Honors College

Document Type

Honors Thesis

Publication Date

Spring 2014


Microbial infection has been shown to reduce hatching success for the eggs of tropical birds. In these ecosystems, humidity and temperature encourage bacterial growth and the transport of microbes through the pores of the egg shell. A single study in a temperate ecosystem found no noticeable change of microbial communities during the length of the incubation cycle, and thus no increased risk of microbial infection by the time of hatching. This study, however, took place in the arid Mediterranean type climate of California, a locale that likely diminishes the abilities of microbial communities to colonize and grow on egg surfaces. For this study we explored the ability of microbial communities to colonize and flourish on eggshells in a temperate salt marsh. These temperate ecosystems possess much higher humidity and water exposure than Mediterranean climates, thus possessing conditions that are more conducive to microbial growth. We analyzed the microbial communities of eggs from Saltmarsh (Ammodramus caudacutus) and Nelson's (A. nelsoni) sparrows in a tidal salt marsh in southern Maine. Eggs were swabbed every three days during June and July to test for present microbial communities. To determine if environmental factors affect the microbial community, we compared the microbial environment of eggshells that had and had not been flooded by the tides. We found no significant differences in the microbial communities of these eggshells.