Data from: Mesotocin influences pinyon jay prosociality.

Many species exhibit prosocial behavior, in which one individual’s actions
benefit another individual, often without an immediate benefit to itself.
The neuropeptide oxytocin is an important hormonal mechanism influencing
prosociality in mammals, but it is unclear whether the avian homologue
mesotocin plays a similar functional role in birds. Here, we
experimentally tested prosociality in pinyon jays (Gymnorhinus
cyanocephalus), a highly social corvid species that spontaneously shares
food with others. First, we measured prosocial preferences in a prosocial
choice task with two different payoff distributions: Prosocial trials
delivered food to both the subject and either an empty cage or a partner
bird, whereas Altruism trials delivered food only to an empty cage or a
partner bird (none to subject). In a second experiment, we examined
whether administering mesotocin influenced prosocial preferences. Compared
to choices in a control condition, we show that subjects voluntarily
delivered food rewards to partners, but only when also receiving food for
themselves (Prosocial trials), and administration of high levels of
mesotocin increased these behaviors. Thus, in birds, mesotocin seems to
play a similar functional role in facilitating prosocial behaviors as
oxytocin does in mammals, suggesting an evolutionarily conserved hormonal
mechanism for prosociality.

诸多物种均存在亲社会行为（prosocial behavior），即某一个体的行为可使另一个体获益，且自身往往无法立即获得回报。神经肽催产素（neuropeptide oxytocin）是调控哺乳动物亲社会行为的重要激素机制，但目前尚不清楚鸟类体内的同源肽类——中催产素（mesotocin）是否在鸟类中发挥类似功能。本研究针对矮松鸦（Gymnorhinus cyanocephalus）——一种高度社会化的鸦科（corvid）物种，且会自发与同类分享食物——的亲社会行为开展了实验测试。首先，我们通过两种不同报酬分布的亲社会选择任务（prosocial choice task），测定了矮松鸦的亲社会偏好：亲社会试次中，实验个体的选择会为自身与另一空置笼舍或同伴个体投喂食物；而利他试次中，选择仅会为空置笼舍或同伴个体投喂食物（实验个体无任何食物收益）。在第二项实验中，我们探究了施加中催产素是否会影响实验个体的亲社会偏好。相较于对照组的选择结果，本研究发现实验个体仅会在自身也能获得食物的亲社会试次中，主动为同伴投喂食物；且高剂量的中催产素给药可增强此类行为。综上，在鸟类体内，中催产素似乎发挥着与哺乳动物体内催产素类似的、促进亲社会行为的功能，这表明亲社会行为的激素调控机制在演化上具有保守性。