Point counts are one of the most widely used and efficient approaches to survey land‐bird populations. A new approach to point‐count surveys involves the use of 2 observers, which allows the calculation of a detection probability for each bird species. Detection probabilities derived from 2 observers permit investigators to calculate a corrected abundance estimate that accounts for birds present but not detected. We evaluated 2 double‐observer point count approaches: the dependent‐observer approach and the independent‐observer approach. The dependent‐observer approach involves 2 observers recording data together on a single data sheet with one observer designated the primary observer and the other designated as the secondary observer. The primary observer verbally dictates the number of each species detected while the secondary observer records this information; the secondary observer also records birds that the primary observer did not detect. The independent‐observer approach involves 2 observers recording data independently on separate data sheets without verbal communication between observers. This study compares the detection probabilities and associated levels of precision generated by both double‐observer approaches to ascertain which technique generates data that are more accurate and more feasible to apply in the field. We conducted point counts at 137 point locations in northern West Virginia during the spring of 2000 and 2001 using both double‐observer approaches. We generated detection probabilities and abundances from data collected using both double‐observer approaches using program DOBSERV. The dependent‐observer approach resulted in higher observer‐specific and joint detection probabilities, as well as lower standard errors of detection probability across most cover types. Species‐specific detection probabilities were higher across all cover types under the dependent‐observer approach. Given the higher detection probabilities and associated precision combined with fewer logistical constraints, we suggest that the dependent‐observer approach be used when investigators are interested in surveying birds using point counts.

During 2001 and 2002, I surveyed three mountaintop mining / valley fill (MTMVF) complexes in southern West Virginia to determine vegetation characteristics important to nest site selection and to estimate nest success for Grasshopper Sparrow populations inhabiting these complexes. I also performed genetic analyses to assess overall population structure, mating system, parentage, kinship, and gender of individuals comprising these populations. A total of 415 grasshopper sparrows were captured and systematic searches of study plots produced 75 active nests. Nest survival for 2001-2002 breeding season (33%) is comparable to survival rates previously reported in the literature. Nest survival rates decreased with increased reclamation age suggesting that vegetation changes and the reduction of bare ground on available grasslands may negatively impact reproductive success. Habitat variables measured at nests and at fixed habitat plots suggest differences in several of the ground cover estimates. Percent green and grass height at 1 m were significantly lower at the nest plots while percent bare ground, percent litter at 1 and 5 m from the nest, grass height at 3 m, shrub stem density, and Robel pole indices at the nest were significantly higher at nest plots. Large reclaimed grassland habitats available on the MTMVF complexes appear sufficient to support breeding populations of grasshopper sparrows; however, habitat will become unsuitable as succession occurs. Genetic analyses suggest low but significant differentiation among mine complexes while the genetic structure of breeding assemblages within mine complexes appears to be homogeneous. The five microsatellite loci screened in this study are robust and appear to be effective in allocating parentage when neither parent is known. Using maximum likelihood methods, I was successful at assigning at least one parent to 80% of the offspring surveyed. The lack of extra-pair paternity within the grasshopper sparrow broods implies a socially and genetically monogamous mating system in this species.

We studied 3 mountaintop mining–valley fill (MTMVF) complexes in southern West Virginia, USA to examine grasshopper sparrow (Ammodramus savannarum pratensis) demographic response to different age classes of mine land reclamation. For 71 nests monitored during the 2001–2002 breeding seasons, overall nest success (36%) was within the range of nest success rates previously reported for this species, but it was highest on more recently reclaimed sites (56%). Nest density and clutch size did not differ (P > 0.30) among reclamation age classes, whereas number of fledglings was greater (P = 0.01) on more recently reclaimed sites. We measured vegetation variables at 70 nest subplots and at 96 systematic subplots to compare nest vegetation with vegetation available on the plots. We found that nests occurred in areas with more bare ground near the nest, greater vegetation height–density surrounding the nest site, lower grass height, and fewer woody stems, similar to previous studies. As postreclamation age increased, vegetation height–density and maximum grass height increased, and sericea (Lespedeza cuneata) became more dominant. Nest success declined with increasing vegetation height–density at the nest. The grasslands available on these reclaimed mine complexes are of sufficient quality to support breeding populations of grasshopper sparrows, but nest success decreased on the older reclaimed areas. Without active management, grasslands on reclaimed MTMVF mines become less suitable for nesting grasshopper sparrows about 10 years after reclamation. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Populations of North American river otters (Lontra canadensis) declined throughout large portions of the continent during the early 1900s due to habitat degradation and unregulated trapping. River otters had been extirpated in North Dakota (ND), but the Red River Valley has since been recolonized, with potential source populations including the neighboring states of Minnesota or South Dakota, or the Canadian province of Manitoba (MB). We genotyped 9 microsatellite loci in 121 samples to determine the source population of river otters in the Red River Valley of ND, as well as to assess population structure and diversity of river otters in central North America. Overall, genetic diversity was high, with an average observed heterozygosity of 0.58. Genetic differentiation was low (F ST < 0.05) between river otters in ND and those of Minnesota, suggesting that eastern ND was recolonized by river otters from Minnesota. River otters from MB were genetically distinct from all other sampled populations. Low genetic differentiation (F ST = 0.044) between South Dakota and Louisiana (LA) suggested that reintroductions using LA stock were successful. The genetic distinctiveness of river otters from different geographic regions should be considered when deciding on source populations for future translocations.

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