Parental care is a widespread phenomenon observed in many diverse taxa and is an important component of fitness. Birds are the largest parental vertebrate clade as 98% of avian species provide some variation of parental care. Despite this, we still know surprisingly little about the neuroendocrine regulation of avian parental care. Neuroendocrine systems have long been thought to play an important role in the onset of parental care as they are known to regulate various aspects of both physiology and behavior. In virtually all birds that raise altricial young, circulating prolactin (PRL) levels are generally low during non-breeding times, but significantly increase during late incubation and early post-hatch care. Because of this pattern, PRL has been suggested to be involved in the initiation of parental care in birds, but rarely has this hypothesis been causally tested. This dissertation provides the first descriptive studies of PRL’s relationship with breeding cycle stages and reproductive experience (chapter 1) and the relationship between PRL and variation in post-hatch parental behavior (chapter 2) in the socially monogamous and biparental zebra finch. In chapters 3 and 4, we provide the first causal evidence that PRL plays a role in the onset of zebra finch parental behavior and show that reproductive experience positively affects parental behavior. Lastly, in chapter 5, we provide the first description of the central PRL receptor (PRLR) in the brains of male and female zebra finches and show how the PRLR distribution is significantly affected by breeding status by comparing the PRLR distribution between breeding and non-breeding brains. This information is essential for continuing to test for a causal role in central PRL in parental care, for generalizing the role of PRL to other avian species, and for comparative analyses to help elucidate the evolution of parental care and other PRL-mediated behaviors.