The main drawing card of Drawbridge was hunting and fishing. Particularly hunting, and specifically ducks. Lots of ducks. Many of the structures on Drawbridge were designated as duck clubs.
"In the fall, the island and
surrounding marshes were the stopping-off place for thousands
of waterfowl: mallards, teal, widgeon and ruddy ducks, to mention
a few. The unpolluted sloughs afforded a home for crabs, clams,
oysters, shrimp, mussels, striped bass and salmon."
Before it was declared illegal in 1910, a particularly dramatic form of hunting occurred called "Market Hunting." A cannon was stuffed to the brim with chains, buckshot, and nails. When a nice thick swarm of ducks flew over, the cannon was fired. Legend has it that five hundred to one thousand ducks would fall out of the sky after one mighty blast. The hunters would take their haul to San Francisco and fetch a pretty penny. I find the body count hard to believe - it would be interesting to repeat the experiment for verification. It must have been like manna from heaven seeing all those ducks fall. By the 1920's, hunting was strictly recreational.
Myriad species of birds exist in the South Bay, some dangerous to humans. Swallows, Avocets, and Sand Pipers entertain themselves by dive-bombing human intruders. Drawbridge folk would protect themselves by holding newspapers over their heads.