Researchers need help to determine which birds are most at risk from climate change. Here's what you can do

The early bird gets the worm, the old saying goes. That's even truer today due to climate change, as many birds return to Ontario too late to catch their favourite meals.

While trees leaf out and insects emerge in response to temperature, birds start their migration from down south mainly in response to the length of the day. Although climate change means spring temperatures tend to arrive earlier, the days don't get longer any faster. 

This creates a mismatch between when insects or other food sources are most available and when the birds are around to eat them. 

"That balance of when insects are available for birds and for their chicks gets thrown off," said Jonathan Chu, a PhD student at Ontario's University of Guelph who has researched bird migration. 

Now scientists are racing to determine which species will be able to adapt and which will need support — and they need your help to do it. 

A widely reported paper published in the journal Science in 2020 estimated North America has lost over three billion birds since 1970 — almost 30 per cent of all individuals. 

The causes are many — habitat loss, declines in insect populations due to pesticides, outdoor cats, window collisions — but climate change is a contributor, in part by altering the timing of life cycle cues of different species. 

One of the biggest problems is that it varies so much between species, explained Jeff Skevington, an entomologist at Carleton University in Ottawa and president of the Ontario Field Ornithologists. 

While some birds arrive earlier and struggle due to unpredictable weather, others migrate at their usual time only to find there isn't enough food for them, he said. 

Chu led research out of the University of Toronto that backs this up. Using community science data from eBird, a platform that allows anyone to submit their bird sightings, they found that while some species have been arriving earlier, others are coming at the same time they always have. 

Community science data has exploded in popularity in recent years, both in terms of people collecting it and scientific papers analyzing it. Chu emphasized how important it was to his research and the scientific community.

"Millions of people contributed [and] it's funny to think that even some of my observations are in there," he said. "You never know what your observations will be part of, and they can be part of something really great."

Unfortunately, there is little conservationists can do to eliminate the effects of climate on bird migrations. 

Instead, their goal is to identify particularly vulnerable species and reduce other threats to them to build resilience in their populations, buying them the time they need to adapt.