Darwinian signaling update

Are the starlings who sing while being chased by hawks showing off for their girlfriends? Or maybe warning their families?

Saturday, I posed a puzzle about predator-prey signaling in a Darwinian framework, and asked for proposed solutions, and I’ve had a gratifyingly large and intelligent group of responses. So far, no one who knows the particulars has written in, but my readers offered two classes of suggestions; either one is a plausible story.

1. The signaling behavior may itself be a mate attractor and thus selected for that reason, or it may be part of a larger pattern (say, singing while flying fast) designed to attract mates. Eventually, as the proportion of starlings exhibiting that behavior rose, it acquired a second advantage as the merlins learned not to give chase.

2. The signaling behavior might have originated as a warning to conspecifics. Such behavior can be selected for if those who benefit tend to be more closely related than average to the individual exhibiting it. Again, in this story the predator signaling comes in later.

Note that both of those possibilities have testable implications.

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: Markarkleiman-at-gmail.com