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I encourage everyone that has an interest in predator removal affects to read this article.https://bioone.org/journals/Wildlif...-bobwhite-reproduction/10.2981/wlb.00357.full
For those that don't have the time and want a somewhat shortened version, this is what the article said...
* Predation is the largest source of mortality among avian populations (Ricklefs 1969, Martin 1993, Thompson 2007, Conner et al. 2010).
* Early avian life stages are particularly vulnerable to predation mortality (O'Conner 1991, Coté and Sutherland 1997).
* High levels of nest predation can limit avian recruitment and reduce population growth (Cowardin et al. 1985).
* Because ground-nesting birds are particularly susceptible to nest predation by meso-mammals (Rogers and Heard 2000, Jimenez and Conover 2001), managers are often interested in manipulating this predator community to enhance avian reproduction and population densities (Coté and Sutherland 1997, Ellis-Felege et al. 2012).
* Trapping was effective at reducing predator activity.
* Nests were 1.33 times more likely to be successful on trapped sites than non-trapped sites Fig.1.
* for every 100 hens they produced 14 more nests on trapped sites Fig. 2).
* for every 100 hens they produced 12 more broods (Fig. 3).
* for every 100 hens they produced 109 more chicks on trapped sites Fig. 4).
* Furthermore, we did not find a negative effect between residual predators and chicks hen-1 among trapped sites.
* We found support that predation limits bobwhite reproduction by reducing nest success, nests hen-1, broods hen-1 and chicks hen-1.
* After controlling for predator removal (i.e. sub-setting analysis to only trapped sites), we did not detect a negative relationship between residual predator activity and reproduction suggesting that trapping was effective at reducing predation.
* We found trapped sites to have a lower average predator index than non-trapped sites, suggesting that MMTR reduces predator activity.
* Collectively, our results suggest management of meso-predators to improve reproduction is feasible when habitat resources are not deficient...
* Bobwhite population growth is most sensitive to the variation in reproductive demographics (Sander**** 2006, Stahl and Oli 2006); thus, it is reasonable to believe that the increases in reproduction, especially nests hen-1, broods hen-1 and chicks hen-1, we observed would lead to population growth.
* Meso-mammal trap and removal is effective at reducing meso-mammal populations within a year, but annual implementation is likely required to impede their reestablishment upon cessation of trapping (Tapper et al. 1996, Ellis-Felege et al. 2010). * MMTR is an effective tool for bobwhite managers, however, it should be used under appropriate conditions within a holistic management regime. That is, MMTR should complement other management actions, as habitat management is fundamental to bobwhite management (Stoddard 1931, Rosene 1969, Brennan 1991).
* We found support that trapping reduced meso-mammals to a level that residual predators were not limiting bobwhite reproduction.
* This study was conducted on sites with a long history of bobwhite management and maintaining consistently high abundance compared to other areas throughout the range of bobwhites (Stribling and Sisson 2009, Terhune et al. 2007). Therefore, where habitat is limited, meso-mammal populations could be different and the effects of trapping on bobwhite reproduction could be different as well.
* In areas where habitat is managed intensively and resources (i.e. food and cover) are not likely limited, bobwhite population performance may be limited by meso-mammal predation pressure.
* As such, managers focused on maximizing bobwhite populations should consider meso-mammal trap and removal as a tool to reduce predation pressure attributed to meso-mammals, especially during habitat restoration phases of management.
* Given that meso-predators can recolonize rapidly and are capable of high reproduction, annual application of MMTR may be required to mitigate reestablishment of predator communities upon cessation of trapping.
* Meso-mammal trap and removal should complement other management actions, and be used following or in conjunction with habitat management.
For those that don't have the time and want a somewhat shortened version, this is what the article said...
* Predation is the largest source of mortality among avian populations (Ricklefs 1969, Martin 1993, Thompson 2007, Conner et al. 2010).
* Early avian life stages are particularly vulnerable to predation mortality (O'Conner 1991, Coté and Sutherland 1997).
* High levels of nest predation can limit avian recruitment and reduce population growth (Cowardin et al. 1985).
* Because ground-nesting birds are particularly susceptible to nest predation by meso-mammals (Rogers and Heard 2000, Jimenez and Conover 2001), managers are often interested in manipulating this predator community to enhance avian reproduction and population densities (Coté and Sutherland 1997, Ellis-Felege et al. 2012).
* Trapping was effective at reducing predator activity.
* Nests were 1.33 times more likely to be successful on trapped sites than non-trapped sites Fig.1.
* for every 100 hens they produced 14 more nests on trapped sites Fig. 2).
* for every 100 hens they produced 12 more broods (Fig. 3).
* for every 100 hens they produced 109 more chicks on trapped sites Fig. 4).
* Furthermore, we did not find a negative effect between residual predators and chicks hen-1 among trapped sites.
* We found support that predation limits bobwhite reproduction by reducing nest success, nests hen-1, broods hen-1 and chicks hen-1.
* After controlling for predator removal (i.e. sub-setting analysis to only trapped sites), we did not detect a negative relationship between residual predator activity and reproduction suggesting that trapping was effective at reducing predation.
* We found trapped sites to have a lower average predator index than non-trapped sites, suggesting that MMTR reduces predator activity.
* Collectively, our results suggest management of meso-predators to improve reproduction is feasible when habitat resources are not deficient...
* Bobwhite population growth is most sensitive to the variation in reproductive demographics (Sander**** 2006, Stahl and Oli 2006); thus, it is reasonable to believe that the increases in reproduction, especially nests hen-1, broods hen-1 and chicks hen-1, we observed would lead to population growth.
* Meso-mammal trap and removal is effective at reducing meso-mammal populations within a year, but annual implementation is likely required to impede their reestablishment upon cessation of trapping (Tapper et al. 1996, Ellis-Felege et al. 2010). * MMTR is an effective tool for bobwhite managers, however, it should be used under appropriate conditions within a holistic management regime. That is, MMTR should complement other management actions, as habitat management is fundamental to bobwhite management (Stoddard 1931, Rosene 1969, Brennan 1991).
* We found support that trapping reduced meso-mammals to a level that residual predators were not limiting bobwhite reproduction.
* This study was conducted on sites with a long history of bobwhite management and maintaining consistently high abundance compared to other areas throughout the range of bobwhites (Stribling and Sisson 2009, Terhune et al. 2007). Therefore, where habitat is limited, meso-mammal populations could be different and the effects of trapping on bobwhite reproduction could be different as well.
* In areas where habitat is managed intensively and resources (i.e. food and cover) are not likely limited, bobwhite population performance may be limited by meso-mammal predation pressure.
* As such, managers focused on maximizing bobwhite populations should consider meso-mammal trap and removal as a tool to reduce predation pressure attributed to meso-mammals, especially during habitat restoration phases of management.
* Given that meso-predators can recolonize rapidly and are capable of high reproduction, annual application of MMTR may be required to mitigate reestablishment of predator communities upon cessation of trapping.
* Meso-mammal trap and removal should complement other management actions, and be used following or in conjunction with habitat management.
