Evaluating Two Trap-and-Release Methods for Bobwhites

Numerous methods exist for capturing northern bobwhite (Colinus virginianus) including various net configurations and baited, wire-funnel traps. The latter represents the most commonly used technique whereby more than 97% of the studies in the current body of literature report using Stoddard’s (1931) standard quail trap for capturing bobwhites. Some researchers, however, employed multiple methods of capture for the same study. Regardless of the technique used, birds are either worked up directly in the field or held overnight and released the next day. Each of these approaches has their distinct advantages and limitations, and may vary with respect to their overall impact on bobwhite behavior and survival germane to stress incurred during capture, handling, and/or transport. Despite the inherent difference in capture and handling time, no known studies have evaluated the influence of these two capture methods on bobwhites. Yet, the tenability of the information gained from research is predicated on the notion that our methods do not influence the individuals being studied. During 2014 – 2015, we captured bobwhites (n = 664) on Tall Timbers Research Station (TTRS, ~1570 ha) using standard funnel traps during fall (Oct/Nov), winter (January) and spring (Mar/April). All birds were leg-banded and one subset (Cohort 1;n =108) was radio-tagged, worked up in the field and release immediately at the capture site and a second subset (Cohort 2;n = 212) was transferred to holding boxes, held overnight and the next morning they were radio-tagged and released nearby the capture site. I evaluated daily survival rate for each of the 4 groups (radio-tagged cohorts, banded-only controls) using Burnham’s joint model in program MARK. Preliminary results indicate the daily survival for cohort 2 was moderately better than cohort 1 but similar to control groups. Additional data will be incorporated upon the completion of March 2016 trapping season

Effect of Field Trials on Northern Bobwhite Survival and Hunt Quality on Dixie Plantation

The potential negative effects of horseback field trials on survival and post trial hunting quality of northern bobwhites (Colinus virginianus) have long been debated. Recent acquisition of Dixie Plantation (3,650 ha) by Tall Timbers Research Station provided a unique opportunity to evaluate this interaction as Dixie has been home to the Continental Field Trial since 1937. We monitored radio-tagged bobwhites annually (n = 183; ~20 coveys during fall/winter) on a core study area (640 ha) upon which a portion of the field trial was conducted during January 2015 & 2016. We estimated Kaplan-Meier survival of radio-tagged bobwhites on Dixie before, during, and after the field trial event as well as compared seasonal survival to bobwhite (N = 387) on nearby Tall Timbers Research Station (1,570 ha) during the same time period. Additionally, we recorded the number of coveys seen, coveys pointed, and shots fired during each half-day hunt (n = 133) to evaluate hunt quality before and after the field trial. Bobwhite survival on Dixie was similar (P\u3e0.05) during the two weeks prior to (0.89, SE = 0.026), during (0.93, SE = 0.023), and after (0.92, SE = 0.026) the field trial for the two years combined, as were seasonal survival curves between the two study sites for both years monitored. No differences (P\u3e0.05) were observed in the number of coveys seen per half day hunt before (X = 11.78, SE = 0.39) compared to after (X = 12.35, SE = 0.44), covey rises shot before (X = 6.89, SE = 0.28) and after (X = 7.75, SE = 0.37), or number of shots fired before (X = 23.5, SE = 1.19) versus after (X =24.11 SE = 1.26) the field trial. We were unable to detect any evidence that the type of disturbance generated by this field trial had any effect on either bobwhite survival or post trial hunting quality on our study area

Use of Spring Whistle Counts to Predict Northern Bobwhite Relative Abundance

Spring whistle counts are commonly used to index northern bobwhite (Colinus virginianus) breeding populations and make inference about relative autumn abundance. They are relatively cheap and easy to implement and provide the advantage of surveying bobwhite populations from multiple points daily and early in the year. This could prove useful on properties available for potential lease, purchase, or as translocation sites; as well as to monitor population trends. Our objective was to determine whether spring whistle counts reliably forecast autumn covey numbers on a wide range of sites, years, and densities on 6 properties in southwestern Georgia from 2006 to 2015. We conducted spring whistle counts weekly during peak calling activity (late May–early Jun, for 4–6 consecutive years) on an average of 7 points/property (range = 5–9). We conducted autumn covey counts using these same sampling points as an index of relative abundance. Peak number of males heard in spring and number of coveys heard in autumn was strongly correlated (R2 = 0.791, n = 198) for all points combined, indicating that spring whistle counts are a reliable tool for assessing bobwhite relative abundance on sites where autumn covey counts are precluded or the information is needed prior to autumn

