In this episode of BirdNoir, the Private Eye sees some suspicious activity: a House Sparrow tries to steal a nestbox from Tree Swallows, but then flees the scene in terror. He stakes out the nestbox to see what the Tree Swallows are doing to keep intruders away.More info and transcript at BirdNote.org. Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.