New York City has a long legal history in the fight against rats, with efforts to control the rodent population stretching back over a century, as highlighted in the city’s legal history of rat control. The city has implemented various measures, including new regulations from Mayor Eric Adams and DSNY Commissioner Jessica Tisch, such as a trashcontainerization strategy and even appointing a “rat czar”. But how big is the problem, when are New Yorkers most likely to encounter these unwelcome guests, and where are rats reported the most?

Thanks to NYC’s open data, we can analyze 311 rodent complaint data to uncover trends and patterns. In this post, I’ll use visualizations to explore when and where New Yorkers report rat activity, helping us better understand this ongoing issue.

---

1. Rodent Complaints Over Time: Analyzing Trends by Year

To start, let’s take a look at how rodent complaints have trended over the years. Using NYC’s 311 call data, I tracked the number of rodent-related complaints from 2010 to 2023. The visualization below shows a significant upward trend, with rodent complaints steadily increasing over time.

In 2023, we see the highest number of complaints on record—over 49,000 calls, nearly double the numbers from 2010. Interestingly, we see a temporary dip in complaints during 2020, likely linked to the COVID-19 lockdown when reduced human activity in the city during the pandemic may have affected both rodent activity and reporting behaviors. As residents returned to normal routines post-pandemic, complaints spiked once again.

Exploring Trends by Borough

By grouping the data by borough, we can uncover how the rodent problem varies across different parts of the city. The second visualization shows the trend of rodent complaints by borough, highlighting which areas have experienced the most significant increases in recent years.

Looking at rodent complaints by borough, Brooklyn stands out with the highest and sharpest increase in complaints over the past decade. By 2023, Brooklyn recorded nearly 18,000 complaints—more than doubling its numbers from 2010. Manhattan also shows a significant rise, though at a slightly slower rate, while Queens has steadily climbed, particularly after 2021. Interestingly, the Bronx experienced a noticeable decline in complaints since 2021, suggesting some improvement in rodent control efforts there. In contrast, Staten Island has consistently reported the fewest rodent complaints, with little fluctuation over the years. This variation between boroughs highlights the localized nature of NYC’s rodent problem, potentially influenced by differing sanitation practices and urban density.

Revealing Seasonal Patterns

Finally, changing the time bucket to a monthly view reveals seasonal trends. The third visualization highlights how rodent complaints peak during the summer months and dip during the winter. Warmer weather typically increases rodent activity, leading to more sightings and complaints, while colder temperatures tend to reduce rodent movement.

By adjusting the time scale and grouping the data by different factors, we can reveal new insights—such as the impact of seasonality and geographic variation—on the rodent problem in NYC.

---

2. Where Do Rodent Complaints Occur?

Understanding where rodent complaints are made is just as important as understanding when they are made. Grouping the data by location type reveals valuable insights into where New Yorkers are most likely to encounter rodent issues. The treemap below breaks down 311 calls based on the location of the sightings.

As the treemap shows, a significant 73% of rodent complaints originate from residential areas. This does not necessarily indicate that rodents are more common in residential spaces, but rather suggests a potential reporting bias. Homeowners and renters are more likely to report rodents because the presence of pests has a direct and immediate impact on their living conditions. In contrast, people may be less inclined to report rodents in public spaces, such as the subway or parks, where they do not feel personally responsible for taking action.

The next largest categories of complaints come from food-related spaces, including restaurants and grocery stores, followed by non-residential areas, such as offices and commercial buildings. Complaints from vacant spaces and construction sites also make up a notable portion of the total, pointing to the potential for rodents to thrive in these less maintained environments.

Breaking down this data further by borough reveals additional patterns:

As the bar chart shows, Brooklyn leads with the highest number of rodent complaints across all location types, particularly in residential and vacant spaces. This could indicate both a higher rodent population in Brooklyn and a greater tendency of residents to report sightings.

In Manhattan, the majority of complaints also stem from residential areas, but the borough stands out for a larger proportion of reports from non-residential and food-related spaces, reflecting the commercial and dense urban nature of the area.

Meanwhile, the Bronx shows a particularly high percentage of complaints from residential areas, reinforcing the trend that homeowners and renters are more likely to report rodent activity.

Queens and Staten Island show fewer complaints overall, but a similar pattern emerges: most reports are made in residential areas, with some activity in food-related spaces and construction sites.

This distribution highlights the need for targeted rodent control efforts, particularly in residential neighborhoods and food establishments. It also raises important questions about the management of waste and hygiene in public and commercial spaces across different boroughs.

---

3. When Do New Yorkers Report Rodent Complaints the Most?

After examining when and where rodent complaints occur across the city, I wanted to uncover more detailed insights by focusing specifically on residential areas and narrowing the scope to a recent one-year period from October 2023 to September 2024. This approach helps reveal more precise patterns that indicate how frequently residents encounter and report rodents.

