Background information

General nesting periods of birds in Canada

The nesting periods published on the Status of Birds in Canada website are based on the work of Rousseu and Drolet (2017). These periods cover most of the nesting season of each species but do not take into account the nest-building period prior to the laying of the first egg, or the period of dependence of young outside the nest. These nesting periods were estimated using predictive models based primarily on mean annual temperature and using about 200,000 nest records contained in the Project NestWatch database of Bird Studies Canada.

It is possible that nesting periods for certain birds at some locations may be different from the estimated general nesting period due to micro-climatic conditions in specific areas (e.g., due to significant variation in altitude, especially in British Columbia), the natural variability of nesting events, expressed between individuals and years, and also due to the quality of the data and the constraints associated with the modeling method used.

The estimates of the nesting periods are for general information only and do not constitute official advice regarding the legal consequences of any particular activity. It is the responsibility of each individual to assess the risk of their activities and to develop appropriate avoidance and mitigation measures (see Environment and Climate Change Canada's Avoiding harm migratory birds).

For more information on birds' nesting seasons in Canada, see the General nesting periods of migratory birds in Canada.

Use the Nesting Calendar Query tool to create customized nesting calendars for species and areas of interest.


Rousseu, F. and B. Drolet. 2017. The nesting phenology of birds in Canada. Canadian Wildlife Service, Technical Report Series No. 533, Environment and Climate Change Canada, Québec Region, Québec, Canada xxii + 314 p.