The influence of prenatal versus postnatal conditions
on the physiology of 5 day old kittiwake chicks
Author:
Tyler McMasters ’27Co-Authors:
Maria Pisciotta, Morgan Benowitz-FredericksFaculty Mentor(s):
Morgan, Benowitz-Fredericks, BiologyFunding Source:
Douglas K. Candland Undergraduate Research FundAbstract
The Black Legged Kittiwake (Rissa tridactyla) is a species of Arctic seabird that breeds on coastal cliffs and usually raises two chick broods. Similar to other bird species, kittiwake egg size is correlated with hatchling mass. In older chicks, mass can also be correlated with physiology, including metabolite and hormone levels. However, it is not yet known whether this relationship is due to early postnatal experiences that shape both mass and metabolic and hormonal functions, or whether these aspects of physiology may be predetermined by maternal investment in the egg. If the prenatal experience is the cause of the mass-physiology relationship, then egg mass will be a better predictor of ketone and corticosterone levels than chick mass at 5 days old. We also manipulated the postnatal environment by providing food supplementation to some nests, allowing us to further test the role of post-natal experience in shaping physiology. Experiments conducted on Middleton Island, AK in 2024 studied kittiwake chicks from nests that were provided with food supplementation 3x/day, and control nests that were not supplemented. We measured egg size and mass, as well as chick mass, and corticosterone and ketone levels on day 5 post-hatch. By comparing the ability of egg size versus chick mass to explain ketone and corticosterone levels and survival in both control and experimentally fed nests, our study will provide insight into whether variation in physiology and survival in young chicks is more strongly influenced by prenatal investment or postnatal experiences.