Dozens of bird species are suffering an “alarming” decline in their populations due to the destruction of their habitats and the repercussions of the climate crisis, warns a new scientific report published Tuesday by the federal government.
The data contained in the document The state of Canada’s bird populations give an idea of the threats weighing on the diversity of avian fauna that can be observed in the country.
No less than 168 species, or 36% of bird species in Canada, have suffered declines in recent decades. A finding described as “alarming” by the experts who signed this report produced by Birds Canada and Environment and Climate Change Canada.
“A crisis rages on the Prairies. The number of grassland birds has decreased by 67% since 1970, and there is no sign that the situation will stabilize,” underlines the document, pointing to “the destruction and degradation of natural grasslands”. Among shorebirds, birds which frequent wetlands and marine environments in particular, “the marked decline in populations continues”: 42% since 1970.
Aerial insectivores, which feed on insects caught in flight, have lost 43% of their populations. “Recently, the trend has stabilized. Although this is a sign of hope, populations today are much lower than they were before. Declining insect populations are likely to blame for this loss, and reversing this trend will help save endangered birds, such as the bank swallow and chimney swift, the experts explain in the report.
Long-distance migrants, who spend the winter in tropical regions, have lost 29% of their numbers. “Habitat loss threatens them at all stages of their annual cycle and their long journeys expose them to additional risks. International cooperation is essential to the conservation of species such as the barred warbler and the wood thrush, which are found particularly in Quebec.
In addition to the 168 species that have definitely suffered a decline, the report lists 98 species that “experienced little change in numbers,” and 54 for which “data are insufficient to determine a trend.”
In contrast, 143 species experienced an increase, out of the 463 that were evaluated by experts. This is particularly the case for raptors and waterfowl, which includes ducks, geese and geese.
Several threats
In addition to the destruction of natural environments, such as forests, climate change “poses a significant and growing threat to Canada’s birds,” notes the report, which mentions the increase in extreme weather episodes that put birds at risk: storms, floods. , droughts and forest fires.
Furthermore, outdoor domestic cats and stray cats kill more than 100 million birds each year in Canada, which also represents a direct threat to several species.
And according to available estimates, and cited in the report, “collisions with windows kill on average more than 25 million birds in Canada each year, especially when many species pass through urban and suburban areas during migrations.” “Millions” of birds are also killed each year in collisions with vehicles and power lines.
Contaminants and waste further affect birds in all environments. Pesticides and other contaminants from agricultural and industrial sources threaten both birds and their habitats. In addition, the ingestion of plastics is a cause of mortality, particularly of seabirds, scientists have been observing for several years.