Conspecific Attraction and the Conservation of Territorial Songbirds

Program in Ecology and Evolutionary Biology, University of Illinois, Urbana-Champaign, 61820, Champaign, IL
Conservation Biology (Impact Factor: 4.17). 03/2004; 18(2):519 - 525. DOI: 10.1111/j.1523-1739.2004.00494.x


Conspecific attraction, the tendency for individuals of a species to settle near one another, is well described in colonial species, especially birds. Although this behavior may occur in territorial birds, evidence has been lacking. If territorial birds do exhibit this behavior, it would have major conservation implications. Birds could potentially be attracted to specific sites with artificial stimuli, making conservation of those species more efficient. In 2001 and 2002, we tested whether conspecific attraction occurs in an endangered, territorial songbird, the Black-capped Vireo (Vireo atricapilla) by playing vireo vocalizations in unoccupied habitats at Fort Hood, Texas. We were successful in attracting 73 birds to five experimental sites in 2001 and 75 birds to seven experimental sites in 2002. No birds settled on comparable control sites. Many birds attracted to the vocalizations paired and bred. At most research sites the primary threat to the species, the brood-parasitic Brown-headed Cowbird (Molothrus ater), was controlled, allowing vireos to achieve high nesting success relative to a nearby, unmanipulated population. Second-year birds were more responsive to conspecific vocalizations than older birds, as they were more common on experimental sites than in the established population. In 2002 birds recolonized experimental sites from 2001 where vocalizations were not played in 2002, indicating that 1 year of playbacks may be sufficient to establish a population. Our results provide the first experimental evidence that territorial songbirds use the presence of conspecifics when deciding where to settle and suggest that conspecific attraction may provide a valuable conservation tool.
Resumen: La atracción conespecífica, tendencia de los individuos de una especie a establecerse cerca de otro de la misma especie, está bien descrita en especies coloniales, especialmente aves. Aunque este comportamiento puede ocurrir en aves territoriales, se carece de evidencia. Si aves territoriales muestran este comportamiento, tendría implicaciones mayores en la conservación. Las aves potencialmente serían atraídas a sitios específicos mediante estímulos artificiales, haciendo más eficiente la conservación de esas especies. En 2001 y 2002, probamos si ocurre la atracción conespecífica en una especie de ave canora territorial, en peligro, Vireo atricapilla, con la reproducción de vocalizaciones de vireo en hábitats desocupados en Fort Hood, Texas. Tuvimos éxito al atraer a 73 aves a cinco sitios experimentales en 2001 y 75 aves a siete sitios experimentales en 2002. No se establecieron aves en sitios controles comparables. Muchas de las aves atraídas a las vocalizaciones formaron pareja y se reprodujeron. En la mayoría de los sitios, la principal amenaza para la especie, el parásito Molothrus ater, fue controlada, lo que permitió un elevado éxito de anidación a los vireos en comparación con una población no manipulada cercana. Las aves de dos años tuvieron mayor respuesta a las vocalizaciones conespecíficas que las aves más viejas, porque fueron más comunes en los sitios experimentales que en la población establecida. En 2002 aves recolonizaron sitios experimentales de 2001 en los que no se reprodujeron vocalizaciones en 2002, lo que indica que 1 año de repetición de vocalizaciones puede ser suficiente para establecer una población. Nuestros resultados proporcionan las primeras pruebas experimentales de que aves canoras territoriales utilizan la presencia de conespecíficos al decidir donde se establecen y sugieren que la atracción conespecífica puede ser una valiosa herramienta de conservación.

