Sociality and cooperative breeding of red-cockaded woodpeckers,Picoides borealis

Lennartz, Michael R.; Hooper, Robert G.; Harlow, Richard F.

doi:10.1007/bf00572629

Cited by 86 publications

(44 citation statements)

References 19 publications

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“…This may lead to an underestimate of population density in high-quality habitats. The presence of helpers (Lennartz et al 1987, Beyer et al 1996 and the age of the breeders (Lennartz et al 1987, Walters 1990) are clearly the prime determinants of productivity in Red-cockaded Woodpeckers, however, and we do not expect significant error to arise from an interaction among territory size, habitat quality, and population density.…”

Section: Structural Assumptions Of the Modelmentioning

confidence: 67%

Testing a Spatially Explicit, Individual-Based Model of Red-Cockaded Woodpecker Population Dynamics

Schiegg

Walters

Priddy

2005

Ecological Applications

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Abstract. Stochastic population models are widely used to assess extinction risk under various management scenarios, but due to the lack of independent data, such models are tested only rarely. Here we evaluate the predictive accuracy of a stochastic, spatially explicit, individual-based model of the population dynamics of the Red-cockaded Woodpecker by comparing simulated data with independent empirical data sets from two populations. We examined primary model predictions such as population size and number of territories, and secondary predictions such as population structure, dispersal success, natal dispersal distances, and age distributions. The model predicted most evaluated parameters with high accuracy, but model performance could be enhanced by including pioneering behavior and by improving estimates of male and female dispersal behavior. We judge our model to provide reliable predictions when applied to real populations, with a few specific exceptions.

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Section: Structural Assumptions Of the Modelmentioning

confidence: 67%

Testing a Spatially Explicit, Individual-Based Model of Red-Cockaded Woodpecker Population Dynamics

Schiegg

Walters

Priddy

2005

Ecological Applications

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“…These birds are cooperative breeders and form social units in which nonbreeding adults help the breeding pair to raise their young. A social unit consists of a breeding pair and 0-4 nonbreeding male helpers (Lennartz et al 1987. Female helpers are uncommon.…”

Section: Introductionmentioning

confidence: 99%

Social and Environmental Factors Affect Natal Dispersal and Philopatry of Male Red-Cockaded Woodpeckers

Pasinelli¹,

Walters²

2002

Ecology

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Abstract. Natal dispersal behavior can vary considerably among individuals, but the causes of intraspecific plasticity in dispersal are poorly understood. We tested six hypotheses about social and environmental conditions that might influence natal dispersal of males in the cooperatively breeding Red-cockaded Woodpecker (Picoides borealis). Further, we examined whether variation in dispersal behavior is heritable. Dispersing from the natal territory during the first year rather than remaining as a helper was associated with four factors. First, dispersing male fledglings were, on average, significantly lower in body mass than their philopatric siblings, indicating an influence of social dominance on dispersal. Second, individuals were more likely to disperse from territories with many male fledglings, independent of the number of adult male helpers per territory, suggesting that sibling (rather than helper-offspring) competition for future reproduction may be the underlying mechanism. Third, the probability of remaining as a helper rather than dispersing was positively associated with quality of the natal territory and with the number of high-quality territories close to the natal site. This suggests an influence of the benefits of philopatry, because many males that initially remain as helpers eventually become breeders on the natal territory or a neighboring territory. Finally, we found evidence that ecological constraints influence dispersal: the probability of dispersing was positively related to the availability of vacant territories in the wider neighborhood of the natal site. Natal dispersal behavior was not influenced by resource competition, measured as group size on the natal territory, or by local density, estimated as the number of active territories in the vicinity of the natal site. Based on comparisons of father-son and brother-brother dispersal behavior, we found no evidence for heritability of philopatric behavior. Dispersal of male fledgling Red-cockaded Woodpeckers can be viewed as conditional on social and ecological factors in the natal territory and in the immediate neighborhood. These factors seem to serve as proximate cues that influence young birds to either disperse or remain as philopatric helpers.

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“…In such systems some adults, called helpers, assist others in raising young rather than reproducing themselves. In RCWs, most helpers are previous male offspring of the breeding pair (Ligon 1970;Lennartz et al 1987;Walters et al 1988;Walters 1990). Helpers become breeders by inheriting a breeding position on their natal territory, or dispersing to fill a vacancy on a neighboring one (Walters et al 1988;1992a).…”

Section: Rationale and Backgroundmentioning

confidence: 99%

An experimental study of the impact of location on the effectiveness of recruitment clusters for Red-cockaded Woodpeckers at the Savannah River Site.

Walters¹,

Johnston²,

Crowder³

et al. 2008

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EXECUTIVE SUMMARYThis report summarizes results of a five-year study of red-cockaded woodpeckers (Picoides borealis) at the Savannah River Site (SRS) conducted by biologists from Virginia Tech, the Duke Marine Laboratory and the USDA Forest Service at SRS. This project is based on a previous study in which we showed that growth of the red-cockaded woodpecker (RCW) population at SRS likely was limited by poor dispersal success due to an unfavorable spatial distribution of recruitment clusters. The primary objective of the project was to test experimentally the hypothesis that the location of recruitment clusters relative to existing groups was limiting their rate of occupancy. A secondary objective was to evaluate the cost effectiveness of various elements of the SRS management plan for RCWs.Rates of occupation of two types of recruitment clusters, differing in their spatial relationship to existing woodpecker groups, were compared. Experimental clusters were within 2 km of three or more existing groups, whereas control clusters had no existing groups within 2 km of them. Eight recruitment clusters of each type were established in the winter of [2001][2002], and initial response to them was assessed in the RCW breeding season in 2002. Four of eight experimental recruitment clusters (50%) were occupied in the 2002 breeding season, whereas only one of eight control recruitment clusters (12%) was occupied. Those recruitment clusters that were occupied were replaced by new ones, so that ten recruitment clusters of each type were available for occupancy each breeding season, beginning in 2003. The rate of occupation in 2003 was lower than in 2002, but still higher for experimental clusters (30%) than for control clusters (0%). Rates of occupation fell to near zero after 2003: only one cluster of each type was occupied in 2004 and 2005 combined. At the end of the experiment, seven of the 18 experimental clusters that were constructed were occupied (39%), compared to two of the 11 control clusters (18%). The difference between treatments in occupancy is not statistically significant but the trend in the data supports the idea that placing recruitment clusters near existing groups increases occupancy rate.We predicted that placing recruitment clusters near existing groups would not only increase their rate of occupation, but also result in high rates of population growth and increased rates of transition from non-breeder to breeder status among juvenile females and helper males (due to their achieving breeding status by occupying such clusters). Our prior work showed these transition rates to be unusually low at SRS compared to other RCW populations. The expectation of enhanced population growth was not realized. The population increased by 11% (from 37 to 41 groups) in the first year of the study, a rate of growth similar to that during the period analyzed in our previous study (12% annual growth 1995-1998, from 18 to 25 groups) and the intervening years (14% annual growth 1998-2001, from 25 to 37 groups). However no ad...

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Sociality and cooperative breeding of red-cockaded woodpeckers,Picoides borealis

Cited by 86 publications

References 19 publications

Testing a Spatially Explicit, Individual-Based Model of Red-Cockaded Woodpecker Population Dynamics

Testing a Spatially Explicit, Individual-Based Model of Red-Cockaded Woodpecker Population Dynamics

Social and Environmental Factors Affect Natal Dispersal and Philopatry of Male Red-Cockaded Woodpeckers

An experimental study of the impact of location on the effectiveness of recruitment clusters for Red-cockaded Woodpeckers at the Savannah River Site.

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