Protecting northern bobwhite nests from mammalian predators in areas inhabited by the red imported fire ant

Date

2002-08

Journal Title

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Publisher

Texas Tech University

Abstract

Northem bobwhites {Colinus virginianus) have been declining through much of their range over the last 30 years (Sauer et al. 1997). In Texas, northern bobwhite abundance is highly negatively correlated with year of red imported fire ant {Solenopsis invicta) (RIFA) invasion of the county (Allen et al. 1995). As such, RIFA have been implicated as a factor of quail decline. Previous research indicated RIFA control can increase quail population density, but the cause of this relationship was unclear (Allen et al. 1995). RIFA have been found to reduce body mass of chicks in the lab (Giuliano et al. 1996), alter daily activity budgets of chicks (Pederson 1996), and kill pipping and newly pipped chicks (Mueller et al. 1999). Application of Amdro® has been used to successfully mitigate the effects of RIFA on quail nests and pipping chicks (Mueller et al. 1999). Treated nests reached success levels equaling those in areas not inhabited by RIFA.

One possible method to increase quail populations is to protect nests from vertebrate predators. Removal of predators has not conclusively increased quail abundance (Frost 2000, Guthery 1977, Lehmann 1984). Predator exclusion, however, has been highly effective in increasing nest success of ducks {Anas spp.) (Cowardin et al. 1998), piping plovers {Charadrius melodus) (Melvin et al. 1992), and sea turtles {Caretta caretta) (Ratnaswamy et al. 1997). Fencing or screening out mammalian predators can be an effective method for non-lethally reducing their impacts on nest success.

This study was undertaken to develop and implement an experimental technique for increasing northern bobwhite nest success. The objectives were to utilize a non-lethal method of reducing predator impacts, evaluate its effectiveness, and monitor any alterations in nesting behavior caused by this new technique. Additionally, I wanted to evaluate whether increased nest success would lead to increased chick recruitment.

Concurrently, I conducted two other experiments examining the effects of two commonly used RIFA baits. Amdro® and Extinguish® were compared in their ability to reduce RIFA and maintain long-lasting suppression. Both insecticides were evaluated to determine any increase they caused in vegetative biomass, since both use a N containing compound as a carrier for their active ingredients.

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