just out of the nest also have this burb, it's much smaller. "So it's basically not trying to show off like it’s a fancy pigeon, out on the town, looking to court."

Mosco says paying close attention to pigeons, whether it’s to spot a nest, identify youngsters or just because they’re around around is always time well spent — at least in her book.

"They reward a closer look," she said. "and they also have a lot to tell us about our history and the way we treat, treat birds and the way we treat animals. There’s just a lot more going on than you would immediately think when you walk by a bunch of these awkward little gray birds."

And one final note about local pigeons, specifically. Dr. Carlen ran a study a few years back that showed that the pigeons in Washington, D.C., Baltimore, Philly and New York City are all closely related, but the ones here Boston are genetically unique. As for why, she said all indications are — no joke — that the journey through Connecticut is just as much of a headache for pigeons as it often is for human drivers.

Correction: A previous version of this article how many babies pigeon couples have each year.

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