They'll be taking part in a nationwide project sponsored by San Francisco State to gauge the health of bee populations in major cities.
One of those bee counters is Susan Karasoff. In San Francisco's North Beach neighborhood, Karasoff nurtures a garden that is a pocket of seemingly thriving beauty, bursting with color.
For Karasoff, the living bouquet of flowers and edible herbs is made even more special because of its location in the middle of a city, surrounded by concrete and high rises.
But there is also a problem in the garden: the blossoms bloom a little less every year. There's a reason.
The garden, in the peak of growing season, has become practically devoid of bees. Karasoff has tried to attract them with a bee house, but there are still no tenants.
Nobody knows more about that than Dr. Gretchen LeBuhn at San Francisco State. She has been monitoring bees in American and Canadian cities since 2008, using 100,000 citizen scientists like Karasoff to count them.
Numbers don't lie. "And now I think we have fewer bees, but it may have been we've had fewer bees for a longer period of time and no one noticed," said LeBuhn.
Put simply, it appears to be a matter of diminishing habitat. But in major cities, bee-friendly places do exist.
Last week, in San Francisco's Richmond District, bee counter Shelly Esson encountered a swarm of bees moving from yard to yard in a neighborhood filled with green, natural growth.
In the Richmond District, "they have more park land, more areas with larger gardens and less concrete," LeBuhn said.
In the context of Dr. LeBuhn's work, it's good news mixed with bad. The bees are going, but they're not gone. And given a proper welcome mat, they're happy to come back, even to cities.
