Volunteers fanned out across Vancouver overnight, visiting shelters and scouring alleys, parks and any other areas where the homeless might take refuge.

Participants -- including Mayor Gregor Robertson -- are taking part in Vancouver's third annual count of homeless residents.

The tally began at 6 p.m. last night and wraps up at six tonight -- with the numbers used to track Vancouver's progress toward ending street homelessness by 2015.

Robertson holds a news conference at 8 a.m. this morning, following his shift with the volunteer enumerators.