Evaluating taste aversion as a management tool to reduce nest predation of beach-nesting birds

Graduation Date

2015

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Natural Resources: Wildlife, 2015

Committee Chair Name

Mark A. Colwell

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Camp Pendleton, Conditioned taste aversion, Common raven, Carbachol, Predator management, Snowy plover, Daily nest survival, Humboldt State University -- Theses -- Wildlife, Least tern

Abstract

Nest predation is often a limiting factor in the recovery of threatened and endangered bird species, especially in ground-nesting birds. A variety of predator management techniques are used to reduce the impact of predation on listed species. I examined the efficacy of conditioned taste aversion, a nonlethal management technique designed to induce an avoidance behavior in predators after being exposed to prey items that have been tainted, usually with a chemical emetic. I used carbachol (carbamylcholine chloride) as a taste-aversive agent to condition predators responsible for high levels of nest predation on two listed species, the western snowy plover (Charadrius nivosus nivosus) and California least tern (Sternula antillarum browni), breeding at Marine Corps Base Camp Pendleton in southern California. Between 7 February and 18 March 2013, I deployed 772 artificial nests containing quail (Coturnix spp.) eggs into eight study plots located across approximately 10 km of ocean-fronting beach. During the first two-week stage of the study, when all (n = 160) of the nests only contained untreated quail eggs, nest predation was high, with 90% of nests failing within 1-2 days of deployment. I deployed carbachol-treated eggs into artificial nests during the second and third two-week stages of the study, and daily survival rates increased dramatically between the first stage (0.47±0.022), second stage (control = 0.74±0.016, treatment = 0.94±0.0072), and third stage (control = 0.90±0.015, treatment = 0.98±0.0028). The common raven (Corvus corax) was the most important predator of terns and plovers at Camp Pendleton, accounting for 462 artificial nest predations (98.1% of all nest predations). Using carbachol as a taste-aversive agent was an effective means of reducing predation on artificial nests as illustrated by improved daily survival rates. Further studies should be conducted to determine the transferability of this technique to plover and tern nests.

https://scholarworks.calstate.edu/concern/theses/j098zd28k

Link to Full Text

Share

 
COinS