Reproductive Strategies Of Common Eiders (Somateria Mollissima)

• Main Author: Hervey, Samuel Donald
• Format: Text
• Language: unknown
• Published: UND Scholarly Commons 2019
• Subjects: Behavioral Ecology; Common Eider; Fragment Analysis; Nest Parasitism; Nest Success; Phenology; Somateria mollissima; Wapusk national park
• Online Access: https://commons.und.edu/theses/2460; https://commons.und.edu/context/theses/article/3461/viewcontent/Hervey_und_0156M_11475.pdf

Many reproductive strategies exist all with the same goal to maximize fitness. Because reproductive strategies affect fitness directly, there is interest to understand how they are utilized within a population. The two main strategies we focus on for this work related to Common Eiders (Somateria mollissima) are the utilization of conspecific brood parasitism as an alternative tactic beyond simply nesting and their ability to shift timing of breeding to align young with the best opportunity for survival. To accomplish studying our two reproductive strategies we monitored the Mast and WaWao Common Eider colonies located within Wapusk National Park, Manitoba. Our first aim was understanding conspecific brood parasitism or brood parasitism, which is the act of laying ones eggs (parasitizer) in the nest of another female (host), within the same species. Our objectives were to estimate the rate of brood parasitism using microsatellite loci, identify if non-random spatial and genetic distributions exist in our colonies, and if the relatedness between hosts and parasitizers are more related on average than females nesting in the general vicinity. We estimated the overall rate of brood parasitism to be 22.7% (176 of 775 offspring) with 50.7% (104 of 205 nests) of all nests containing at least one parasitic egg. We found a correlation between pairwise distance and relatedness, but it varied by year and colony. In addition, we did observe some cases of positive local autocorrelation between a focal female and her four nearest neighbors, but we observed negative local autocorrelation as well. Therefore, evidence of kin grouping is present, but not strong. The average pairwise relatedness of hosts and parasitizers, in 2016 (0.083), did not exceed the smallest spatial scale group’s average pairwise relatedness (0.152). However, average pairwise relatedness of host-parasitizer’s, in 2017 (0.308), was higher when compared to even the smallest spatial scale of 0-10 meters (-0.003). This indicates females potentially shift their ...