    • "Power was provided via a lead acid battery (18 Ah 12 V; Scooter) charged by a 50 W solar panel (Renology, RNG 50-P; MPPT charge controller, Genasun GV-5). Songs were housed on an SD card (mp3 format) and played at natural amplitude levels (85 ± 2 dB max amplitude SPL(A) at 1 m from the source; Casella 633 type 1 sound level meter; for natural sound levels see Brenowitz 1982, Brumm 2009) and time intervals (5–15 songs/min) during the hours of peak singing (30 min prior to sunrise—12:00 PM; similar to (Ward and Schlossberg 2004; Hahn and Silverman 2007). A 50-min playback loop was composed of an equal mixture of 1 min segments containing songs from individual species and 1 min mixed segments containing all 6 focal species singing simultaneously such that each remained individually distinguishable. "
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    ABSTRACT: The presence of conspecifics is an indicator of good habitat for a number of songbird species; a cue positively associated with territory selection. Thus, conspecific playback may be a cost-effective tool for attracting songbirds to particular, preselected sites of high-quality habitat. Previous studies have used conspecific playback to encourage the establishment of a single species; however, few have researched the potential for the simultaneous attraction of multiple species. Furthermore, empirical studies on the effect of song playback for nonfocal species are sparse. We investigated whether 6 migratory songbird species are more likely to establish nesting territories in response to multispecies playback. To evaluate the effect on the greater songbird community, we assessed the responses of 22 nonfocal species. Three of 6 focal species increased their use of areas near playback speakers, and none became less common. However, several nonfocal species were less likely to use playback sites. Phylogenetic comparison revealed that species closely related to playback species were those most likely to be affected. Our results suggest that conspecific attraction can be used to attract multiple songbird species simultaneously, but that its impact on nonfocal species should be considered before implementation.
    No preview · Article · Jun 2015 · Behavioral Ecology
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    • "The ability to locate and select high-quality breeding sites is a key behavioural process that links individual fitness to population-and community-level dynamics, including population regulation (Fretwell & Lucas 1970; Pulliam 1988), community assembly (Fletcher 2008; Betts, Nocera & Hadley 2010) and maintaining biological diversity (Ward & Schlossberg 2004). Understanding the cues that individuals use to assess and select breeding sites is thus a central question in ecology, evolution and conservation (Morris 2003; Danchin et al. 2004; Ahlering & Faaborg 2006). "
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    ABSTRACT: The processes by which individuals select breeding sites have important consequences for individual tness as well as population- and community-dynamics. Although there is increasing evidence that many animal species use information acquired from conspecics to assess the suitability of potential breeding sites, little is known about how the use of this social information is modified by biotic and abiotic conditions. We used an automated playback experiment to simulate two types of social information, post-breeding public information and pre-breeding location cues, to determine the relative importance of these cues for breeding site selection by a migratory songbird, the American redstart (Setophaga ruticilla). In addition, we used stable hydrogen isotopes to determine the dispersal status of individuals that responded to our experimental treatments and quantify whether long-distance dispersers use different social cues to select breeding sites compared to philopatric individuals. We found that points that received pre-breeding location cue treatments were signi cantly more likely to be settled by redstarts than control points that received no playback. However, we found no evidence the redstarts used post-breeding public information gathered during one season to select breeding sites the following year. Breeding site habitat structure was also a strong predictor of settlement probability, indicating that redstarts modi ed the use of social information based on habitat cues. Furthermore, stable hydrogen isotope signatures from individuals that responded to location cue treatments suggest that long-distance dispersers may rely more heavily on these cues than local recruits. Collectively, these results indicate that redstarts use multiple sources of information to select breeding sites, which could buffer individuals from selecting suboptimal sites when they breed in unfamiliar locations or when habitat quality becomes decoupled from social cues.
    Full-text · Article · Jun 2015 · Journal of Animal Ecology
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    • "Playback systems are relatively inexpensive and easy to construct, and require little maintenance effort. Playbacks have been used successfully in attracting several species of songbirds (including certain endangered species; Ward and Schlossberg 2004) to unoccupied but suitable habitat, and are now a valuable tool in avian management and conservation (Ahlering et al. 2010). Although we have only reported on the efficacy of playbacks for A. americanus and H. chrysoscelis, we expect that anuran species with comparable breeding ecologies to H. chrysoscelis may respond similarly to conspecific calls. "
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    ABSTRACT: Conspecific cues have been shown to influence habitat selection in many different species. In anurans, conspecific chorus sounds may facilitate location of new breeding ponds, but direct experimental evidence supporting this notion is lacking. We conducted an experimental field study on American toads (Anaxyrus americanus) and Cope’s gray tree frogs (Hyla chrysoscelis) to determine whether toads and tree frogs use acoustic cues to find new breeding areas by broadcasting chorus sounds at artificial ponds. We found that acoustic cues were effective in attracting H. chrysoscelis to ponds; playback ponds were detected by H. chrysoscelis at significantly faster rates and had greater rates of use than control ponds. Anaxyrus americanus did not colonize ponds regardless of the presence of chorus sounds. This study provides some of the first experimental field evidence that anurans use conspecific cues to locate new breeding habitat; however, species with certain life-history traits may be more likely to exhibit this behavior. These findings may have valuable applications to amphibian conservation and management. If certain anuran species use presence of conspecifics to select habitat, managers may manipulate conspecific cues to passively translocate individuals across the landscape to target wetlands.
    Full-text · Article · May 2015 · Behavioral Ecology
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