Evaluating the Impacts of Hunting Paths on Northern Bobwhite Survival, Economic Costs, and Hunter Satisfaction

The amount and spatial configuration of habitat is known to influence the abundance, movements, resource use, and persistence of many species. As such, land managers must be judicious in their application of management actions to minimize its impact on wildlife while concurrently providing recreational opportunities. Mowing or roller-chopping is a common management technique implemented on intensively managed northern bobwhite (Colinus virginianus) plantations to increase hunter accessibility, provide travel corridors for pointing dogs, manage vegetation succession, among other benefits. Managers typically create hunting paths in a grid pattern at 30 ft spacing resulting in approximately 35% of vegetation removed prior to hunting season. However, the optimal spacing for paths is unknown and some concern exists over the presence of paths in general as they may facilitate predation. Our objectives were to determine how different densities of paths (i.e., reduced cover and increased edge) impacted northern bobwhite survival, quantify the costs per hectare of paths, and determine hunter satisfaction. We developed two path treatments (30 ft and 90 ft spacing) and a control (no paths) on Tall Timbers Research Station in Leon County, Florida. We radio-tagged a subset of northern bobwhites (n = 150), equally distributed within each treatment, and monitored survival in each treatment using radio-telemetry during the non-breeding season (October through April) in 2013-2016. We used Burnham’s joint model within program MARK to compare survival of radio-tagged bobwhites among treatment groups. We analyzed data collected from a hand-held global positioning system used to delineate paths during creation to compute implementation cost. Hunter satisfaction was assessed using a pre- and post-hunt survey. Optimization will be used to determine which treatment achieves the greatest utility under current management objectives. Results of this research will provide managers information to make informed decisions about the implementation of hunting paths under various management scenarios

Additional Evidence Against Radio-handicapping of Northern Bobwhites

The validity of radio-telemetry to produce reliable information (e.g., survival estimates) has recently been challenged. Radio-telemetry is a widely used technique in studies of numerous species, therefore, concerns regarding potential bias in these estimates warrant further investigation. As such, and as part of a larger study, we investigated 3 aspects of potential radio-bias: 1) variation in survival distributions among treatment (newly radio-tagged) and control (previously radio-tagged) groups; 2) proportion of trapped animals censored during the traditional 7-day censor period; and 3) ramifications to cause-specific mortality through estimation of harvest rate. Kaplan-Meier survival, based on 30-day post trapping, was similar between treatment (n = 901) and control (n = 293) bobwhites for all but 1 of 8 trapping sessions during 2000-2004. In this case, treatment bobwhites (0.970, SE = 0.015) had higher survival than control birds (0.878, SE = 0.042). We determined the effect of censoring relative to sample size was inconsequential for our analysis because the proportion of bobwhites (18 out of 1,350; 0.013) meeting the criteria for censoring, i.e., dying during the first 7 days, was minimal. Censoring of these data influenced survival estimates by an average of only 0.016 (SE = 0.004; range: 0.00 - 0.04). We evaluated harvest rate by comparing first year recovery rates of banded verses radio-tagged birds during thirteen hunting seasons occurring between 1992 and 2005. Annual recovery rate was not different (P \u3c 0.05) for banded birds and radio-tagged birds where harvest averaged 6.68% (range 3.3 - 11.7) and 6.65% (range 3.4 - 11.1), respectively. These findings are consistent with previous research demonstrating that radio-telemetry can provide reliable demographic information. However, we recommend that future researchers test for these potential effects among their data before making biological inferences

