Migration Monitoring

PEPtBO began monitoring bird populations in 1995, and 2025 will mark 30 years of this work. Our goal is to serve as a vital resource on birds breeding and migrating through southeastern Ontario. Situated at the intersection of the Atlantic and Mississippi flyways, PEPtBO plays a key role in monitoring bird populations and identifying threats that could have widespread effects across eastern North America and beyond.

Monitoring birds during migration allows us to collect data on birds that do not breed locally.

The highest concentration of birds in our area is during peak migration in spring and fall. In spring, favorable winds are those coming from the south which helps birds migrate north to their breeding grounds. In the fall we observe the opposite effect where north winds encourage birds to migrate south towards their wintering grounds.  

Each season, we band birds to track populations and demographics, combining this data with our census observations to create a comprehensive view of bird population health and movements. Census and daily observations allow us to monitor species we do not catch, and conversely, banding data detects species that are difficult to see or those that infrequently vocalize. Similar to our banding protocol, census is conducted in a standardized manner every day during spring and fall migration and entails counting all birds seen and heard by a single observer in a particular time-frame on a pre-set route. The totals are submitted yearly to the Canadian Migration Monitoring Network (CMMN) to assess population trends. The CMMN is a network of 25 Canadian stations that contribute data for analysis. Tracking bird trends helps inform overall management and conservation efforts. In addition to our research partners, we also submit our data to a database managed by the Bird Banding Office, part of Environment and Climate Change Canada (ECCC) under Canadian Wildlife Services, which oversees banding activities across Canada. This branch of the government is linked to the U.S. Geological Survey, creating a centralized database for all North American bird banding data. When a bird is recovered through banding operations or found (e.g., window strike, cat predation, injury) we can trace its origin and gather insights on its movements.

Each year we band anywhere from 10,000 to 15,000 birds.

More birds are captured in the fall than the spring because fall is a longer season and the time when the young birds are attempting their first migration. This increases the number of birds in the area. We also recapture several thousand birds each year. This includes all recaptures, but most will be same-season recaptures which are essentially birds banded by us that are caught again in the subsequent days (or weeks) after initial banding. The recapture of these birds provides data about the length of time birds are using local stopover habitat. We also sometimes recapture birds banded elsewhere; these are rare events and we are always excited when it happens. For example, we recaptured a Field Sparrow in 2023 that was originally banded the previous year as a juvenile bird in Texas!