Effects of Sex, Age, and Habitat on Northern Bobwhite Spring Dispersal Patterns

Information on northern bobwhite (Colinus virginianus) dispersal patterns is crucial for implementing effective management strategies. Researchers have examined bobwhite dispersal, but information on how habitat affects dispersal patterns is lacking. We examined the effects of habitat, sex, and age on bobwhite spring dispersal patterns in a southern Georgia agricultural landscape during 2002-2003. Of 101 birds used in our analyses, 29.7% (4.6 SE) dispersed an average of 1,835m (194 SE). We fit 9 logistic regression models to predict bobwhite dispersal probability. The selected best model (Akaike weight [ω] = 0.58) included age, proportions of closed-canopy pine within winter home ranges (CCPN), and an age*CCPN interaction term. Adults with higher proportions of closed-canopy pine within their winter home range were more likely to disperse (ß = 0.18, 0.06 SE). Because of greater experience, adults may perceive habitat differently than juveniles, which could influence adult tendency to disperse. However, a significant portion of birds from both age classes will likely disperse every spring, regardless of habitat quality. Although dispersal may allow bobwhite populations to persist in fragmented landscapes, efforts to increase bobwhite populations at the local scale are hindered if emigration exceeds immigration. Therefore, it is important to consider landscape quality and management unit size when determining which areas are most likely to respond to management and the proper management strategy needed to achieve bobwhite population objectives

Summer Male Call Index Relative to Nesting Chronology and Autumn Density of the Northern Bobwhite

We studied breeding season male call counts and breeding behavior of the Northern Bobwhite (Colinus virginianus) to determine the relationship between male calling activity and nesting chronology. Additionally, we examined the relationship between breeding season call counts and fall population size. Standardized call count routes were conducted on 6 different sites located in southwest Georgia and north Florida during the breeding season months (1 Apr - 31 Sep) in 2001 and 2002. An information theoretic approach was used to evaluate a set of 7 candidate, linear-mixed models describing breeding season calling of bobwhite males. Of the candidate models, the model in which call counts depended on year and a quadratic effect of the number of incubating hens was the best approximating model, suggesting that the percentage of incubating hens had the greatest influence on activity of calling males. We also used multiple linear regression models to predict autumn northern bobwhite abundance from mean numbers of calling male bobwhites detected during the breeding season. Peaks in male calling activity occurring during June and July demonstrated a strong relationship (R2 = 0.987) with autumn population size, suggesting breeding season call counts were useful indices of autumn bobwhite abundance

Estimating Sample Sizes for Distance Sampling of Autumn Northern Bobwhite Calling Coveys

Point transect sampling of calling coveys has been advocated for estimating autumn abundance of northern bobwhite (Colinus virginianus; hereafter bobwhite). We conducted power analysis, over a range of expected bobwhite calling covey densities to determine levels of sampling required to obtain density estimates for calling coveys over a wide range of precision. We used distance/detection information for autumn bobwhite coveys from 701 observer-mornings on 39 farms in the Upper Coastal Plain of Georgia to construct a global detection function (Uniform with cosine adjustment) using Program DISTANCE. We used simulation models to determine the expected coefficient of variation (CV) on density in relation to number of points sampled. We generated 1,000 sets of random samples in increments of 10 at sample sizes of 10-1,000. At each sample size we generated the respective number of observations from a Poisson distribution with λ = 0.5-3.0 and computed the density and associated statistics using the global detection function. We report the mean CV on covey density at each sample size. As expected, the CV on density decreased with increasing sample size and expected number of detections per point. Assuming sufficient observations to estimate the detection function, a CV on density \u3c15% could be achieved with 50 points at densities with a mean detection of 1 covey/point or 20 points with a mean detection of 2 coveys/point. A mean CV \u3c10% required 100 points at 1 covey/point and 30 points at 2 coveys/point. These simulations demonstrate that distance-based autumn covey surveys can provide density estimates for calling coveys with reasonable precision given sufficient effort

