Research Update from Harold Eyster
It’s now been more than a year since I jotted down the last bird observation and completed my year of bird surveys in Greater Vancouver, including over 500 point counts and 300 transect surveys. I learned so much about the city and its birdlife by visiting of streets every week and seeing how the local birdlife changed.
Images captured by Harold Eyster from the same spot along one of his transects throughout the year in Vancouver.
In the last year, thanks to funding from Environment and Climate Change Canada and the Gund Institute for Environment at the University of Vermont, I’ve been diving into these data to understand how Vancouver’s birdlife has changed over the last several decades and how it varies across the Metro area.
Canada Goose, Sora and Virginia Rail, observed and painted by Harold during bird surveys in Richmond, BC.
Now, we have preliminary answers to these questions, thanks in large part to Morgan Fletcher’s expert work in transcribing hundreds of hand-written datasheets. Over the coming months, we will be building spatial models to get clearer answers to these questions, but these preliminary results offer an enticing peak at what those models might reveal.
Preliminary Results
Where are there more birds?
Preliminary results show that there seem to be more species in the more forested regions of the city, including Pacific Spirit Regional Park, Stanley Park, and Burnaby Mountain.
Next, we’ll be combining these data with the data that the Vancouver Cat Count collected to understand where birds are most at risk from cats.
Map of bird species abundance in survey areas of Vancouver. Prepared by Harold Eyster.
Have birds declined since the late 1990s?
In the late ‘90s, Stephanie Melles conducted these same bird surveys. How has bird abundance changed since then?
Some birds have likely declined by more than 50%, including Violet-green Swallow, Barn Swallow, American Robin, Glaucous-winged Gull, European Starlings, and others. Stephanie saw more than twice as many of these birds back in the 90s than I did. Have you noticed fewer of these species, too?
Tree Swallows and Glaucous-winged Gulls seem to have declined over the last 20 years.
But other birds have likely increased, including Pacific-slope Flycatchers, Black-capped Chickadee, Chestnut-backed Chickadee, Anna’s Hummingbird, White-crowned Sparrow, and Northern Flicker. Have you noticed more of these species, too?
Black-capped Chickadees seem to have increased over the last 20 years.
Research assistants Morgan Fletcher and Addie Robinson are hard at work transcribing the datasheets for the surveys that replicate data from the 1960 and 1970s, so we should hopefully have those results soon, and be able to understand how bird numbers have changed over the last 50 years.
In the meantime, I’m gathering old aerial photos and building machine-learning models to understand how Metro Vancouver’s landscape has changed in the preceding decades and then using those changes to explain changes in bird abundance. Stay tuned!
Visit our Cats and Birds Research page to learn more about this research project. Find out how to keep pets and wildlife safe on our Cats and Birds pages.
