Ostrich instruction?

This is a new one on me. From a Seventh Circuit opinion yesterday, United States v. Jaffe:

An ostrich instruction is appropriate when a defendant “claims a lack of guilty knowledge and there are facts and evidence that support an inference of deliberate ignorance.” United States v. Craig, 178 F.3d 891, 896 (7th Cir. 1999). At trial, FBI Special Agent Bruce Burr testified that Jaffe said he knew the transaction was fraudulent at a certain point and that he (Jaffe) said he “agreed that he had ‘stuck his head in the sand.’” Apart from a trial involving an actual ostrich, it’s hard to imagine a case where an ostrich instruction is more appropriate than one, as here, where the defendant acknowledges “sticking his head in the sand.”