Honors Theses and Capstones

Date of Award

Spring 2023

Project Type

Senior Honors Thesis

College or School

COLSA

Department

Natural Resources and the Environment

Program or Major

Wildlife and Conservation Biology

Degree Name

Bachelor of Science

First Advisor

Adrienne Kovach

Abstract

The saltmarsh sparrow (Ammospiza caudacutus) is a ground-nesting specialist in coastal salt marshes of the Northeast. Rising sea-levels increase the loss of offspring due to tidal flooding, reducing nest success and resulting in a sharp population decline. In other avian species, age has been shown to affect nest success through altering fertility, behavior, and the number of young produced, favoring older individuals. I investigated age effects on nest success of female saltmarsh sparrows using nest monitoring data collected at four sites of a long-term demographic monitoring project: Chapman's Landing (Stratham, NH), Eldridge Marsh (Wells, ME), Popham Beach (Phippsburg, ME), and Maquoit Bay (Brunswick, ME). Reproductive success was measured categorically, based on whether a nest failed entirely or fledged at least one chick, and quantitatively, based on the number of chicks fledged per nest. The causes of failure (flooding or predation) were also observed. Female age was reconstructed using historical banding data. I predicted that older females will have greater quantitative and qualitative reproductive success than younger individuals due to their higher experience level. Similarly, I predict that younger females will be more prone to flooding due to their inexperience. Findings showed a correlation between the age and reproductive success of female saltmarsh sparrows with older females losing a higher proportion of nests to flooding while in the egg stage but fledging a higher proportion of nestlings than younger females. With increased understanding of the effects of aging, demographic surveys could better estimate fecundity and prioritize conserving populations with the greatest growth potential.

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