Behavioral State-Specific Northern Bobwhite Chick Resource Selection

Determining resource selection rates for all life stages of a species is critical to enable a holistic management approach that focuses on bolstering populations across all life stages. Moreover, tying these selection rates to specific life history needs (e.g., foraging, roosting, and loafing) can provide valuable information to guide management practices. Northern bobwhite (Colinus virginianus; hereafter, bobwhite), a gallinaceous species of North America, has experienced steady population declines throughout much of its range over the last 50 years. Although the species has been well studied, chick ecology is still relatively unknown. We studied bobwhite chick resource selection on a private property in Brunswick County, North Carolina, USA to better understand daily and within home range selection. The site was managed intensively for bobwhite using prescribed fire, seasonal mowing and disking, mesomammal control, and supplemental feeding. We radio-tagged 156 chicks 11–15 days of age from 29 unique broods and collected location data for nocturnal roost sites, daily movement tracks, and diurnal use sites during a 2-year span. We had selection models for 3 behaviors: roosting, foraging, and general movements within home range (third-order). All models were mixed-effects conditional logistic regression models under a Bayesian framework. We determined foraging behavior using a straightness index for daily track segments; more tortuous segments were designated as foraging locations. Upland pine stands (burned and unburned) were selected for foraging and roosting. Chicks were more likely to select areas closer to feedlines for roosting, foraging, and diurnal habitat; however, selection of these areas decreased as birds grew older. Chicks avoided fallow fields and hardwood drains or Carolina bays as roost site locations yet selected them as foraging habitat. Roosting birds avoided fallow fields as roost sites and instead selected areas adjacent to them. Probability of use for diurnal and roosting habitat decreased as distance to fallow fields increased. Our study results shed light on how circadian habitat use can vary and illustrate that one specific land cover may not provide ideal diurnal and nocturnal habitat for bobwhite chicks. The results also reinforce the need to provide resources that meet diurnal and nocturnal requirements within biologically reasonable distances from each other

Using First Passage Time Analysis to Identify Foraging Patterns of the Northern Bobwhite

Patterns in movement data can reveal important information relating environmental variables to behavioral mechanisms. First passage time analysis (hereafter; FPT) can be used to quantify the spatial and temporal variation in movements by identifying areas of restricted search behavior based on measuring residence time in an area. It is applicable in studies of foraging ecology and habitat selection because it can empirically quantify behavioral decisions without any a priori assumptions of habitat availability. Furthermore, FPT analysis is simple to implement and interpret; however, the technique has yet to be applied to the northern bobwhite (Colinus virginianus, hereafter bobwhite) because telemetry locations in short (e.g., 30 min) successive time intervals are needed. Our primary objective was to better understand patterns in foraging behavior of bobwhites as it relates to habitat use and improve management. Our secondary objective was to test the efficiency of using FPT analysis on telemetry data collected at different time intervals. Bobwhites were captured during the fall of 2013 and 2014 on a private plantation in South Carolina and fitted with very high frequency (VHF) transmitters (n = 143 and n = 148, respectively). We located coveys at 1 hour (2013) and 30 (2014) minute time intervals during daylight. Bobwhites concentrated their searching efforts to a few hours pre-dusk. Search efforts were proximal to supplemental food sources, with some intra-seasonal variation. Advances in global positioning system (GPS) technology will likely increase opportunities for collecting fine-scale movement data for bobwhites. Understanding techniques such as FPT analysis will enhance our knowledge of northern bobwhite ecology and management

The Effect of Age-At-Release on Survival of Adoptive Parent-Reared Bobwhite Chicks

Translocation of wild northern bobwhites (Colinus virginianus) to restore local populations is a viable conservation tool under some scenarios; however, the supply of wild bobwhites is limited. Bobwhites can be artificially propagated, as an alternative to translocation, using methods that mimic natural brood-rearing. The parent-rearing adoptive process (PRAP) uses wild-strain bobwhite adults to brood and foster newly hatched wild-strain chicks in outdoor aviaries that emulate a natural environment. Adoptive parent-reared bobwhites have higher survival rates than artificially-reared bobwhites but only a single age-of-release (i.e., 6-weeks) has been tested. We tested the effect of age-at-release (3, 6, and 9-weeks) on adoptive parent-reared chicks released on the same date in Hanna Hammock of Tall Timbers Research Station. All chicks were marked with patagial wing tags and a subset of the group received radio transmitters. The 3-week-olds (n = 25) received suture-style transmitters and 6-week-olds (n = 30) and 9-week-olds (n = 30) received necklace-style transmitters. Our adoptive parent-reared chicks had low survival rates over 3 months post-release, the 9-week age group had the highest overall survival rates which could portend that increased physiological development may aid in increasing the survivability of adoptive parent-reared bobwhites. The low survival rates across all 3 age classes calls into question the efficacy of the PRAP as a bobwhite restoration method. Our results do suggest that additional modifications to release age (\u3e 9-weeks) should be explored along with further modifications to the PRAP. Additional modifications include incorporating predator avoidance training, altering release dates, and changing nutritional regimes. These results should caution the bobwhite community to remain suspect when deriving conclusions about the PRAP until all process modifications have been fully evaluated by scientific research

