Guest Post: Red, Redder, Reddest—How Living in the City Changes Cardinal Color

This post was contributed by Brooke Goodman, co-author of a recent paper in The Wilson Journal of Ornithology on the coloration of urban Northern Cardinals.

a smiling young woman with curly brown hair and glasses stands outside, holding a large red bird in one hand
Brooke holding a male Northern Cardinal. Photo by Dan Baldassarre.

The first time I held a Northern Cardinal, I immediately regretted it. A lot of fire fits in that tiny body, and they aren’t afraid to express it with a nasty bite to your finger. Then Dr. Daniel Baldassarre, his fingers covered in Band-Aids for bite protection, calmly handed me a miniature plastic finger for the cardinal to bite on instead of my own. At that moment I knew I had gotten myself into something fun. 

I was a freshman at the State University of New York at Oswego when I joined the Oswego Bird Behavior Lab, headed by Dr. Baldassarre. I knew I loved birds, but I didn’t really know what I could do with that passion. Lucky for me, Dr. Baldassarree needed students to work on various summer projects  focused on cardinals, which is how I found myself on the business end of a cardinal beak. We study cardinals not because we are masochists, but because we want to explore how urbanization is impacting birds, and cardinals are fantastic urban adapters. 

The cardinal’s willingness to breed in disturbed areas and its generalist nature make it well suited to persevere in the urban areas most birds steer clear of. They’re also ready and willing to take advantage of anything that the invasive species that thrive in disturbed areas have to offer. They are successful in both rural and urban areas, meaning we can study and compare  populations in both contexts. For the two summers that I worked on the project collecting data in the field, we spent our weeks traveling between our rural site in Oswego and our urban site in Syracuse, New York. 

Despite the eager adaptation of urban cardinals, they face more novel dangers than their rural counterparts. Light and noise pollution, feral cats, and windows pose severe threats to these birds. At the Bird Behavior Lab, we look at how these pressures may be altering cardinal behavior and what it could mean for their evolutionary future.We have investigated differences between populations in neophobia, disease, song, and most importantly for our recent paper in The Wilson Journal of Ornithology, carotenoid-based signals.

closeup of a red bird being held in a hand with bandaged fingers, a small plastic finger clamped in its bill
A male cardinal chomps on a plastic finger. Photo by Dan Baldassarre.

Color is clearly important to cardinals. Their bright red plumage is the star of many picturesque holiday cards. What many people aren’t aware of is the effort these birds put into maintaining that vibrant red. The “good genes hypothesis” tells us that ornaments may signal an animal’s condition; that is, a bright red cardinal is theoretically healthier, perhaps displaying to a potential mate that they will have super-healthy offspring. That may be why the metabolic energy they spend converting the yellow carotenoids in their environment into the red they deposit into their feathers is worth it. 

But urban cardinals have an advantage: one of the invasive species that thrives in their disturbed habitat, honeysuckle (Lonicera sp.), has naturally red carotenoids. Cardinals that eat honeysuckle berries don’t need to spend energy converting them from yellow to red, because they can go right into the bird’s feathers.

To examine carotenoid color patches, we looked at the bills (male and female), underwing feathers (female), and chest feathers (male) of urban and rural cardinals. We used reflectance spectrometry (chest feathers) and photos taken against color standards (bill and underwing) to evaluate the hue, saturation, and brightness of the color patches of interest. We also wanted to account for the sensitivity of the avian visual system during our analysis—birds can see a lot of things that humans can’t, including UV light, and we weren’t interested in seeing if humans could tell the difference between the rural and urban color patches, we wanted to know if a cardinal could! We also measured the bird’s body condition in the field by taking measurements of mass and tarsus.

Our results, in contrast to previous studies, found enhanced carotenoid-based signals in urban birds. Specifically, urban males had redder chest feathers in one year of our study and redder bills in every year. Urban females had more saturated underwing color than rural females in every year. Urban cardinals had significantly reduced mass-related body condition, but despite this poor condition, they could produce these presumably costly signals. The abundance of honeysuckle at the urban site may explain not only the enhanced signals, but the stability of the signals.The color of our rural birds seemed to undergo larger year-to-year fluctuations than the color of the urban birds. 

closeup of a female cardinal, held by a person gently spreading its wing fingers to compare them against a chart with squares of different colors
A female cardinal’s underwing area is compared against a color standard. Photo by Dan Baldassarre.

It is disturbing but fascinating to consider that urbanization could be disrupting traditionally honest signals in cardinals. For millions of years these birds may have been relying on plumage quality to choose mates, and now that signal is no longer reliable. Of course, there are other reasons why carotenoid-based signals could vary between the urban and rural populations, such as different lighting conditions, but honeysuckle availability is likely playing a role in this difference. 

