Date of Award

Spring 3-10-2024

Document Type

Thesis

Degree Name

Master of Science in Fisheries and Wildlife Science

Department

Biological Sciences

College

College of Natural & Health Sciences

Committee Chair

Thomas Nupp

Second Committee Member

Jorista Garrie

Third Committee Member

Chris Kellner

Program Director

Thomas Nupp

Dean of Graduate College

Sarah Gordon

Abstract

Causes of colony failure in interior least terns (Sternula antillarum athalassos) have been a prevalent topic for researchers investigating this previously endangered species. In Arkansas, these colonies are primarily located on sandbars formed along the McClellan-Kerr Arkansas River Navigation System. Reduction in nesting site quality may put this sensitive species at a greater risk for predator encounters. In my first chapter, I identified which sandbar characteristics resulted in higher frequencies of predator encounters at interior least tern colonies. In my second chapter, I investigated how those predators influenced colony production and whether interior least tern colonies exhibited similar associations to those site characteristics. I used colony surveys from the summer 2020 and 2021 nesting seasons for my investigations. Commonly identified predators included American crows (Crovus brachyrhynchos), bald eagles (Haliaeetus leucocephalus), coyotes (Canis latrans), domestic dogs (C. familiaris), and northern raccoons (Procyon lotor). I studied fourteen characteristics representative of sandbar morphometrics. Generalized additive models were used to quantify the relationships between those site characteristics and avian predators, mammalian predators, and ILT reproductive success. Interior least tern colonies were located on larger sandbars further away from upriver dams. This study highlights the importance of sandbar size, shape, and location on waterbodies for ILT colony use. These factors were important for ILT production and explaining predator counts at sandbars. This study suggests that, while interior least tern conservation management usually focuses on local habitat features, landscape-scale features may be driving ILT production as well as predator encounters on Arkansas River sandbars.

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