Singing on the nest is a widespread behavior in incubating Northern Mockingbirds and increases probability of nest predation

In this study, we documented for the first time singing on the nest (SOTN)
in 74% of 65 Northern Mockingbird (Mimus polyglottos) nests that were
monitored with continuous-running video cameras (8,353.9 hrs sampled). As
predicted, higher rates of SOTN significantly decreased daily survival
rates of nests. SOTN occurred almost exclusively by females during the egg
stage and in 86% (48/56) of nests for which we had sampling from the egg
stage. While extensive at the population level, the average rate of SOTN
per individual was very low (5.24 ± 1.24 s SOTN per hr video sampled). We
found mixed support for the hypothesis that SOTN functions in territory
maintenance. We found no support for the hypotheses that SOTN functions to
coordinate parental care, defend nests, or aid in vocal learning. Given
the limited attention SOTN has received and the mostly anecdotal accounts
of it, our understanding of its costs and benefits is lacking. We conclude
that while individual rates of SOTN are quite low, SOTN may be more
widespread in populations than previously thought and that studies
specifically designed to test hypotheses regarding potential functions are
critically needed.