A Squirrel Enthusiast’s Guide to Squirrels in New York City

This project examines a dataset detailing observations of squirrels made by a New York data enthusiast with the help of over 300 volunteers. Over a period of two weeks, these observers counted the number of squirrels they saw around the city, taking note of their locations, identifying features, and various behaviors–what they were doing, how they interacted with humans, and even the sounds they made.

This project was created by Raleigh Halbert, Hailey Hoang, Yasmin Leite, Alexa Whitman, and Qiong Wu.

Where are the squirrels? How approachable are they? How can we feed the most of them?

These graphs show the locations of where squirrels have been observed around Central Park, the concentration of the population in each area, and what type of behaviors they displayed.

These maps can be helpful for squirrel enthusiasts to determine the best place to feed squirrels. They would want to go to the area of the park where squirrels are:

  • least likely to run away from them

  • most indifferent

  • seen eating the most

  • seen foraging the most

Does the length of the day affect how likely squirrels are to be seen?

This bar and line chart illustrates the relationship between daily squirrel sightings and daylight in New York City. This is for October 6th to October 20th 2018. The pink bars represent the number of squirrel sightings each day, while the orange line shows the number of daylight hours. Since squirrels are typically active during daylight hours (Enviroliteracy, 2025a), we explored whether decreasing day length affected sighting frequency.

  • Day lengths were calculated using sunrise and sunset times gathered from Timeanddate.com.

  • Daylight hours gradually declined over the two-week period as the end of daylight savings approached.

  • Squirrel sightings also generally decreased, though the trend is uneven with some spikes.

  • The drop in sightings may suggest a relationship between shorter days and reduced squirrel activity.

  • Due to limited data, we can’t make strong conclusions.

  • Further research with larger data sets with controls would be needed to confirm any connection.

What is the relationship between squirrels’ primary fur color and their behavior toward humans?

This stacked bar chart illustrates the relationship between squirrel fur color and their behavior around humans. Three main behaviors were tracked for this analysis: approaches, indifferent, and runs from. The chart shows the percentage of each behavior among groups of squirrels categorized by their dominant fur color which could be black, cinnamon, and gray.

  • Most squirrels, despite their primary fur color, displayed indifference towards humans.

  • Black squirrels had the highest rate of “runs from,” suggesting that squirrel feeders may prefer to place food on the ground near squirrels with black primary fur color.

  • Cinnamon squirrels had the highest levels of “approaches” relative to other groups, which means that feeders may be able to feed them directly by hand.

  • Overall, squirrels are animals and there is no promise that they will act a certain way, feeders should use their best judgement

Are squirrels more active at different times of the day?

shift activities totals
AM Chasing 131
AM Climbing 340
AM Eating 296
AM Foraging 601
AM Other_Activities 212
AM Running 327
PM Chasing 148
PM Climbing 318
PM Eating 464
PM Foraging 834
PM Other_Activities 225
PM Running 403

This grouped bar chart shows the number of times squirrels do a certain activity in the morning (AM) and afternoon / evening (PM).

However, there is a limitation with this. There isn’t a specific time for each observation, instead, it’s denoted as either AM or PM. So, we cannot truly tell when exactly the squirrels were more inclined to engage in a certain activity.

Based on their calls, where do squirrels seem to feel the most threatened?

Squirrels have three common types of alarm calls used to warn each other of danger: kuks, quaas, and moans (Enviroliteracy Team, 2025). Kuks, which resemble like the barks of a small dog, are most common, and are used to signal general threats such as the presence of humans. Quaas are used to alert other squirrels to ground predators such as foxes or dogs, and moans indicate that an aerial predator (bird) is nearby, and warn other squirrels to seek cover.

We created a dot density map to show the distribution of alarm calls across the Central Park area. Across all observations, there were 102 kuks, 50 quaas, and 3 moans recorded. Since kuks indicate the least immediate danger, they are denoted with the lightest color in the map to the right, while quaas and moans are represented by darker colors. Thankfully, the majority of alarm calls observed are kuks, implying that these Central Park squirrels are not often in immediate danger. However, there were still a significant number of quaas observed, which could be due to the presence of dogs taken on walks in Central Park.

This dashboard was created using Quarto in RStudio, and the R Language and Environment.

