Information transfer and utilisation is ubiquitous in nature. Statistical decision theory uses Bayes theorem to effectively model how animal’s process information gained from their environment. Information is defined as valuable if the gain in knowledge changes the receiver’s state significantly as a consequence where value is measured in terms of fitness consequences. Previously it has been shown that the reproductive value of information can never be negative because it reduces an animal’s uncertainty about the state of the world (McNamara and Dall 2010). A new expression for the value of information is given and applied to the context of parental care decisions in a monogamous species.

The case modelled concerns a species where incubation is shared by both parents. The incubating mate must make a decision of how long to wait at the nest for their partner to return from foraging. The population is comprised of two types; some individuals will return to the nest whereas others will abandon it. The incubating mate’s optimal wait time before abandoning the nest themselves given an initial estimate from the population of the likelihood their partner is of the type to return, p, is found by maximising the incubating mates payoff function. It is shown that as p increases, the optimal waiting time is longer. Differentiating the optimal payoff function with respect to p allows us to quantify the value of information. Gaining knowledge allows refinement of the initial estimate of p altering the incubating mates waiting time, thereby increasing the expected payoff. Monogamy is the prevailing mating system in birds and much is to be understood of the functions and mechanisms behind these long term affiliations. The value of knowing your partner may explain why some species form long term relationships.