Connecting people with nature in Ontario's Mississippi Valley

Wild Fluctuations of Bird Numbers at the Almonte Lagoon – Fact or Fake News?

This year again, the Mississippi Valley Field Naturalists, held four bird-watching events at the Almonte Lagoon. The Fall Open Houses, as we call them, took place on consecutive Wednesdays in September at the brand-new Mike McPhail Bird Viewing Shelter. The total number of visitors during the four events topped one hundred.

Enthusiastic birders at the Mike McPhail Bird Viewing Shelter

Before the first event on Sept 5th, we celebrated the official opening of the shelter. After speeches and ribbon cutting, visitors filed into the structure where our volunteers showed many species of birds to anyone interested in looking through one of the available scopes. And so it went for the first two events: people in the shelter, ducks and geese on the water, birds in the sky, and hot weather for all.

To some of the observers, the hot weather of the first two weeks seemed to hinder bird movements. Ducks in particular, did not fly to and fro as much as expected, and numbers appeared to be down.

The third week saw cooler temperatures and the arrival of a large flock of Canada Geese. Now the lagoon was covered with geese and ducks. Thoughts of fewer birds dissipated in the breeze.

During one of the later events, a few conversations turned to climate change and how it could possibly cause wild fluctuations in bird numbers. Were those conversations based on facts or on subjective observations? In the past, we had to rely on personal experience to form a judgment on this, but not anymore.

For the last three years, volunteers from our birding committee have recorded our events’ data into eBird, an online citizen science tool launched in 2002 by Cornell Lab of Ornithology at Cornell University. eBird keeps our data in a central database, available to us at the click of a mouse. Now, we can find out what is really going on with our bird numbers.

Take a look at the following charts. The average number of birds spotted at the Almonte Lagoon during our fall events decreased in 2017 only to bounce back higher this year. On the other hand, the number of species increased in 2017, but decreased this year. So, we end up with a quandary: more birds counted in the years when fewer species are present.

Do those charts show that our bird numbers fluctuate because of climate change? We do not have enough local data to properly answer that question. Some of us wish we did, but we don’t – not yet anyway. Many factors may have skewed this year’s high bird count. For instance, had the large flock of Canada Geese arrived one week later, our average count would be lower. Also, the experience and accuracy of our birdwatchers may have changed over the three-year period. More importantly, the time frame and the sample size of our data are too small.

But what about the hot weather of this year’s first two weeks? Well, some people would say it was just a normal fluctuation. Hum… So many factors to consider…

In any case, our data gathering is a good start. Our checklists now form part of eBird’s database, a database that includes more than twenty million checklists – a huge sample size. It includes historical sightings going back to the days of the passenger pigeon.

Scientists across the globe use this windfall of data to study anything and everything that has to do with birds, including the effects of climate change on bird populations.

Their findings? Yes, climate change has an enormous effect on bird populations. Some species fare better, others worse. Migration patterns change. Ranges expand or contract depending on how well species adapt to change, and according to Nature Canada (How is climate change affecting birds?), extinction risks are on the rise.

But hey, we should remain neutral and not speak about climate change. After all, it’s fake news, right?

Enough said for now. We will revisit the issue next April, after the Spring Morning Walks, yet another yearly MVFN series of bird-watching events.

Until then, hold on to your binoculars.

Photo, charts and report by Michel Gauthier, MVFN

Click here for bird species and numbers at 2016, 2017, 2018 Almonte Fall Open Houses – an xlsx document

Link to current e-bird data for this location at https://ebird.org/canada/printableList?regionCode=L2327732&yr=all&m