Three of the falcon statuettes made for the production still exist and are conservatively valued at over $1 million each. This makes them some of the most valuable film props ever made; indeed, each is now worth more than three times what the film cost to make.
Eight Maltese Falcons were used for the movie - two lead and six plaster ones. The lead falcons weighed about 50 pounds each, and Lee Patrick accidentally dropped one on Humphrey Bogart's foot during shooting. It is on display in the movie museum at Warner Bros. studios, and its tail feathers are visibly dented from when it was dropped.
Humphrey Bogart had to supply his own wardrobe. This was common practice at Warner Brothers as a way for the studio to save some money.
At 357 pounds, 60-year-old British newcomer Sydney Greenstreet was so large that the studio had to specially manufacture his entire wardrobe for the role of Kasper Gutman. The chair in which Greenstreet sits while talking with Sam Spade (Humphrey Bogart) in the hotel room was also specially made for him; the chairs the prop department was going to use weren't wide enough to accommodate Greenstreet's girth nor strong enough to support his weight.
It was producer Henry Blanke who gave John Huston what he recalled as the single greatest piece of advice he would ever receive as a director: "Shoot each scene as if it was the most important scene in the film."