Ontario researchers link declining wood thrush numbers to housing and other development | 24CA News

Population numbers for a migratory songbird that calls Ontario’s Waterloo area residence have been on a steep decline over the previous 20 years, and housing and different developments constructed round their habitat could have one thing to do with it.

Researchers with the University of Guelph (U of G) checked out wooden thrush chook abundance and nest success from 70 woodlot websites throughout the area from 20 years in the past, and in contrast the findings with knowledge they lately collected on these similar websites.

“The first thing we found was that there were no wood thrush in a lot of the places they use to be in,” mentioned Karl Heidi, one of many lead researchers who now works for Ontario Breeding Bird Atlas.

According to the Ontario authorities, the wooden thrush lives in mature deciduous and blended (conifer-deciduous) forests. While the birds want massive forests, they’re going to additionally use smaller stands of bushes and construct nests in residing saplings, bushes or shrubs.

Heidi mentioned that for his or her analysis, they solely discovered the chook in a few third of the 70 woodlot websites.

“It’s telling us that there’s been a strong decline in the population, which is what we have seen across the range of the bird,” he mentioned. 

“These birds also live in the United States across the Appalachians and other parts of the east, and there’s been a noticeable decline in those areas as well over the last 30 or 40 years.”

Their analysis discovered the drop in wooden thrush numbers was strongest in websites that had growth and housing constructed round them.

“We recorded a 79 per cent decline of wood thrush in forest fragments that experienced development around that fragment,” mentioned Ryan Norris, an affiliate professor within the division of integrative biology at U of G who was additionally a part of the research.

“If you put houses around a forest fragment, you have a good chance of losing wood thrush in the forest fragment.” 

Wood thrush are delicate to alter

Heidi mentioned wooden thrush, in contrast to robins or cardinals, are delicate to any form of change or disruption round their habitat. 

“These migratory birds just aren’t adapting as well to change, and you notice it when you’re in the field that they are more skittish and wary of people than would be a robin or chickadees.”

He additionally pointed to rising modifications to the wooden thrush’s wintering grounds in Central America and different points that come up throughout migration, resembling window collision and concrete gentle air pollution, as potential contributors to their decline.

The Ontario Ministry of the Environment, Conservation and Parks mentioned the wooden thrush is a species of “special concern,” which implies it isn’t endangered or threatened however might be below a “combination of biological characteristics and identified threats.”

The ministry’s web site lists lack of forest habitat from city, suburban and cottage growth as one of many main threats confronted by the chook.

Norris and Heidi mentioned the decline in inhabitants is regarding they usually fear in regards to the wooden thrush’s future.

“We’re losing the abundance of the bird, but the birds that are remaining are tending to do OK in terms of nest success, but that’s not enough to compensate the loss of the size of the population,” Norris mentioned. “It is at risk, no doubt.”

Heidi feels the identical.

“It’s probably been tens of thousands of years since it first evolved in this region, so to see this kind of a decline over what’s really a blink of an eye in its history is really alarming.”

Population decline may have wider implications

Losing the wooden thrush in all probability would not influence day-to-day life, Norris mentioned, however we must always care as a result of what’s occurring to this chook is probably going occurring to others.

He mentioned birds play an important half in the ecosystem and dropping massive numbers may have wider implications.

“We can’t always predict what will happen because it’s such a complex machine, the ecosystem, but migratory birds are a big cog in that ecosystem.”

Now that the research has wrapped up, Heidi will head to the Sudbury space in northern Ontario over the summer season to review wooden thrush there. 

This research is barely the start of a bigger undertaking trying into chook inhabitants modifications as an entire throughout Waterloo area within the final 20 years.

“Being able to see what the changes were in this region after 20 years of development is really crucial because we had so much historical data, and now we have the current status of things which is very useful,” he mentioned.