Red-cockaded Woodpeckers: a ‘primitive’ cooperative breeder

Walters, Jeffrey R.

doi:10.1017/cbo9780511752452.004

Cited by 154 publications

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“…When more such vacancies are available, capacity to occupy recruitment clusters is reduced. Also, rate of retention of breeding males can be viewed as a survival estimate, because breeding males almost never disperse (Walters 1990). Annual variation in survival is not highly correlated among different status classes in RCWs (e.g., Walters et al 2005), so breeding male survival is not a reliable indicator of the survival of the helpers, floaters and fledglings that occupy recruitment clusters.…”

Section: Results and Discussion Population Growthmentioning

confidence: 99%

“…The donor plots provide the only estimates of theses two parameters, as well as an additional estimate of group size. We recognize however that estimates from the donor plots may not be representative of the entire population, because on the donor plots group sizes are reduced by removal of juveniles that could potentially become helpers for translocation, and group size affects productivity (Walters 1990) and breeder survival (Khan and Walters 2002). Nevertheless estimates from the donor plots are useful as indicators of trends over time.…”

Section: Results and Discussion Population Growthmentioning

confidence: 99%

“…The species has declined due to habitat loss and alteration of remaining habitat, specifically loss of old growth pine and development of hardwood midstory due to fire suppression (Walters 1991;USFWS 2003). It has been extensively studied, for example it has been the subject of four symposia (Thompson 1971;Wood 1983;Kulhavy et al 1995;Costa and Daniels 2004) and two books (McFarlane 1992;Conner et al 2001), and its biology is well known (Walters 1990;Jackson 1994;USFWS 2003).…”

Section: Assessment Of Red-cockaded Woodpecker Managementmentioning

confidence: 99%

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Studies of FAUNA at Eglin Air Force Base

Walkers¹,

Haas²,

Blanc³

et al. 2006

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. (From -To) REPORT DATE (DD-MM-YYYY) 01-07-2006 REPORT TYPE Annual DATES COVERED PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBERVirginia Polytechnic Institute Blacksburg, Virginia 24060-3325 SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) U.S. Army Medical Research and Materiel Command Fort Detrick, Maryland 21702-5012 SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for Public Release; Distribution Unlimited SUPPLEMENTARY NOTES ABSTRACTSee Executive Summary Page 2 SUBJECT TERMSNo subject terms provided. ACKNOWLEDGMENTSWe thank the Department of Defense, Natural Resources Division (Jackson Guard), Eglin Air Force Base, for funding this project. Personnel at Eglin were uniformly supportive of and helpful with our work. We thank Range Control for working with us on a daily basis to provide safe access to research sites. We are especially grateful to the members of Jackson Guard for their willingness and ability to coordinate management of the base with our research activities, and for their contributions to the research. The work described here was truly a joint venture between our university research team and Jackson Guard. Several members of Jackson Guard deserve special mention. Dennis Teague contributed to collection of field data. First Carl Petrick and then Bruce Hagedorn provided leadership and input to study design, and secured funding for the project each year. In the early years of the project Bruce managed much of the data and facilitated coordination between our research and other management activities on Eglin. Kathy Gault led our university research team in the early years of the project and continued to contribute to data collection and performance of management activities, as well as managing some of the data and coordinating our work with base natural resource management, after moving to Jackson Guard. Bruce and Kathy participated in annual reviews of population data and a variety of other activities, and generally contributed to the project on a daily basis.We are also indebted to o...

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Section: Results and Discussion Population Growthmentioning

confidence: 99%

Section: Results and Discussion Population Growthmentioning

confidence: 99%

Section: Assessment Of Red-cockaded Woodpecker Managementmentioning

confidence: 99%

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Studies of FAUNA at Eglin Air Force Base

Walkers¹,

Haas²,

Blanc³

et al. 2006

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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%

“…Thus when recruitment clusters are being used to stimulate population growth, productivity, unlike breeder mortality, can impact growth rates. Typically there is a time lag in this effect as many members of a large cohort do not immediately transition from juveniles to breeders but instead spend a year or two as helpers and floaters before dispersing to form new breeding groups (Walters 1990). Indeed such an effect of productivity was evident in the simulations we ran in our previous study in a projected 10% increase in annual population growth rate when productivity was increased by 0.7 fledglings per group (Walters et al 2001).…”

Section: Analysis Of Demographymentioning

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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Do mothers prefer helpers or smaller litters? Birth sex ratio and litter size adjustment in cotton‐top tamarins (Saguinus oedipus)

Boulton

Fletcher

2015

Ecology and Evolution

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Sex allocation theory has been a remarkably productive field in behavioral ecology with empirical evidence regularly supporting quantitative theoretical predictions. Across mammals in general and primates in particular, however, support for the various hypotheses has been more equivocal. Population-level sex ratio biases have often been interpreted as supportive, but evidence for small-scale facultative adjustment has rarely been found. The helper repayment (HR) also named the local resource enhancement (LRE) hypothesis predicts that, in cooperatively breeding species, mothers invest more in the sex which assists with rearing future offspring and that this bias will be more pronounced in mothers who require extra assistance (i.e., due to inexperience or a lack of available alloparents). We tested these hypotheses in captive cotton-top tamarins (Saguinus oedipus) utilizing the international studbook and birth records obtained through a questionnaire from ISIS-registered institutions. Infant sex, litter size, mother's age, parity, and group composition (presence of nonreproductive subordinate males and females) were determined from these records. The HR hypothesis was supported over the entire population, which was significantly biased toward males (the “helpful” sex). We found little support for helper repayment at the individual level, as primiparous females and those in groups without alloparents did not exhibit more extreme tendencies to produce male infants. Primiparous females were, however, more likely to produce singleton litters. Singleton births were more likely to be male, which suggests that there may be an interaction between litter size adjustment and sex allocation. This may be interpreted as supportive of the HR hypothesis, but alternative explanations at both the proximate and ultimate levels are possible. These possibilities warrant further consideration when attempting to understand the ambiguous results of primate sex ratio studies so far.

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Red-cockaded Woodpeckers: a ‘primitive’ cooperative breeder

Cited by 154 publications

References 0 publications

Studies of FAUNA at Eglin Air Force Base

Studies of FAUNA at Eglin Air Force Base

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

Do mothers prefer helpers or smaller litters? Birth sex ratio and litter size adjustment in cotton‐top tamarins (Saguinus oedipus)

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