For the first time the city of Montreal is taking a census of its homeless population.

The idea is modelled after similar counts already done in other cities, and so for three nights this week "I count Montreal" will try to list as many people as possible in the city with no fixed address in the hopes of better serving their needs.

More than 1,000 volunteers gathered at the downtown YMCA Tuesday night to begin the census.

Among them were people who already volunteer for those in need.

"At the NDG food depot we try to keep people from the streets, so this is one small thing I could do to help out," said Bonnie Suttar as she began her night of counting.

Other volunteers, such as Alain LeBlanc, were men who had been homeless.

"I was on the street at 14 years old so back then there was almost no resources, almost none," he said.

This week's count was organized by the YMCA with the Douglas Research Institute and several downtown shelters, and funded by the city of Montreal.

"If you want to be accurate in the way we create some policies, we need some strong data," said Mayor Denis Coderre.

The response for volunteers was overwhelming.

"In six days we had 600 and in ten days we essentially closed down the inscriptions because we couldn't handle anymore," said James McGregor.

Tuesday evening began with an information session for the volunteers, and then crews went into the night.

Nancy Marelli and her team worked in the area around Victoria Square, where they asked everyone they met if they had a place to stay that night.

"To have evidence-based decision making you have to have the evidence. So this is very much about collecting that evidence," said Marelli.

Estimates for the number of homeless people in Montreal range from 12 to 30,000, so the census-takers hope they will have a much better picture once the week is finished and the data is analyzed.