@article{riddle_pollock_simons_2010, title={AN UNRECONCILED DOUBLE-OBSERVER METHOD FOR ESTIMATING DETECTION PROBABILITY AND ABUNDANCE}, volume={127}, ISSN={["1938-4254"]}, DOI={10.1525/auk.2010.09118}, abstractNote={ABSTRACT. Multiple-observer point-count methods allow estimation of detection probability and have some advantages over other point-count methods. We introduce the unreconciled double-observer method, an independent double-observer method that does not require observers to match or otherwise reconcile individual observations. The modeling of the counts uses the repeated-counts model (Royle 2004). We compared estimates of detection probability and abundance from the unreconciled double-observer method with estimates from the traditional independent double-observer method (which requires matching of individual animals) using field-simulated bird-point-count data. The unreconciled double-observer method provided point estimates of detection probability and abundance that were essentially identical to the results of the independent double-observer method, even though much less effort was required to collect data with the unreconciled method. Estimates of detection probability from the unreconciled double-observer method were usually less precise—and estimates of abundance always less precise—than those from the independent double-observer method, because there is less information available in the unreconciled double-observer approach. We also evaluated the unreconciled double-observer method on 12 Breeding Bird Survey (BBS) routes. The unreconciled double-observer method provided estimates of route-level abundance for most routes and for most of the 20 species we considered. We believe that this method has potential for established bird-monitoring programs such as the BBS because no changes in historical data-collection methods are required other than collecting data simultaneously using two or more observers.}, number={4}, journal={AUK}, author={Riddle, Jason D. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2010}, month={Oct}, pages={841–849} }
 @article{riddle_stanislav_pollock_moorman_perkins_2010, title={Separating Components of the Detection Process With Combined Methods: An Example With Northern Bobwhite}, volume={74}, ISSN={["1937-2817"]}, DOI={10.2193/2009-220}, abstractNote={Abstract There are various methods of estimating detection probabilities for avian point counts. Distance and multiple-observer methods require the sometimes unlikely assumption that all birds in the population are available (i.e., sing or are visible) during a count, but the time-of-detection method allows for the possibility that some birds are unavailable during the count. We combined the dependent double-observer method with the time-of-detection method and obtained field-based estimates of the components of detection probability for northern bobwhite (Colinus virginianus). Our approach was a special case of Pollock's robust capture–recapture design where the probability that a bird does not sing is analogous to the probability that an animal is a temporary emigrant. Top models indicated that observers' detection probabilities were similar (0.78–0.84) if bobwhite were available, but bobwhite only had an approximately 0.61 probability of being available during a 2.5-minute sampling interval. Additionally, observers' detection probabilities increased substantially after the initial encounter with an individual bobwhite (analogous to a trap-happy response on the part of the observer). A simulated data set revealed that the combined method was precise when availability and detection given availability were substantially lower. Combined methods approaches can provide critical information for researchers and land managers to make decisions regarding survey length and personnel requirements for point-count–based surveys.}, number={6}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Riddle, Jason D. and Stanislav, Stephen J. and Pollock, Kenneth H. and Moorman, Christopher E. and Perkins, Fern S.}, year={2010}, month={Aug}, pages={1319–1325} }
 @article{riddle_moorman_pollock_2008, title={A comparison of methods for estimating northern bobwhite covey detection probabilities}, volume={72}, DOI={10.2193/2007-435}, abstractNote={Abstract: We compared the time‐of‐detection and logistic regression methods of estimating probability of detection for northern bobwhite (Colinus virginianus) coveys. Both methods are unusual in that they allow estimation of the total probability of detection (i.e., the product of the probability that a covey is available for detection [i.e., that a covey vocalizes] and detection given availability). The logistic regression method produced an average detection probability of 0.596 (SE = 0.020) and the time‐of‐detection method produced a detection probability estimate of 0.540 (SE = 0.086), and the 2 estimates were not significantly different. This is the first evaluation of the time‐of‐detection method with empirical field data. Although the time‐of‐detection and logistic regression method each have advantages, both can be used under appropriate conditions to improve estimates of bobwhite abundance by allowing for the estimation of detection probabilities. Improved estimates of bobwhite abundance will allow land managers to make more informed management decisions.}, number={6}, journal={Journal of Wildlife Management}, author={Riddle, J. D. and Moorman, C. E. and Pollock, K. H.}, year={2008}, pages={1437–1442} }
 @article{riddle_moorman_pollock_2008, title={The importance of habitat shape and landscape context to northern bobwhite populations}, volume={72}, ISSN={["1937-2817"]}, DOI={10.2193/2007-469}, abstractNote={Abstract: Northern bobwhite (Colinus virginianus) populations have declined nationally for at least the past 4 decades. Field borders have been promoted as an important component of conservation plans to reverse this decline. Field border characteristics, such as shape and the landscapes in which the borders are established, have the potential to influence their effectiveness for recovering northern bobwhite populations. We established narrow linear (approx. 3‐m‐wide) and nonlinear field borders on farms in agriculture‐dominated and forest‐dominated landscapes in the Coastal Plain of North Carolina, USA, after collecting pretreatment data on summer bobwhite abundance. After establishment of field borders, summer bobwhite abundance nearly doubled on farms in agriculture‐dominated landscapes and increased approximately 57% on farms with nonlinear field borders. Summer bobwhite abundance did not increase on farms with linear field borders in forest‐dominated landscapes. Nonlinear and narrow linear field borders can be used to increase bobwhite numbers on farms in landscapes dominated by agriculture. Less flexibility exists in forest‐dominated landscapes, where we found only nonlinear field borders resulted in an increase.}, number={6}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Riddle, Jason D. and Moorman, Christopher E. and Pollock, Kenneth H.}, year={2008}, month={Aug}, pages={1376–1382} }