Chimney Swift Monitoring 2024

New monitors are always welcome! Experienced monitors will welcome you and help you master the monitoring, reporting, and safety procedures.

Nature London’s Chimney Swift Monitoring Program is coordinated by Glenn Berry, Susan Berry, and a committee of eight other monitors. The main point of contact is

There is more information about swifts and monitoring at Chimney Swift Resources 2023. Amazing Facts about Chimney Swifts is one of the many articles on that page.

Chimney Swifts

Chimney Swifts are small, dark birds that are in London from late April to early October. Their chittering sounds (heard on the above video) alert us to their presence. They fly high, snatching insects from the air. Swifts spend almost all of their time airborne as their feet aren’t designed for perching and are better suited to clinging to rough vertical surfaces. For that reason, they build twig-and-saliva nests usually deep inside old chimneys, one nest per shaft.

Finding Swifts

As soon as you hear them, look up. You will see them zig-zag as they hunt. When gliding, they look like fat cigars with boomerang-shaped wings. Once you learn their sound, you will notice them in most areas with old chimneys in southern Ontario.

The Importance of Monitoring

Nature London shares its data with the provincial database maintained by Ontario SwiftWatch. Our information helps inform conservation decisions and contributes to the knowledge of swift population changes.

Monitoring Timetable

In 2024, we plan to monitor on Tuesdays.  We will also monitor on the four non-Tuesdays of the National Chimney Swift Roost Monitoring Program of Environment and Climate Change Canada. Additional dates may be added in August and September to identify large roosts if release sites are needed by wildlife rehabilitators who specialize in raising orphaned swifts.

  • Tuesday, May 7
  • Wednesday, May 22
  • Sunday, May 26
  • Thursday, May 30 
  • Monday, June 3
  • Tuesday, June 18
  • Tuesday, July 9
  • Tuesday, July 30
  • Tuesday, August 13
  • Tuesday, August 27
  • Tuesday, September 10
  • Tuesday, September 24
  • Tuesday, October 8


Glenn prepares and circulates assignments for each night of monitoring. For the orientation of new volunteers, he matches new monitors with experienced monitors. He makes every effort to accommodate preferred monitoring partners, preferred chimney locations, and personal schedules (including last-minute changes).

Monitoring Procedures

On a typical night, you spend a pleasant hour near sunset, making observations and contributing to citizen science. The goal is for everyone to stay safe and healthy.

Before a night of monitoring, print sufficient copies of the field data recording form. Also, read the parking tips and recommended monitoring positions for your assigned location. Email any corrections or additional information that may be of use to future monitoring teams to We maintain the form and the details for each chimney location in a password-protected area of the Nature London website.

Start monitoring 30 minutes before sunset until 30 minutes after (or until it is too dark). Sunset time is included with each monitoring assignment.

If it is cold (<13º), cloudy or rainy, you may want to start monitoring 45-60 minutes before sunset. Alternatively, you may choose to monitor on a subsequent night when conditions are better and your partner is available. For most locations, you can monitor from inside your car, even in steady rain.

Always bring the following:

  • Printed field data recording form for each chimney to be monitored.
  • Pencils, clipboard, timepiece, swift business cards.

Consider bringing the following:

  • Lawn chair, seasonal clothing, water, insect repellent, phone, buddy.
  • Binoculars are useful for identifying other birds and animals. Note that binoculars should not be used when observing at residential buildings. 

Fill in preliminary data on the form: date, location, observer name(s), sunset time, weather codes, start time, and whether you are making a video recording.

For locations with two chimneys, complete a separate form for each chimney, deciding in advance which monitor is responsible for monitoring and recording at each chimney.

To the nearest minute, record times and numbers of swifts entering and exiting a chimney. For big numbers, record estimates and approximate time intervals.

To complete the form, record your stop time, times of first and last entries by swifts, plus any other notes of interest; for example, swift behaviours. 

Monitoring Tips

One monitor should be watching the top of the chimney at all times.

Record the times and numbers of all swifts entering or leaving the chimney.

Try to avoid counting near misses.

If many swifts enter at about the same time, switch to counting/estimating by 5s or 10s.

Record any interesting swift behaviour, possible predators, and other observations.

To estimate the number of swifts inside the chimney for the night, subtract exits from entries.

If at any time during the evening, you find your number of exits exceeds your number of entries, there were swifts in the chimney before you arrived or you missed some entries.

Reporting Observations

Use the online data entry form. The fields of the online form are in the same order as the fields of the printable form. Each chimney monitored must be reported separately.

Submit a report even when there are no swifts. Such reports are valuable.


The one who submits a report online receives a confirmation email containing the information submitted. We publish a summary of monitoring results for each monitoring date.

Throughout the monitoring season, we will be sharing swift news and swift videos. When appropriate, we will share words of wisdom from experienced monitors.

Personal Safety Advice

Here are some suggestions for your comfort and safety.

  • Always monitor with a partner.
  • Carry a phone.
  • Remain aware of your surroundings.
  • Place lawn chairs in an area of high visibility or monitor from a vehicle.
  • Respect private property and pedestrian traffic.
  • If you feel unsafe at any time, leave immediately.
  • Carry swift cards to give to curious passersby, but don’t be distracted. The QR code on the card links to this webpage.

By participating, you assume full responsibility for all aspects of your personal health and safety during a monitoring session and while travelling to and from the site. This includes compliance with all provincial regulations and local health-unit directives, if any, that might be in effect. It is also your responsibility to ensure the others you invite to join you are aware of these conditions of participation.