Nesting Success Is Higher for Polygynously Mated Females Than for Monogamously Mated Females in the Eastern Meadowlark

I compared nesting success of polygynously and monogamously mated females in a population of the Eastern Meadowlark (Sturnella magna). Clutch size, growth rates of nestlings, and mass at fledging of nestlings were not different in the two groups of females. Both hatching success and fledging success were significantly higher, however, for females mated with polygynous males than for those mated with monogamous males. Predation was the major cause of reproductive failure. I suggest that polygynous males are older males that provide better parental care when nest contents are faced with the risks of predation.