Northern Bobwhite Demographic and Population Response Following an Intensive Habitat Modification to an Agricultural Landscape

Northern Bobwhite (Colinus virginianus) populations have been declining throughout most of their endemic range due to numerous factors (e.g., increased urbanization, predators); however, changing land-use practices have proved most detrimental to bobwhites. In parts of the southeastern USA, small-scale farming has been replaced by large-scale center-pivot irrigated fields and this has exacerbated habitat loss. Despite these trends, bobwhite populations in the Southeast have remained stable or increased on many areas employing intensive habitat management regimes, substantiating the importance of appropriate habitat management for long-term bobwhite persistence. In effort to reverse one such decline, we intensively modified a center-pivot, agriculture dominated landscape to benefit bobwhites by creating new habitat and improving existing habitat. Techniques utilized to modify this landscape were: establishment of linear habitats (field borders and buffer strips); planting longleaf pines; and management of existing habitat via prescribed burning and timber management. During 1998-2001, we monitored bobwhite (n = 498) demographics and population response following annual habitat restoration and management using radio-telemetry and fall abundance estimation (i.e., covey call-counts). Average survival during over-winter (0.4698, SE = 0.0721), breeding (0.3561, SE = 0 .0667) and annual (0.1673, SE = 0.0411) time-periods were higher than those reported for other agriculture studies and similar to those of intensively managed, “plantation” habitats. Bobwhite coveys and broods used newly developed longleaf pine, linear habitats (e.g. field borders/hedgerows), and managed woodlands. Further, nest site selection was commonly associated with these novel habitat types. As a result of the positive demographic response to habitat modification, bobwhite abundance also improved during the study. Consequently, we surmised that modification of agricultural landscapes may improve habitat quality and quantity for bobwhites and subsequently help to increase demographic rates and bobwhite abundance

Hunter-Covey Interactions Using Pointing Bird Dogs

Hunting northern bobwhites (Colinus virginianus) with pointing dogs is a long-standing tradition in the Southeastern United States. Despite this rich hunting legacy, a paucity of empirical, behavioral information exists on the interaction between bobwhite coveys, pointing dogs and humans. As such, the efficiency of using pointing dogs to locate bobwhite coveys or an individual covey’s behavioral response to hunting is poorly understood. During 2013 – 2015, we conducted hunts (n = 192) by mode of foot on Tall Timbers Research Station (TTRS, ~1,570 ha) in Leon County, Florida and horseback on a private property (2,023 ha) in Georgetown County, South Carolina. We captured bobwhites (n = 741) and fitted them with activity-switch enabled radio-transmitters, and we tracked coveys prior to, during and after hunts. We used 2 types of global positioning system (GPS) units to collect route data from dogs and hunters (via horseback or foot). We recorded encounter information (e.g., behavior, encounter type such as covey point or wild flush) in the field using a pre-configured application on an iPad and linked spatial data using a geographic information system (i.e., ArcGIS). On average, 52% of all radio-tagged coveys were available (within a dog’s scent radius) during a hunt of which 73% were detected by pointing bird dogs. The overall probability of observing a covey on a hunt was 38% suggesting that most coveys within a hunting course go undetected. Vegetation density did not appear to be an impediment to bobwhite mobility or an important factor in detection of coveys by bird dogs. The potential reduction or manipulation of existing habitats may help to constrain where bobwhite coveys can escape to and covertly improve hunting efficiency. Furthermore, our results imply that a relatively high bobwhite density is required for sportsman to frequently encounter bobwhite coveys during a hunt