Using marsh bird nest survival and post-fledging habitat use and survival to inform wetland management

Schmidt, Stephanie M.

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https://hdl.handle.net/2142/115343 Copy

Description

Title

Using marsh bird nest survival and post-fledging habitat use and survival to inform wetland management

Author(s)

Schmidt, Stephanie M.

Issue Date

2022-03-03

Director of Research (if dissertation) or Advisor (if thesis)

• Benson, Thomas J
• Fournier, Auriel M. V.

Committee Member(s)

Ward, Michael P.

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• marsh bird
• nest survival
• nest predation
• wetland management
• Least Bittern
• Ixobrychus exilis
• fledgling survival
• fledgling habitat use

Abstract

Wetlands have become rare in the United States due to changing land-use practices, contributing to population declines of wetland-dependent birds. Many remaining wetlands are intensively managed through seasonal dewatering mimicking flood pulses in the spring and summer while marsh birds are nesting. However, water around nests may provide protection from predators, and lowering water levels during the breeding season of marsh birds may increase predation risk and exacerbate marsh bird losses. Additionally, the effects of dewatering may have negative implications for fledgling marsh birds who often face the highest risk of mortality due to their inexperience navigating, foraging, and avoiding predators. I studied spatial and temporal factors contributing to marsh bird nest loss and predation risk as a result of wetland dewatering at Least Bittern (Ixobrychus exilis), Common Gallinule (Gallinula galeata), Black-crowned Night-Heron (Nycticorax nycticorax), and American Coot (Fulica americana) nests at Emiquon Preserve in Fulton County, Illinois in 2020 and 2021. Additionally, I examined post-fledging Least Bittern habitat selection and mortality on a dewatered landscape. I found water below and around a nest and the timing and volume of dewatering influenced marsh bird nest survival, with greater survival of nests over deeper water, farther from the shoreline, and when dewatering was later, and less water volume was removed from the marsh. I also found predation risk by raccoons (Procyon lotor) and mink (Neovision vision), and risk of nest abandonment increased as water was removed, suggesting mammalian predators have greater access to nests due to dewatering. I found fledgling habitat use was dependent on age and flight ability, and pre-flight fledging habitat decisions potentially maximized predator protection while post-flight fledgling decisions potentially maximized hunting efficiency. Fledgling mortality was dependent on age, with a bottleneck observed in the first few days following fledging.

Graduation Semester

2022-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Stephanie Schmidt

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