Echolocation Calls and Patterns of Hunting and Habitiat Use of Bats (Microchiroptera) from Chillagoe, North Queensland

1982 ◽  
Vol 30 (3) ◽  
pp. 417 ◽  
Author(s):  
MB Fenton
Keyword(s):  
North America ◽  
Habitat Use ◽  
Echolocation Calls ◽  
Flying Insects ◽  
Over Time

The search phase echolocation calls of 12 species of microchiropteran bats were studied in the vicinity of Chillagoe. Different species were recognizable by their calls, and differences in patterns of change in frequency over time. frequencies, and call durations were useful in identifying bats in the field. Some species (Nyctophilus bifax, Hipposideros diadema, and Rhinolophus megaphyllus) made short flights from perches to intercept flying insects. while others flew continuously while hunting, reacting to targets at short (c. 1m; Eptesicus pumilus, Nycticeius balstoni) or long (over 2 m; Chalinolobus nigrogriseus, Taphozous georgiunus, the two molossids) range. By sampling echolocation calls it was possible to obtain some measure of habitat use by different species. The results are compared to data from sites in North America and Africa.

scholarly journals Is there an imbalance in the supply and demand for universal accessibility knowledge? Twenty years of UAIS papers viewed through the lens of WCAG

2021 ◽  
Author(s):  
Frode Eika Sandnes
Keyword(s):  
Latin America ◽  
North America ◽  
Supply And Demand ◽  
Research Focus ◽  
Universal Accessibility ◽  
Geographical Regions ◽  
Research Profile ◽  
The Impact ◽  
Over Time

AbstractPurpose: Some universal accessibility practitioners have voiced that they experience a mismatch in the research focus and the need for knowledge within specialized problem domains. This study thus set out to identify the balance of research into the main areas of accessibility, the impact of this research, and how the research profile varies over time and across geographical regions. Method: All UAIS papers indexed in Scopus were analysed using bibliometric methods. The WCAG taxonomy of accessibility was used for the analysis, namely perceivable, operable, and understandable. Results: The results confirm the expectation that research into visual impairment has received more attention than papers addressing operable and understandable. Although papers focussing on understandable made up the smallest group, papers in this group attracted more citations. Funded research attracted fewer citations than research without funding. The breakdown of research efforts appears consistent over time and across different geographical regions. Researchers in Europe and North America have been active throughout the last two decades, while Southeast Asia, Latin America, and Middle East became active in during the last five years. There is also seemingly a growing trend of out-of-scope papers. Conclusions: Based on the findings, several recommendations are proposed to the UAIS editorial board.

scholarly journals Mechanisms of Seasonal Soil Moisture Drought Onset and Termination in the Southern Great Plains

2019 ◽  
Vol 20 (4) ◽  
pp. 751-771 ◽  
Author(s):  
Richard Seager ◽  
Jennifer Nakamura ◽  
Mingfang Ting
Keyword(s):  
Soil Moisture ◽  
North America ◽  
Great Plains ◽  
Land Surface ◽  
Tropical Pacific ◽  
Moisture Change ◽  
Southern Plains ◽  
Southern Great Plains ◽  
Continental Scale ◽  
Over Time

AbstractMechanisms of drought onset and termination are examined across North America with a focus on the southern Plains using data from land surface models and regional and global reanalyses for 1979–2017. Continental-scale analysis of covarying patterns reveals a tight coupling between soil moisture change over time and intervening precipitation anomalies. The southern Great Plains are a geographic center of patterns of hydrologic change. Drying is induced by atmospheric wave trains that span the Pacific and North America and place northerly flow anomalies above the southern Plains. In the southern Plains winter is least likely, and fall most likely, for drought onset and spring is least likely, and fall or summer most likely, for drought termination. Southern Plains soil moisture itself, which integrates precipitation over time, has a clear relationship to tropical Pacific sea surface temperature (SST) anomalies with cold conditions favoring dry soils. Soil moisture change, however, though clearly driven by precipitation, has a weaker relation to SSTs and a strong relation to internal atmospheric variability. Little evidence is found of connection of drought onset and termination to driving by temperature anomalies. An analysis of particular drought onsets and terminations on the seasonal time scale reveals commonalities in terms of circulation and moisture transport anomalies over the southern Plains but a variety of ways in which these are connected into the large-scale atmosphere and ocean state. Some onsets are likely to be quite predictable due to forcing by cold tropical Pacific SSTs (e.g., fall 2010). Other onsets and all terminations are likely not predictable in terms of ocean conditions.

scholarly journals Breeding ecology and habitat use of North America’s rarest Ardeidae: the Reddish Egret Egretta rufescens

2018 ◽  
Vol 13 (2) ◽  
Author(s):  
Lianne M. Koczur ◽  
Bart M. Ballard ◽  
M. Clay Green ◽  
David G. Hewitt ◽  
Scott E. Henke
Keyword(s):  
North America ◽  
Habitat Use ◽  
Breeding Ecology ◽  
Egretta Rufescens

Epistemological Importance and Fluted Points: An Observation

1989 ◽  
Vol 10 (1) ◽  
pp. 63-66
Author(s):  
Shawn D. Haley
Keyword(s):  
North America ◽  
North American ◽  
Projectile Points ◽  
Native North American ◽  
Fluted Points ◽  
Over Time

The earliest cultures of North America produced exquisitely made fluted projectile points. Over time, projectile points became progressively more crude in form and workmanship. A common explanation for this apparent regression is that native North American stone workers “lost the art of fine flint knapping.” This hypothesis is questioned and an alternative offered. It is suggested that regression had not occurred. Rather, there had been a shift in epistemological importance away from projectile points into more relevant areas for those more recent cultures. Points simply were no longer important to them.

scholarly journals Does vegetation change over 28 years affect habitat use and reproductive success?

