By Eleanor Diamant and Dr. Pamela Yeh, UCLA
Junco Adaptation to Cities in the Digital Age
The Dark-eyed Junco, a small but mighty bird, has been doing well in cities despite all of the disturbances that people (and their cars, buildings, and pets) cause.
Within Southern California, juncos first colonized the city of San Diego in the early 1980s. They have more recently colonized cities up the California coast, landing in Los Angeles in the 2000s, and in Santa Barbara likely within the last 10 years.
In Dr. Pamela Yeh’s lab at UCLA, we have been banding and studying junco populations in Santa Barbara, East Los Angeles, West Los Angeles, and San Diego. We are determining how the junco populations have adapted to life in a city, and whether they have adapted similarly or differently across the different cities. At UCLA, we have been following their lives for the past two and a half years, finding where they nest, and determining the success of each of our uniquely banded (and named!) birds. Using this data, and incorporating citizen-science data from NestWatch, we can determine how different behaviors affect success within the UCLA population as well as the larger breeding population.
Thanks to NestWatch, we have been able to move nest monitoring into the digital age and facilitate nest checks across a large team of undergrads and graduate students. Samuel Bressler, our Junco nest-hunting king and Master’s student, brought NestWatch into the fold in the middle of our first field season in 2018. Through it, we can easily keep up to date, determine who needs checking, and facilitate nest checks when different members of our team are checking or banding chicks. We are also excited at the prospect of adding our data from more than 150 nests to the large pool of data collected by the NestWatch community.
Juncos in the City: Exploring New Heights (and Depths!)
Though classified as “ground-nesters,” 13% of junco nests were found to be above ground level between 1998-2002, including one in a bicycle helmet. Yet at UCLA, the juncos appear to build even more of their nests off the ground. Not only that, but we’ve found our juncos nest in all sorts of weird places throughout campus. One member of the UCLA grounds crew found a junco nest in a construction hat hanging from a wall hook inside a shed in an underground parking lot! We’ve also found junco nests on cardboard boxes in a parking lot, under a strewn cardboard box in a gutter, on an electrical box 3 stories underground, 50 feet up in a palm frond, in window shutters, in pseudo-cavities in trees, on fire alarms, and on windowsills. Without a doubt, juncos’ nesting behavior is breaking new ground as these birds continue to nest in our cities.
Interestingly, a dive into recordings of junco nests have revealed some quirky behaviors. NestWatch has recorded instances of Dark-eyed Juncos nesting in nest boxes. Older literature reveals even more diversity. The UCSD juncos were not the first ones to make their way out of the mountains and into campuses. Dr. John Snyder found two juncos nesting at Stanford University in 1904. These juncos built their nest off the ground in the loose bark of a Eucalyptus tree. Sadly, Dr. Snyder collected that first nest, eggs, and one of the adult juncos in the pair as specimens before the eggs hatched, so we will never know if the pioneering pair would have been successful. Juncos were also noted to nest in old woodpecker holes and tree cavities more than a hundred years ago. They had even been found to nest in tin cans throughout the early to mid 1900s.
Juncos nesting in cities are not only choosing nest sites differently, but they are also timing their breeding season differently. San Diego juncos breed for twice as long as their mountain counterparts, beginning to build nests in early March and breeding until late July/early August. Mountain-dwelling juncos on the other hand, begin nesting in May and end their breeding season in late July. We have noted similar patterns between the UCLA juncos and the UCSD juncos.
As we modify our landscapes in new ways, how is this adaptable bird changing with it? How does first egg date relate to climate and to urbanization? And how much of their behavior in cities differs from their behavior outside of cities?
A Call for Citizen Science—This Year More Than Ever
As we continue to face the crisis of COVID-19, many of us are being restricted to our homes and neighborhoods. Using this time to truly get to know the birds we share our communities with can not only bring some peace to our own lives and teach our children about our ecological community, but also help researchers determine how our environments are affecting bird nesting behavior.
Most members of our junco team have made the difficult decision to remain at home (after graduate students and the lead scientist obtained special permission from UCLA to continue research). Team leader Dr. Pamela Yeh will continue working alone in the field. Knowing that one person cannot substitute for two Ph.D. students, three Master’s students, and a dozen undergraduates, we would like to use NestWatch to coordinate remotely between researchers and shift how we do research and what data we gather. Thanks to NestWatch and the citizen-scientist community, we are hoping that together we can bolster our data on junco nesting–and other birds’ nesting behavior–across their ranges.
Specifically, we’re asking NestWatchers who live within the breeding range of any Dark-eyed Junco subspecies for help collecting data on junco first egg dates, nest height above ground, and nest success, including in urban and suburban areas. As human disturbance dramatically declines in many urban areas, we have an opportunity to learn how our landscapes are affecting bird nesting behavior and their success within the urban environment. Although we can’t visit our normal study sites, the UCLA team will also be searching for nests at our homes, as local ordinances allow—and we invite you to join in, if you can.
Please note that we urge you to put your own safety first and to comply with any local or state orders regarding outdoor activity.
“Specifically, we’re asking NestWatchers who live within the breeding range of any Dark-eyed Junco subspecies for help collecting data on junco first egg dates, nest height above ground, and nest success, including in urban and suburban areas.”
If you’re a NestWatcher with access to outdoor space, you can look for junco nests around your home in grasses and ivy on the ground, but also in places like flower pots, hanging baskets, under a tarp, on a forgotten door wreath, and in low rock crevices. Look for behaviors like picking up grasses and food items and follow the adults from a distance to their nest site. From all of us on the junco team at UCLA, we appreciate any nesting data you can submit during this difficult time.
Note: This post has been edited to provide more detail about the adjustments that UCLA researchers and students have made to their fieldwork schedules in response to COVID-19 shelter-in-place guidelines.