Despite the challenges they face, I know our urban cardinals will persevere. We only visited our urban site once a week, but I always looked forward to it the most. I watched urban cardinals avoid feral cats, attempt to sing over obnoxious lawn mowers, and make nests in places so close to human activity that I could check them without leaving the busy trail. A moment I’ll never forget is watching (via trail cam) a cardinal nest get mowed down by an over-eager landscaper, only for the female to begin building a new nest just a week later. The toughness of cardinals reflects the harshness of the environments they choose to inhabit, and I am excited to explore more of these behaviors with the Bird Behavior Lab in the future.

WOS 2023 Call for Abstracts + Student Travel Awards Now Open

We are now accepting abstract submissions for our 2023 annual meeting, to be held June 20–23 at Muhlenberg College in Allentown, Pennsylvania! Please note that this year there are opportunities to present your research both in person and virtually, so we encourage you to consider participating even if you won’t be able to join us in Allentown.

The call for abstracts and submission form can be found here on the meeting website. The deadline to submit an abstract is March 1, and decisions will be sent to lead authors by mid-April. There is no virtual option for poster presentations, but if you are interested in presenting research and unable to attend the in-person meeting, please consider submitting an abstract for a virtual oral presentation. Students planning to present in person are also invited to apply for Student Travel Awards to offset their travel costs (deadline March 1).

We look forward to seeing you in June!

Research Grant Applications Open Until February 1

We are now accepting applications for all four categories of research grant offered by the WOS! Please note that the maximum award amount for each category has doubled for this application cycle. The four categories are as follows:

  • Louis Agassiz Fuertes Grants: Available to all ornithologists, although graduate students and young professionals are preferred. Any avian research is eligible. Up to two awards of $5000 are given annually.
  • George A. Hall / Harold F. Mayfield Grant: Limited to independent researchers without access to funds and facilities available at colleges, universities, or governmental agencies, and is restricted to non-professionals, including high school students. Any kind of avian research is eligible. Up to one $2000 award is given.
  • Wilson Ornithological Society Research Grants: Up to four awards of $3000 given annually for work in any area of ornithology. Two of these awards will be limited to research by Masters students.
  • Paul A. Stewart Grants: Preference is given to proposals for studies of bird movements (based on banding, radio or satellite telemetry, or similar methods) or an emphasis on economic ornithology. Up to four awards of $2000 are given annually.

See full details and application instructions here. We look forward to receiving your proposals!

Mentoring Program Applications Open + Other WOS 2023 Updates

For those of you who use this blog to keep up with the latest WOS news, there are several updates related to our 2023 meeting that we don’t want you to miss!

First, applications for our 2023 Mentoring Program for students and early-career professionals are now open. Participants in this program will receive free registration and travel funding to attend the 2023 WOS meeting; WOS membership for one year following the award; individual career mentoring; special professional development webinars and workshops; and networking opportunities to meet professionals from diverse fields. Please note we are also currently seeking volunteer mentors to participate in this program!

Second, in case you missed the announcement about this earlier this fall, this will be a hybrid meeting. We will have a full schedule of in-person events at Muhlenberg College in Allentown, Pennsylvania, but we will also be accepting abstracts for virtual oral presentations. The call for abstracts will open approximately January 1; please keep checking the meeting website for more details on the meeting’s virtual component as they become available.

Finally, proposals for symposiums, workshops, and special events are being accepted until January 31. Now is your chance to help shape the meeting program, so please check out the information on the website and send us your ideas! Prospective vendors interested in selling items or promoting a business at the meeting are also invited to contact Peter Saenger at to discuss arrangements.

We can’t wait to see you in Allentown (or online) next June!

Guest Post: Thick-billed Parrots of the American Southwest

This post was contributed by John A. Moretti, co-author of a recent paper in The Wilson Journal of Ornithology on the occurrence of Thick-billed Parrot remains at archaeological sites in the Southwest.

John Moretti during a study of avian osteology at the Museum of Texas Tech University. Photo courtesy of John A. Moretti.

The American Southwest conjures images of giant saguaro cacti, Gila monsters, and vast deserts. This landscape and ecology are a starkly different from the tropical forests and savanna of Central and South America, but preserved within the iconic ancient Native American pueblos of the American Southwest are the skeletons of Scarlet Macaws. Genetic and isotopic data show that the over 100 individual Scarlet Macaws found at sites such as Wupatki and Chaco Canyon were imported from Mesoamerica. Those highly intelligent, brightly colored birds appear to have held ritual significance for Southwestern cultures, and their transport into the region was part of an ancient cultural exchange of both objects and ideas. Scarlet Macaws are the most common member of the parrot clade (i.e., Psittacidae) in archaeological sites within the present-day United States, but other species, including Military Macaws, Thick-billed Parrots, and even a rare few parakeets also occur. Those species are generally regarded by archaeologists as exotic objects, transported into the region from present-day Mexico—but could one of them have originated much closer?

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