The data used to create this dashboard were downloaded from

  • NYC squirrel census data
  • Central and Prospect Parks shapefiles

  • Sunrise and sunset times: use the suncalc package (Thieurmel, Bastien, and Timothée Giraud. suncalc: Compute Sun Position, Sunlight Phases, Moon Position and Lunar Phase. R package version 0.5.0, 2019. CRAN, https://CRAN.R-project.org/package=suncalc. )

The code used to download the squirrel data is as follows:

nyc_squirrels <- readr::read_csv(“https://raw.githubusercontent.com/rfordatascience/tidytuesday/main/data/2019/2019-10-29/nyc_squirrels.csv”)

References Information

David. (2022, December 21). Squirrel noises and sounds: Barks, screams, chirping—What do the calls mean? Squirrels at the Feeder. https://www.squirrelsatthefeeder.com/what-sounds-and-noises-do-squirrels-make-and-what-do-they-mean/

Deadlock, J. [Jed Dedlock]. Grey squirrel alarm call [Video]. YouTube. https://www.youtube.com/watch?v=8b-2TFrx3fg

Enviroliteracy Team. (2025a). “What do squirrels do after dark?” Enviroliteracy. https://enviroliteracy.org/what-do-squirrels-do-after-dark/#:~:text=Generally%2C%20squirrels%20are%20not%20active%20after%20dark.%20As,primarily%20seek%20shelter%20and%20rest%20in%20their%20dens..

Enviroliteracy Team. (2025b). “What is a squirrel warning call?” Enviroliteracy. https://enviroliteracy.org/what-is-a-squirrel-warning-call/.

Robinson, D. [David Robinson]. (2019, November 1). Tidy Tuesday screencast: Analyzing squirrels in NYC [Video]. YouTube. https://www.youtube.com/watch?v=6GV9sAD6Pi0

Videniteo Trailblazers. (2021, July 21). Squirrel kuk” sound [Video]. YouTube. https://www.youtube.com/watch?v=2jYugSon5qI

Software and Packages

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Bache S, Wickham H (2022). magrittr: A Forward-Pipe Operator for R. R package version 2.0.3, https://CRAN.R-project.org/package=magrittr.

Dancho M, Vaughan D (2025). tidyquant: Tidy Quantitative Financial Analysis. R package version 1.0.11, https://github.com/business-science/tidyquant, https://business-science.github.io/tidyquant/.

Kunst J (2022). highcharter: A Wrapper for the ‘Highcharts’ Library. R package version 0.9.4, https://CRAN.R-project.org/package=highcharter.

Neuwirth E (2022). RColorBrewer: ColorBrewer Palettes. R package version 1.1-3, https://CRAN.R-project.org/package=RColorBrewer.

Posit team (2024). RStudio: Integrated Development Environment for R. Posit Software, PBC, Boston, MA. URL http://www.posit.co/.

R Core Team (2024). R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/.

Rinker, T. W. & Kurkiewicz, D. (2017). pacman: Package Management for R. version 0.5.0. Buffalo, New York. http://github.com/trinker/pacman

Robinson, D. (2019, November 1). Tidy Tuesday screencast: Analyzing squirrels in NYC [Video]. YouTube. https://www.youtube.com/watch?v=6GV9sAD6Pi0

Vanderkam D, Allaire J, Owen J, Gromer D, Thieurmel B (2018). dygraphs: Interface to ‘Dygraphs’ Interactive Time Series Charting Library. R package version 1.1.1.6, https://github.com/rstudio/dygraphs.

Wickham H, Averick M, Bryan J, Chang W, McGowan LD, François R, Grolemund G, Hayes A, Henry L, Hester J, Kuhn M, Pedersen TL, Miller E, Bache SM, Müller K, Ooms J, Robinson D, Seidel DP, Spinu V, Takahashi K, Vaughan D, Wilke C, Woo K, Yutani H (2019). “Welcome to the tidyverse.” Journal of Open Source Software, 4(43), 1686. doi:10.21105/joss.01686 https://doi.org/10.21105/joss.01686.

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Yihui Xie (2015) Dynamic Documents with R and knitr. 2nd edition. Chapman and Hall/CRC. ISBN 978-1498716963

Yihui Xie (2014) knitr: A Comprehensive Tool for Reproducible Research in R. In Victoria Stodden, Friedrich Leisch and Roger D. Peng, editors, Implementing Reproducible Computational Research. Chapman and Hall/CRC. ISBN 978-1466561595

Zhu H (2024). kableExtra: Construct Complex Table with ‘kable’ and Pipe Syntax. R package version 1.4.0, https://github.com/haozhu233/kableExtra, http://haozhu233.github.io/kableExtra/.scale_fill_paletteer_d(“lisa::AmedeoModigliani”)