Metabolic Rates and Parental Feeding of Male and Female Nestlings

高蒂博士发现，性别会影响照顾孩子的成年鸟(假定为父母)和东部蓝知更鸟雏鸟之间的互动：父亲喂女儿的次数比喂儿子的次数多。这是因为女儿比儿子需要更多的能量吗？高蒂博士将检验这一假设，即女儿比儿子需要更多的能量才能长到相同的体型和体重。性别偏向摄食发生在那些已经探索了性别相互作用的鸟类物种中，但这种性别影响的直接原因还没有被评估。东部蓝鸟为有效研究这种影响提供了机会，因为雏鸟(与其他物种不同)可以通过初级翅膀羽毛的颜色来确定性别，而且通过在巢箱中拍摄可以很容易地收集到关于父母和雏鸟如何互动的数据。双标记水法是一种成熟的测量野生动物代谢率的技术。高蒂博士将使用这项技术来评估幼鸟一生中不同年龄段的儿子和女儿的代谢率。如果女儿没有比儿子有更高的代谢率，那么为什么父亲喂女儿的食物比儿子多，这就需要进一步的调查。这一研究项目的发现将是重要的，因为这是首次尝试测量野生鸟类子女的新陈代谢差异，这些信息对于理解鸟类父母的养育模式至关重要。无论儿子和女儿的代谢率是否不同，答案都将有助于阐明鸟类父母照料的原因和控制。

Dr. Gowaty has discovered that gender affects interactions between caregiving adults (presumed parents) and nestling eastern bluebirds: Fathers feed their daughters more often than they feed their sons. Is this because daughters have greater energy requirements than sons? Dr. Gowaty will test the hypothesis that daughters need more energy than do sons to grow to the same size and weight. Gender-biased feeding occurs in those bird species in which gender interactions have been explored, but the proximate causation of such gender effects has not been evaluated. Eastern bluebirds provide an opportunity for efficient study of such effects because nestling bluebirds (unlike other species) can be assigned to gender simply by the color of the primary wing feathers, and because data on how parents and nestlings interact can be readily collected by filming inside a nest box. The doubly-labeled-water method is a well-established technique for measuring metabolic rates of animals living in the wild. Dr. Gowaty will use this technique to evaluate the metabolic rates of sons and daughters at various ages throughout nestling life. If daughters do not have higher metabolic rates than sons, the explanation for why fathers feed their daughters more than their sons will require additional investigation. The findings of this research project will be important, if only because it is the first attempt to measure metabolic differences of sons and daughters of wild-living birds, information that is critical to understanding patterns of parental care by avian parents. Whether or not sons and daughters differ in metabolic rates, the answer will be useful for elucidating the causation and control of parental care in birds.