Climate Change

Earlier springs lead to changes in timing of bird migration and nesting

The trend to earlier, warmer springs appears to be leading to earlier arrival at prairie nesting grounds for some waterfowl and earlier hatching for some seabirds.

Canada geese arrival dates, Delta Marsh

1939 to 2001
Graph: Canada geese arrival dates, Delta Marsh. Click for graphic description (new window). Photo: Geese © iStock.com/scol22.
Source: adapted from Murphy-Klassen et al., 20056

Timing of annual arrival at Delta Marsh, along the shore of Lake Manitoba, was strongly related to the average March temperature for about half of the 96 migratory bird species studied, including Canada geese. Spring arrival dates of most of these species shifted earlier at rates of 0.6 to 2.6 days for each 1°C rise in average March temperature.6

Hatching dates for tufted puffins, Triangle Island

1975 to 2002
Graph: hatching dates for tufted puffins, Triangle Island. Click for graphic description (new window). Photo: Tufted puffin © Kyle Morrison.
Source: adapted from Gjerdrum et al., 20037 and Gaston et al., 20098

Tufted puffins, rhinoceros auklets, and Cassin’s auklets at Triangle Island off the B.C. coast have shifted to an earlier breeding season in the past 30 years. The populations of these burrow-nesting seabirds declined from 1984 to 2004, likely due to changes in ocean conditions. The declines may be partly caused by a mismatch between timing of nest hatching and peak food availability, as has been confirmed for Cassin’s auklets.8

Moving north

There are many observations throughout the country of shifts in species ranges, generally northward. Many of these shifts are likely related to climate change. Some examples include:

  • The northern limit of the breeding range of landbirds that breed in southern Canada moved northward by an average of 2.4 km per year from 1964 to 2002 – for example, Swainson’s thrush has extended its range 141 km northward over this period.9
  • Declining sea ice in Arctic straits has led to killer whales expanding their range into Hudson Bay where they are now sighted every summer.10
  • Northward range shifts have been noted since the 1960s in the Northwest Territories for whitetailed deer, coyote, wood bison, cougar, magpies, and the winter tick parasite.11, 12
  • White-tailed deer have been expanding northward from B.C. to Yukon since 1974 and now range as far north as central Yukon.13 They have also been observed to be expanding northward in Saskatchewan, Quebec, and Ontario.14, 15
  • The Inuvialuit of Banks Island in the Arctic have noted new species of beetles and sand flies. Robins and barn swallows are also new to the region.16
  • Northward expansion of racoons into the Prairies during the 20th century may be linked to longer growing seasons along with increased agricultural production.17