Few birds visit our backyard this time of year. But, it is December and we have no feeder. It does, however, offer a sense of what the world would be like without birds.
Having lived in the same place for 35 years, I’ve noticed a change in the mix of bird species and numbers. I’m sure there are many reasons for these changes. Cat predation, for example, is estimated to kill over 280 million birds in Canada annually, and in those United States, the numbers range from 1.3 to 3.7 billion. I’m sure habitat destruction plays a role as well.
Combined, cat predation and collisions with windows, vehicles, and transmission lines caused > 95% of all mortality … We also found that mortality is not evenly spread across the country; the largest mortality sources are coincident with human population distribution, while industrial sources are concentrated in southern Ontario, Alberta, and southwestern British Columbia. Many species are therefore likely to be vulnerable to cumulative effects of multiple human-related impacts.
A study by the Audubon Society, Survival by Degrees, adds climate change to the mix of impacts on the North American population.
Most noticeable for me, in our place, is the change in the mix of bird species. When we moved here, the most common bird was the Robin. We rarely saw a Cardinal. Now, the mix is completely reversed; dominated by Cardinals, with only a few Robins.
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