Residents of a northwest Winnipeg neighbourhood continue to wonder what caused a die off of birds at an area retention pond this summer.

The pond, located at the corner at Keewatin Street and Adsum Drive, saw sick and dying birds covering its shores, prompting the province and City of Winnipeg to submit samples for testing. 

CTV News collected its own water samples, which were then processed at ALS Environment labs. 

Those results were brought to research scientist Scott Higgins, International Institute for Sustainable Development, who has a long history of working with algae. 

Higgins explained that a kind of algae found within the retention pond could produce certain toxins, and looking for high levels of those toxins was the first step in seeking answers. 

The results from ALS Environmental included a test of one of those toxins called microcystin. 

“They’ve analyzed for one toxin here called microcystin and it’s really low,” said Higgins. 

“It doesn’t appear that that toxin is likely to be responsible for these birth deaths.” 

Higgins also said the bird deaths could be caused by anatoxins or avian botulism, but stressed that testing for avian botulism was far from a straightforward lab procedure. 

“They expose water samples that potentially contain this to mice, and then look at the mice mortality,” said Higgins. 

Looking at the results, Higgins said there was no “smoking gun” but said reducing algae blooms could potentially reduce bird deaths in a retention pond. 

Higgins explained that algae blooms often occur because of excessive nutrients, and said one step for residents would be to limit use of products like lawn fertilizer, which can then run off into retention ponds and stimulate algae growth. 

Bird deaths in retention ponds are widespread according to Higgins, and usually reported mid-July through mid-September due to conditions created by weather. 

“They’re actually really common, just typically at low levels,” said Higgins. 

“All of a sudden people get very concerned and rightfully so.” 

The City of Winnipeg and Government of Manitoba said there was no update or test results as of Wednesday afternoon. 

Sustainable Development Manitoba has previously said blue green algae or botulism could be causing the bird deaths.