Effect of Depth and Duration of Cooling on Death or Disability at Age 18 Months Among Neonates With Hypoxic-Ischemic Encephalopathy: A Randomized Clinical Trial

Importance Hypothermia for 72 hours at 33.5°C for neonatal hypoxic-ischemic encephalopathy reduces death or disability, but rates continue to be high. Objective To determine if cooling for 120 hours or to a temperature of 32.0°C reduces death or disability at age 18 months in infants with hypoxic-ischemic encephalopathy. Design, Setting, and Participants Randomized 2 × 2 factorial clinical trial in neonates (≥36 weeks’ gestation) with hypoxic-ischemic encephalopathy at 18 US centers in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network between October 2010 and January 2016. Interventions A total of 364 neonates were randomly assigned to 4 hypothermia groups: 33.5°C for 72 hours (n = 95), 32.0°C for 72 hours (n = 90), 33.5°C for 120 hours (n = 96), or 32.0°C for 120 hours (n = 83). Main Outcomes and Measures The primary outcome was death or moderate or severe disability at 18 to 22 months of age adjusted for center and level of encephalopathy. Severe disability included any of Bayley Scales of Infant Development III cognitive score less than 70, Gross Motor Function Classification System (GMFCS) level of 3 to 5, or blindness or hearing loss despite amplification. Moderate disability was defined as a cognitive score of 70 to 84 and either GMFCS level 2, active seizures, or hearing with amplification. Results The trial was stopped for safety and futility in November 2013 after 364 of the planned 726 infants were enrolled. Among 347 infants (95%) with primary outcome data (mean age at follow-up, 20.7 [SD, 3.5] months; 42% female), death or disability occurred in 56 of 176 (31.8%) cooled for 72 hours and 54 of 171 (31.6%) cooled for 120 hours (adjusted risk ratio, 0.92 [95% CI, 0.68-1.25]; adjusted absolute risk difference, −1.0% [95% CI, −10.2% to 8.1%]) and in 59 of 185 (31.9%) cooled to 33.5°C and 51 of 162 (31.5%) cooled to 32.0°C (adjusted risk ratio, 0.92 [95% CI, 0.68-1.26]; adjusted absolute risk difference, −3.1% [95% CI, −12.3% to 6.1%]). A significant interaction between longer and deeper cooling was observed (P = .048), with primary outcome rates of 29.3% at 33.5°C for 72 hours, 34.5% at 32.0°C for 72 hours, 34.4% at 33.5°C for 120 hours, and 28.2% at 32.0°C for 120 hours. Conclusions and Relevance Among term neonates with moderate or severe hypoxic-ischemic encephalopathy, cooling for longer than 72 hours, cooling to lower than 33.5°C, or both did not reduce death or moderate or severe disability at 18 months of age. However, the trial may be underpowered, and an interaction was found between longer and deeper cooling. These results support the current regimen of cooling for 72 hours at 33.5°C

Effect of Therapeutic Hypothermia Initiated After 6 Hours of Age on Death or Disability Among Newborns With Hypoxic-Ischemic Encephalopathy: A Randomized Clinical Trial

