Graduation Date

Spring 2022

Document Type



Master of Science degree with a major in Natural Resources, option Wildlife

Committee Chair Name

Mark Colwell

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Jeffrey Black

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Matthew Johnson

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories



Roosts, locations at which birds and other animals come together to rest and preen while remaining vigilant for predators, are a common facet of the nonbreeding biology of many shorebirds. Roosts fall on a continuum from traditional to ephemeral; traditional roosts are used consistently by the same individuals, whereas ephemeral roosts are used inconsistently and may be used only once or a few times. Studies show that roost habitat preference is the result of an individual shorebird’s attempt to optimize the costs and benefits associated with time constraints, energetic demands, and danger risks as they relate to overall fitness.

In this study, I evaluated roost site availability for a population of calidridine sandpipers wintering in Humboldt Bay, California along with the habitat characteristics that influence occurrence at roost sites. I organized a team of observers to conduct coordinated high-tide surveys of Humboldt Bay once per month from November 2018 through February 2019. My dataset included 129,196 observations of sandpipers at 104 roost sites throughout the bay.

My findings revealed that sandpipers occupied a large number of roost sites in diverse habitats. Sandpipers used a majority of these roosts infrequently, suggesting that suitable roosting habitat is readily available and that individuals have many options when choosing roost sites throughout Humboldt Bay. In addition, habitat features influenced distribution among roosts, as individuals selected roost sites with landscape characteristics that balanced competing needs associated with time and energy constraints while minimizing risk of danger posed by predators. Because roosts differ in terms of quality of habitat, there is likely a minimum distribution of ideal roost habitat needed to maintain wintering sandpiper populations throughout Humboldt Bay.

Citation Style

Journal of Wildlife Management

Included in

Ornithology Commons


Thesis/Project Location