To achieve this, I grouped the data by time of day and month, adjusting the time bucket to better understand when New Yorkers are most likely to report rodent activity in their homes. The heatmap below shows the density of rodent-related 311 calls across each hour and month within this focused time period.

Several patterns emerge:

• Time of Day: The majority of complaints are made between 9 AM and 3 PM, with a clear peak around 9 AM to 12 PM. This suggests that rodent sightings are often reported during daylight hours, possibly as people go about their morning routines and work commutes.
• Month: Complaints are highest during the warmer months, particularly from June through September, possibly due to increased rodent activity as food sources become more available.

This grouped data provides a clearer picture of when New Yorkers are most likely to encounter rodents and make a report. Now, let’s dive deeper by examining the same data for individual boroughs to see how these trends vary.

Manhattan

In Manhattan’s residential areas, rodent complaints peak at different times, especially during the summer months of May and July, with reports spreading from 9 AM to 9 PM. 

Brooklyn

Brooklyn, the borough with the most reported rodent sightings, shows a pattern similar to the overall city-wide trend, with complaints peaking between 9 AM and 10 PM during the warmer months of the year. 

Bronx

The Bronx has a broader seasonal spread, with rodent complaints peaking from February to October, focused mainly in the morning hours between 9 AM and 11 AM. 

---

Conclusion

What We Learned

From the analysis of NYC’s 311 rodent complaint data, several important patterns and trends emerge.

1. Steady Increase in Rodent Complaints Over Time: The overall number of complaints has grown significantly since 2010, peaking in 2023 with over 49,000 calls, nearly doubling the complaints from a decade earlier. The temporary dip in 2020 during the COVID-19 lockdown suggests that reduced human activity might have influenced both rodent behavior and reporting patterns. However, complaints spiked again as the city returned to its normal pace.
2. Borough-Specific Trends: Brooklyn stands out as the borough with the most rodent complaints, especially in residential areas and vacant spaces. Manhattan shows a larger proportion of complaints in commercial and food-related spaces, which reflects the borough’s dense urban environment. Interestingly, the Bronx has seen a decline in complaints since 2021, while Queens and Staten Island report fewer overall complaints but still follow the trend of higher activity in residential areas.
3. Seasonal Peaks and Time of Day: Rodent complaints peak during the summer months (June to September), with significantly lower activity in the colder winter months. The majority of reports are made between 9 AM and 3 PM, suggesting that residents encounter rodents during their daily routines, particularly in the morning.
4. Residential Areas Dominate Reports: Across all boroughs, 73% of complaints come from residential areas, indicating a potential reporting bias. Homeowners and renters are more likely to report rodents due to the direct impact on their living conditions, while sightings in public spaces may be underreported.

Limitations of the Data

While the 311 rodent complaint data provides valuable insights, there are a few key limitations to consider:

1. Reporting Bias: The dataset reflects where complaints are reported, not necessarily where rodents are most active. Residential areas dominate the reports, but this does not mean that rodents are only found in these locations. Public spaces, like subways and parks, may have high rodent activity but fewer reports due to a lack of personal responsibility to file a complaint.
2. Lack of Population Data: The data does not provide information on the actual rodent population. Complaints are a reflection of human sightings and reports, but without population data, we cannot accurately measure the scale of the rodent problem in each area.
3. Varying Levels of Public Awareness: The number of complaints could also be influenced by differing levels of awareness and access to 311 services across neighborhoods. Some residents may be more proactive in reporting, while others may be unaware or indifferent to the reporting process.
4. Effect of New Policies: While the city has recently implemented new rodent control measures, such as the trash containerization strategy, it is still too early to determine the full effect of these policies on rodent activity and complaint numbers. A longer-term analysis would be needed to assess whether these initiatives have made a measurable impact.

By understanding these limitations, we can better interpret the trends revealed by the data and recognize areas where further study or additional data may be necessary to fully grasp the extent of the rodent problem in New York City.

Next Steps

The next step for my analysis is to continue monitoring the impact of new policies and refine the data by zooming into ZIP code-level trends. This will help me gain a more localized understanding of rodent activity and assess how recent initiatives are affecting different neighborhoods.

Here’s how I plan to approach this:

• Track complaint trends by ZIP code to identify where rodent activity is most concentrated and where improvements are happening.
• Compare pre- and post-policy data to evaluate the effectiveness of new measures like trash containerization.
• Examine ZIP codes with consistent declines in complaints to uncover successful interventions or environmental factors.
• Incorporate additional data points like neighborhood density and socioeconomic factors to better understand the drivers of rodent activity.

By focusing on these steps, I’ll be able to refine my understanding of where rodent control efforts are most needed and where progress is being made.