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Friday, October 4, 2019

And no birds sang


Fifty-seven years ago last week – September 27, 1962 –  Rachel Carson published Silent Spring, the book that really got us thinking about what we are doing to the environment.

Silent Spring predicted more future consequences from indiscriminate use of pesticides and other ways that we are abusing our world. Those predications are coming true.

A dramatic new analysis published in the journal Science says the U.S.-Canada bird population is almost three billion birds smaller than it was 50 years ago. The analysis is based on a study by seven research institutions in Canada and the United States.

The number – 2.9 billion fewer birds - is shocking, but not totally surprising. That fits with my observations at the cottage, where songbirds once provided an abundance of  joy.

A few finches and grosbeaks, once a daily feature at our place, showed up a couple of months ago, bringing a spark of hope. But this fall there is little birdsong around our place and walks in the woods have not flushed one ruffed grouse.


Almost six decades after Silent Spring, I am witnessing Silent Autumn.

Habitat loss and pesticides are two proven causes of bird decline. There are fears now, however, that changing climate is a contributing factor.

Scientists says there is no evidence that climate change is directly killing birds. Changing climate is, however, having indirect effects.

Recent studies have reported huge declines in insect populations. Insects and birds are hugely important to each other. Many birds eat insects for food. So fewer insects to eat means more birds searching for food to stay alive.

More importantly, rising world temperatures are bringing insects, and diseases they carry, to places they have never been before. For instance, mosquitoes carrying malaria, West Nile Virus (WNV) and other diseases are populating areas beyond their historical range.

There is a ton of Americans research on the impact of mosquito-borne disease on birds. U.S. studies have detected the presence of the West Nile Virus in more than 300 species of birds, including ruffed grouse.

Little research has been done in Canada, possibly because nasty bugs and the nasty things they transmit have been limited to warmer areas south of us.

That is changing. Our temperatures are rising and bugs and viruses are moving north. Ticks carrying Lyme Disease are one example. Mosquitoes transmitting the WNV are another.

Canadian research, especially into the impact of West Nile on birds, is urgently needed,
Thankfully we are getting some, from Dr. Amanda MacDonald, a University of Guelph researcher specializing in wildlife disease.

Her study is building data on wild turkeys and ruffed grouse exposed to West Nile in Ontario and Quebec. She is encouraging turkey and grouse hunters to help by submitting blood samples from birds they have shot. The study supplies filter strips for blood collection and postage-paid envelopes for submitting the samples.

Birds can be infected with West Nile when bitten by a mosquito which has bitten and drawn blood from an infected bird or animal.

Not all birds exposed to the virus become ill, or die. However, it does seem to hit hardest the corvid family of birds, of which crows and jays are members.

American research indicates that West Nile is reducing ruffed grouse populations. MacDonald’s study will provide information about levels and locations of exposure and could be a start to determining whether West Nile is a factor in shrinking grouse populations.

It also will be important for wild turkeys. Governments and private organizations spent much time and money on reviving wild turkey populations in Ontario. Any threat to that revival needs quick and thorough research.

We must learn everything about what is killing the birds so we can do more to prevent the losses. Not just because they are lovely to look at and wonderful to listen to.

West Nile, Lyme and other insect-borne diseases are becoming more common in our world. So far this year the U.S. Centers for Disease Control has reported well over 300 human cases of WNV, with 45 states and the District of Columbia reporting exposure in mosquitoes, birds or humans.

Silent Spring warned us 57 years ago. Now things that can hurt us are moving our way and we need to be better informed, better prepared.

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