Reproductive Success of Eastern Bluebirds (Siala sialis) on Suburban Golf Courses

Abstract

Understanding the role of green space in urban-suburban landscapes is becoming critical for bird conservation because of rampant habitat loss and conversion. Although not natural habitat, golf courses could play a role in bird conservation if they support breeding populations of some native species, yet scientists remain skeptical. In 2003-2009, we measured reproduction of Eastern Bluebirds {Siala sialis) in Virginia on golf courses and surrounding reference habitats, of the type that would have been present had golf courses not been developed on these sites (e.g., recreational parks, cemeteries, agriculture land, and college campus). We monitored >650 nest boxes and 2,255 nest attempts {n = 1,363 golf course, n = 892 reference site). We used an information-theoretic modeling approach to evaluate whether conditions on golf courses affected timing of breeding, investment, or nest productivity compared with nearby reference sites. We found that Eastern Bluebirds breeding on golf courses reproduced as well as those breeding in other disturbed habitats. Habitat type had no effect on initial reproductive investment, including date of clutch initiation or clutch size (jc = 4 eggs). During incubation and hatching, eggs in nests on golf courses had higher hatching rates (80%) and brood sizes {x = 4.0 nestlings brood"') than nests on reference sites (75% hatching rate; x = 3.8 nestlings brood"'). Mortality of older nestlings was also lower on golf courses and, on average, golf course nests produced 0.3 more fledglings than nests on reference sites. Thus, within a matrix of human-dominated habitats, golf courses may support productive populations of some avian species that can tolerate moderate levels of disturbance, like Eastern Bluebirds. Éxito Reproductivo de Sialia sialis en Campos de Golf SuburbanosRESUMEN.-Comprender el papel del espacio verde en paisajes urbanos-suburbanos se está haciendo crítico para la conservación de las aves debido a la marcada pérdida y conversión de habitats. Aunque no son habitats naturales, los campos de golf podrían desempeñar un papel en la conservación de las aves si éstos sostienen poblaciones reproductoras de algunas especies nativas, pero los científicos son aun escépticos al respecto. En 2003-2009, medimos la reproducción de Siala sialis en campos de golf en Virgina y en ambientes circundantes de referencia correspondientes al tipo de habitat que habría estado presente si no se hubieran desarrollado los campos de golf en esos sitios (e.g., parques recreacionales, cementerios, áreas agricolas, campus universitario). Monitoreamos más de 650 cajas de anidación y 2255 intentos de anidación (n = 1363 en campos de golf, n = 892 en sitios de referencia). Empleamos un enfoque de modelamiento basado en teoría de la información para evaluar si las condiciones de los campos de golf afectaban el momento en que tenía lugar la reproducción, la inversión reproductiva o la productividad de los nidos en comparación con sitios de referencia cercanos. Encontramos que los individuos que se reproducen en...

Predator guards on nest boxes improve nesting success of birds

“…This is the first large‐scale effort to quantify the influence of installing antipredation devices on nest boxes for cavity‐nesting birds and suggests that installing predator guards is a useful management action. Our study reinforces earlier research focused on single species and restricted geographic scales (Bolen , Cornell et al ).…”

Do Hole-Nesting Passerine Birds Fare Well at Artificial Suburban Forest Edges?

“…In our case, we also estimated reproductive success via the number of offspring per nest, which was also higher at the edges than in the forest, thus we can reject the hypothesis that the studied artificial forest edges acted as ecological traps. Cornell et al (2011) showed that bluebirds (Sialia sialis) do equally well occupying nest-boxes on golf courses than at structurally similar habitats, like parks, hence, the clearly positive edge effect reported here might be true in other human made open environments than golf courses too. The open-edge habitat may provide warmer nesting conditions (Kremsater & Bunnel 1999), as well as foraging areas suitable for these insectivorous species (Cornell et al 2011), which overcome disturbance and predation pressures possibly attributed to the visible nesting sites (Cornell et al 2011).…”

“…Cornell et al (2011) showed that bluebirds (Sialia sialis) do equally well occupying nest-boxes on golf courses than at structurally similar habitats, like parks, hence, the clearly positive edge effect reported here might be true in other human made open environments than golf courses too. The open-edge habitat may provide warmer nesting conditions (Kremsater & Bunnel 1999), as well as foraging areas suitable for these insectivorous species (Cornell et al 2011), which overcome disturbance and predation pressures possibly attributed to the visible nesting sites (Cornell et al 2011). However, increased number of offspring is not necessarily directly and only related to better habitat quality, but it is also possible that edge nesting sites were occupied by better quality/older/more experienced birds, and thus the difference in offspring number reflects parental quality.…”

“…Many studies of birds in golf courses (Gordon et al 2003, Dale 2004, White & Main 2004, Cristol & Rodewald 2005, Merola-Zwartjes & DeLong 2005, Cornell et al 2011 have shown that a golf course can provide suitable habitats for many bird species and, in some cases, can even contain species that are of conservation concern. However, of the studies that have investigated avian responses to golf course habitats, few have used an experimental approach (Cornell et al 2011). In general, experimental studies in urban environments are rare despite the frequent and replicated land transformations conducted by developers (Marzluff & Ewing 2001).…”

“…Based on the literature (Jones et al 2005, LeClerc et al 2005, Cornell et al 2011, we expect such edge habitats to provide a favourable breeding habitat, because of the variable vegetation, access to prey (insects) and good thermal conditions. On the other hand, the open edge habitat might be disturbing for nesting birds and may even attract predators, reducing the reproductive success of birds nesting at forest edges (Dale 2004, Smith et al 2005, Stanback & Seifert 2005.…”