A Survey for Federally Listed Grassland Birds at First Nations Reserves

We surveyed native and non-native grassland for federally listed grassland bird species at Reserves and/or Treaty Land Entitlements (TLE) belonging to five First Nations in the prairie ecozone of Canada. Ferruginous Hawk (Buteo regalis – of special concern), Loggerhead Shrike (Lanius ludovicianus – threatened), and Long-billed Curlew (Numenius americanus – of special concern) were observed at five of 335, three of 361, and five of 329 survey points within their respective geographic ranges. Sprague’s Pipit (Anthus spragueii – threatened) was observed at 69 of 361 survey points and accounted for 84% of sites with listed birds. Estimates of proportions of native and non-native grassland within 400 m of survey points indicated that Sprague’s Pipit preferred native grassland. Despite special effort, the Burrowing Owl (Athene culicularia – endangered) was not observed, although a nest from a previous year was encountered. We recorded the greatest number of species and individuals on reserves located in mixed and moist-mixed grasslands that contained large portions of native grassland. In many instances, field assessments revealed unsuitable habitat at sites that remote-sensing data classified as suitable

Experimental measurements of hull pressures on fast displacement catamarans during motions in long-crested head-seas

Piezoresistive pressure transducers have been used to measure the pressure variations at six points on a catamaran hull moving in regular, long-crested, head-seas. Preliminary results demonstrate the feasibility of this experimental approach although a more refined experimental procedure may be required to obtain greater accuracy in the pressure measurements.The pressure measurements were carried out for one demihull spacing at two speeds in calm water and also in regular waves of differing wave periods. The mean pressures from both calm water and regular wave tests are presented along with the RMS variation from the mean during the tests in regular waves

Off-road sampling reveals a different grassland bird community than roadside sampling: implications for survey design and estimates to guide conservation

Grassland bird species continue to decline steeply across North America. Road-based surveys such as the North American Breeding Bird Survey (BBS) are often used to estimate trends and population sizes and to build species distribution models for grassland birds, although roadside survey counts may introduce bias in estimates because of differences in habitats along roadsides and in off-road surveys. We tested for differences in land cover composition and in the avian community on 21 roadside-based survey routes and in an equal number of adjacent off-road walking routes in the grasslands of southern Alberta, Canada. Off-road routes (n = 225 point counts) had more native grassland and short shrubs and less fallow land and road area than the roadside routes (n = 225 point counts). Consequently, 17 of the 39 bird species differed between the two route types in frequency of occurrence and relative abundance, measured using an indicator species analysis. Six species, including five obligate grassland species, were more prevalent at off-road sites; they included four species listed under the Canadian federal Species At Risk Act or listed by the Committee on the Status of Endangered Wildlife in Canada: Sprague's Pipit (Anthus spragueii), Baird's Sparrow (Ammodramus bairdii), the Chestnut-collared Longspur (Calcarius ornatus), and McCown's Longspur (Rhynchophanes mccownii). The six species were as much as four times more abundant on off-road sites. Species more prevalent along roadside routes included common species and those typical of farmland and other human-modified habitats, e.g., the European Starling (Sturnus vulgaris), the Black-billed Magpie (Pica hudsonia), and the House Sparrow (Passer domesticus). Differences in avian community composition between roadside and off-road surveys suggest that the use of BBS data when generating population estimates or distribution models may overestimate certain common species and underestimate others of conservation concern. Our results highlight the need to develop appropriate corrections for bias in estimates derived from roadside sampling, and the need to design surveys that sample bird communities across a more representative cross-section of the landscape, both near and far from roads

Iron Age and Romano-British Occupation at Craven Arms Enclosure B, Shropshire: Investigations in 2013

The investigations at Craven Arms B exposed the north-western corner and a length of the northern ditches for a square enclosure, associated with external activity which spanned approximately 200 years. A double-ditched enclosure, external oven and V-shaped ditch for a timber stockade are interpreted as representing the first phase of activity, dating to late prehistoric times. During the first century AD the outer enclosure ditch was recut, and subsequent activity during the first to second centuries was evidenced by infill of the enclosure ditch, two corn-drying ovens, two possible timber structures, a ditch and a pit. The alignment and regularity of these features indicate a planned element to the site. Activity continued in the second to third centuries with a remodelling of the outer enclosure ditch, gullies indicating a fence line (possibly a parallel enclosure) and compacted surfaces around the entrance, other ditch features and decommissioning of the ovens and structures. The site appears to have been abandoned in the third century, with evidence for possible flooding interspersed with archaeological features across much of the site. Post-medieval activity consisted of two different types of land drain, indicating that water management on the site has been a recurring theme over the centuries

Influence of vegetation on the nocturnal foraging behaviors and vertebrate prey capture by endangered Burrowing Owls

Restrictions in technology have limited past habitat selection studies for many species to the home-range level, as a finer-scale understanding was often not possible. Consequently, these studies may not identify the true mechanism driving habitat selection patterns, which may influence how such results are applied in conservation. We used GPS dataloggers with digital video recorders to identify foraging modes and locations in which endangered Burrowing Owls (Athene cunicularia) captured prey. We measured the coarse and fine-scale characteristics of vegetation at locations in which owls searched for, versus where they caught, vertebrate prey. Most prey items were caught using hover-hunting. Burrowing Owls searched for, and caught, vertebrate prey in all cover types, but were more likely to kill prey in areas with sparse and less dense vegetative cover. Management strategies designed to increase Burrowing Owl foraging success in the Canadian prairies should try to ensure a mosaic of vegetation heights across cover types

Experimental measurements of the seakeeping characteristics of fast displacement catamarans in long-crested head-seas

The report describes an experimental investigation into the seakeeping properties of catamarans. Three geometrically similar hull forms were tested covering a range of Length:Displacement ratio from 7.4 to 9.5. The hulls are of round bilge transom stern form and are based on the NPL round bilge series. A number of hull configurations, including monohull and two catamaran demihull spacings, were tested at three Froude numbers (F subscript n = 0.2, 0.53, 0.8) and over a range of wavelengths. Long-crested head-seas were used for all experiments. Measurements of heave, pitch, vertical acceleration at two stations and added resistance in waves were made. Response functions have been calculated from both regular and irregular wave experiments