Song sparrows, top carnivores and nest predation: a test of the mesopredator release hypothesis

Oecologia ◽  
1998 ◽  
Vol 116 (1-2) ◽  
pp. 227-233 ◽  
Author(s):  
C. M. Rogers ◽  
M. J. Caro
Keyword(s):  
Nest Predation ◽  
Mesopredator Release ◽  
Song Sparrows

Nest Predation and Cowbird Parasitism Create a Demographic Sink in Wetland-Breeding Song Sparrows

The Condor ◽  
1997 ◽  
Vol 99 (3) ◽  
pp. 622-633 ◽  
Author(s):  
Christopher M. Rogers ◽  
Mary J. Taitt ◽  
Gwen Jongejan
Keyword(s):  
Nest Predation ◽  
Song Sparrows ◽  
Cowbird Parasitism

scholarly journals First Evidence of Conspecific Brood Parasitism and Egg Ejection in Song Sparrows, With Comments on Methods Sufficient to Document These

The Condor ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 452-458
Author(s):  
Quresh S. Latif ◽  
J. Letitia Grenier ◽  
Sacha K. Heath ◽  
Grant Ballard ◽  
Mark E. Hauber
Keyword(s):  
Genetic Analysis ◽  
Brood Parasitism ◽  
Nest Predation ◽  
Molothrus Ater ◽  
Separate Study ◽  
Conspecific Brood Parasitism ◽  
Egg Ejection ◽  
Song Sparrows ◽  
Cowbird Parasitism ◽  
Egg Marking

Abstract Conspecific brood parasitism occurs in many songbird species but has not been reported in Song Sparrows (Melospiza melodia). In three separate study areas where breeding Song Sparrows experience heavy nest predation pressure and Brown-headed Cowbird (Molothrus ater) parasitism, we observed six instances in which newly laid eggs were attributable to female Song Sparrows other than the nest owners. We also recorded the ejection of a sparrow egg from each of two videotaped nests. In a fourth study area without cowbird parasitism, genetic analysis of parentage revealed no conspecific brood parasitism. Given that egg ejection can accompany conspecific parasitism in Song Sparrows, we suggest that daily nest checks are insufficient to document the frequency of this tactic in some species in the absence of egg marking, videotaping, or genetic analyses. Since standard nest monitoring techniques may fail to detect conspecific brood parasitism, this behavior could be more prevalent than currently thought.

scholarly journals Reassessing the Cowbird Threat

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 210-223
Author(s):  
Liana Zanette ◽  
Daniel T. Haydon ◽  
James N. M. Smith ◽  
Mary J. Taitt ◽  
Michael Clinchy
Keyword(s):  
Nest Predation ◽  
Molothrus Ater ◽  
Nest Survival ◽  
Survival Rates ◽  
Song Sparrows ◽  
Parasitism Rates ◽  
Common Technique ◽  
Stochastic Simulation Model ◽  
The Common ◽  
Egg Removal

Abstract The demographic significance of parasitism by Brown-headed Cowbirds (Molothrus ater; hereafter “cowbirds”) has been debated for years, because manipulative studies are few and mathematical models of cowbird-host systems have not led to tests of their predictions. We combine results from a cowbird- removal experiment (Smith et al. 2002, 2003) with a stochastic simulation model that we developed, to reassess the effect of cowbirds on the annual reproductive success (ARS) and nesting success in Song Sparrows (Melospiza melodia). Our model followed the breeding success of individual Song Sparrow nests and extrapolated to output variables including ARS, nest survival, and parasitism rates. We parameterized the model with field data from cowbird control sites (i.e., cowbirds not manipulated) and found that output variables matched those observed. We used the reduced parasitism rates observed on cowbird-removal sites, reran the model, and compared output with observed values. On removal sites, ARS was greater than predicted by the model, which indicates that the model failed to account for some biological phenomenon that occurred when cowbirds were in the system. To assess what this phenomenon might be, we conducted further analyses that indicated that cowbirds may facilitate nest predation by “conventional” predators. Using elasticity analyses, we show that cowbirds have their largest effect on ARS through egg removal and that conventional predators are more important than cowbirds in directly affecting nest survival rates. We report that to assess the effect of cowbirds on nest survival, researchers must avoid using the common technique of comparing survival rates of parasitized and unparasitized nests within populations. Réévaluation de la Menace du Vacher

Nest-predation at the edge: an experimental study contrasting two types of edges in the dry Chaco, Paraguay

Ecography ◽  
2001 ◽  
Vol 24 (6) ◽  
pp. 742-750 ◽  
Author(s):  
Lena M. Eriksson ◽  
Lars Edenius ◽  
Veronika Areskoug ◽  
Dennis A. Meritt Jr
Keyword(s):  
Experimental Study ◽  
Nest Predation

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

Geographic Song Discrimination in Relation to Dispersal Distances in Song Sparrows

2002 ◽  
Vol 159 (3) ◽  
pp. 221
Author(s):  
Searcy ◽  
Nowicki ◽  
Hughes ◽  
Peters
Keyword(s):  
Song Sparrows ◽  
Song Discrimination ◽  
Dispersal Distances
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