Importance: Hypothermia initiated at less than 6 hours after birth reduces death or disability for infants with hypoxic-ischemic encephalopathy at 36 weeks' or later gestation. To our knowledge, hypothermia trials have not been performed in infants presenting after 6 hours. Objective: To estimate the probability that hypothermia initiated at 6 to 24 hours after birth reduces the risk of death or disability at 18 months among infants with hypoxic-ischemic encephalopathy. Design, Setting, and Participants: A randomized clinical trial was conducted between April 2008 and June 2016 among infants at 36 weeks' or later gestation with moderate or severe hypoxic-ischemic encephalopathy enrolled at 6 to 24 hours after birth. Twenty-one US Neonatal Research Network centers participated. Bayesian analyses were prespecified given the anticipated limited sample size. Interventions: Targeted esophageal temperature was used in 168 infants. Eighty-three hypothermic infants were maintained at 33.5°C (acceptable range, 33°C-34°C) for 96 hours and then rewarmed. Eighty-five noncooled infants were maintained at 37.0°C (acceptable range, 36.5°C-37.3°C). Main Outcomes and Measures: The composite of death or disability (moderate or severe) at 18 to 22 months adjusted for level of encephalopathy and age at randomization. Results: Hypothermic and noncooled infants were term (mean [SD], 39 [2] and 39 [1] weeks' gestation, respectively), and 47 of 83 (57%) and 55 of 85 (65%) were male, respectively. Both groups were acidemic at birth, predominantly transferred to the treating center with moderate encephalopathy, and were randomized at a mean (SD) of 16 (5) and 15 (5) hours for hypothermic and noncooled groups, respectively. The primary outcome occurred in 19 of 78 hypothermic infants (24.4%) and 22 of 79 noncooled infants (27.9%) (absolute difference, 3.5%; 95% CI, -1% to 17%). Bayesian analysis using a neutral prior indicated a 76% posterior probability of reduced death or disability with hypothermia relative to the noncooled group (adjusted posterior risk ratio, 0.86; 95% credible interval, 0.58-1.29). The probability that death or disability in cooled infants was at least 1%, 2%, or 3% less than noncooled infants was 71%, 64%, and 56%, respectively. Conclusions and Relevance: Among term infants with hypoxic-ischemic encephalopathy, hypothermia initiated at 6 to 24 hours after birth compared with noncooling resulted in a 76% probability of any reduction in death or disability, and a 64% probability of at least 2% less death or disability at 18 to 22 months. Hypothermia initiated at 6 to 24 hours after birth may have benefit but there is uncertainty in its effectiveness

Effect of Depth and Duration of Cooling on Deaths in the NICU Among Neonates With Hypoxic Ischemic Encephalopathy: A Randomized Clinical Trial

Hypothermia at 33.5°C for 72 hours for neonatal hypoxic ischemic encephalopathy reduces death or disability to 44% to 55%; longer cooling and deeper cooling are neuroprotective in animal models

Evolutionary dynamics of emblematic Araucaria species (Araucariaceae) in New Caledonia:Nuclear and chloroplast markers suggest recent diversification, introgression, and a tight link between genetics and geography within species

BACKGROUND: New Caledonia harbours a highly diverse and endemic flora, and 13 (out of the 19 worldwide) species of Araucaria are endemic to this territory. Their phylogenetic relationships remain largely unresolved. Using nuclear microsatellites and chloroplast DNA sequencing, we focused on five closely related Araucaria species to investigate among-species relationships and the distribution of within-species genetic diversity across New Caledonia. RESULTS: The species could be clearly distinguished here, except A. montana and A. laubenfelsii that were not differentiated and, at most, form a genetic cline. Given their apparent morphological and ecological similarity, we suggested that these two species may be considered as a single evolutionary unit. We observed cases of nuclear admixture and incongruence between nuclear and chloroplast data, probably explained by introgression and shared ancestral polymorphism. Ancient hybridization was evidenced between A. biramulata and A. laubenfelsii in Mt Do, and is strongly suspected between A. biramulata and A. rulei in Mt Tonta. In both cases, extensive asymmetrical backcrossing eliminated the influence of one parent in the nuclear DNA composition. Shared ancestral polymorphism was also observed for cpDNA, suggesting that species diverged recently, have large effective sizes and/or that cpDNA experienced slow rates of molecular evolution. Within-species genetic structure was pronounced, probably because of low gene flow and significant inbreeding, and appeared clearly influenced by geography. This may be due to survival in distinct refugia during Quaternary climatic oscillations. CONCLUSIONS: The study species probably diverged recently and/or are characterized by a slow rate of cpDNA sequence evolution, and introgression is strongly suspected. Within-species genetic structure is tightly linked with geography. We underline the conservation implications of our results, and highlight several perspectives. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12862-014-0171-6) contains supplementary material, which is available to authorized users