The Auk ◽  
2019 ◽  
Vol 137 (1) ◽  
Author(s):  
Karolina Fierro-Calderón ◽  
Thomas E Martin
Keyword(s):  
Reproductive Success ◽  
Habitat Use ◽  
Nest Survival ◽  
Selection Function ◽  
Patch Use ◽  
Fitness Consequences ◽  
Long Term Changes ◽  
Changes Over Time ◽  
Over Time

Abstract Individuals should prefer and use habitats that confer high fitness, but habitat use is not always adaptive. Vegetation in natural landscapes changes gradually and the ability of species to adaptively adjust their habitat use to long-term changes is largely unstudied. We studied nest patch and territory use over 28 yr in Orange-crowned Warblers (Oreothlypis celata) in a system that has undergone natural long-term changes in vegetation. Abundance of maple (Acer grandidentatum), its preferred nesting habitat, gradually declined from 1987 to 2015. We examined whether habitat use and its fitness consequences changed as the availability of preferred habitat decreased. We used resource selection function models to determine changes over time in the probability of using a nest patch given available patches, and the probability of using a territory given available territories. We estimated nest survival to evaluate changes over time in the fitness consequences of nest patch use. We also compared habitat use (nest patch and territory) and fitness (nest survival) between areas with naturally reduced abundance of maple and experimentally increased abundance of maple (fenced areas). Nest patch use depended on maple abundance and did not change drastically across 28 yr, even though the availability of preferred maple patches decreased over time. In contrast, nest survival tended to decrease over time. We did not see differences in nest patch use and nest survival between unfenced and fenced areas, unlike territory use, which increased with the abundance of maple in fenced areas and decreased in unfenced areas. Our study depicts one example of relatively unchanged habitat use in the face of decreased availability of preferred vegetation across years, with a resulting decrease in reproductive success. Investigating changes in habitat use and fitness consequences for animals exposed to long-term habitat change is necessary to understand adaptive behavioral responses.

Feeding Habitats of Nesting Wading Birds: Spatial Use and Social Influences

The Auk ◽  
1983 ◽  
Vol 100 (4) ◽  
pp. 960-970 ◽  
Author(s):  
R. Michael Erwin
Keyword(s):  
Habitat Use ◽  
Spatial Scales ◽  
Close Association ◽  
Habitat Patch ◽  
Wading Birds ◽  
Feeding Habitat ◽  
Snowy Egret ◽  
Colony Site ◽  
The One ◽  
Over Time

Abstract In an effort to relate social interactions to feeding-habitat use, I observed six species of wading birds near a major colony site in coastal North Carolina. Three spatial scales of habitat use were considered: the general orientation to and from the colony (coarsest level), the habitat "patch," and (at the finest level) the microhabitat. Departure-arrival directions of Great Egrets (Casmerodius albus), Snowy Egrets (Egretta thula), Cattle Egrets (Bubulcus ibis), Little Blue Herons (Egretta caerulea), Tricolored Herons (Egretta tricolor), and Glossy Ibises (Plegadis falcinellus) were monitored at the colony site to document coarse patterns of feeding-habitat use. Added to these data were observations made at five different wetland sites to monitor between-habitat and within-habitat patterns for the five aquatic-feeding species. The results indicated a broad and variable use of feeding habitat over time. At the coarsest scale (i.e. orientation at the colony), diffuse patterns, influenced little by either inter- or intraspecific social interaction, were found for all species. At the next level (habitat "patch"), only one of five wetland sites was relatively consistent in attracting feeding birds, and its use increased from May to June. Few groups were seen at four of the five sites. At the one "attractive" site, the within-habitat patterns again were spatially variable over time, except for those of the abundant Snowy Egret, whose microhabitat preference was fairly consistent. Glossy Ibises and Snowy Egrets frequently formed mixed-species groups, Little Blue Herons were the least social, and Great Egrets and Tricolored Herons generally occurred in groups of less than 10 birds but rarely in groups larger than 30. The close association between Snowy Egrets and Glossy Ibises appeared to be based on a "beater-follower" relationship, wherein the probing, nonvisually feeding ibises make prey more available to the followers. In the study area, local enhancement appeared to play a more important role than did any "information-sharing" at the colony.

The genesis of international mass migration

2018 ◽  
Author(s):  
Eric Richards
Keyword(s):  
North America ◽  
Structural Changes ◽  
British Isles ◽  
Scottish Highlands ◽  
Isle Of Man ◽  
Mass Migration ◽  
Large Numbers ◽  
Starting Point ◽  
The Common ◽  
Over Time

Very large numbers of people began to depart the British Isles for the New Worlds after about 1770. This was a pioneering movement, a rehearsal for modern international migration. This book contends that emigration history is not seamless, that it contains large shifts over time and place, and that the modern scale and velocity of mobility have very particular historical roots. The Isle of Man is an ideal starting point in the quest for the engines and mechanisms of emigration, and a particular version of the widespread surge in British emigration in the 1820s. West Sussex was much closer to the centres of the expansionary economy in the new age. North America was the earliest and the greatest theatre of oceanic emigration in which the methods of mass migration were pioneered. Landlocked Shropshire experienced some of the earliest phases of British industrialisation, notably in the Ironbridge/Coalbrookdale district, deep inland on the River Severn. The turmoil in the agrarian and demographic foundations of life reached across the British archipelago. In West Cork and North Tipperary, there was clear evidence of the great structural changes that shook the foundations of these rural societies. The book also discusses the sequences and effects of migration in Wales, Swaledale, Cornwall, Kent, London, and Scottish Highlands. It also deals with Ireland’s place in the more generic context of the origins of migration from the British Isles. The common historical understanding is that the pre-industrial population of the British Isles had been held back by Malthusian checks.

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