231,127 research outputs found
Home, dirty home: lesser kestrels prefer to breed in previously used nest sites
No full textPopulations of cavity nesting species are typically limited by the availability of suitable nesting sites. However, the factors driving the choice of a suitable nest sites are poorly investigated. For instance, individuals may prefer breeding in previously unused nest sites, that may host less parasites, or in previously used nest sites, which may provide cues of successful breeding attempt. We performed a simple nestbox choice experiment to assess whether breeding individuals prefer dirty and already used nestboxes vs. newly deployed ones. The study was carried out in Matera, which hosts the larger Italian colony of lesser kestrel. All nestboxes used for this experiment were provided within the framework of LIFE project.
Before lesser kestrel arrival we crated 40 nestbox dyads, pairing 40 used nest box with 40 new ones with nestbox entrances positioned side by side in order to force the choice. To disentangle the effect of nest substrate from the appearance of the nestbox we randomly exchanged entrance panels (old and new) and nest substrate (organic material from previous nesting attempts vs. sand and gravel). We than assessed which nestbox belonging to each dyads was first occupied. At the end of the egg laying period, 38 of 40 dyads had at least one nestbox occupied. Among these, in 36 cases birds selected the nestboxes with the old substrate. The adjoining nestboxes with new substrate was occupied by a second pair just in 4 case. The experiment suggests a strong preference of lesser kestrel for nest sites already used during previous breeding seasons: despite their possible higher parasitic load, used breeding sites may provide cues of previous breeding attempt. Under a management point of view, this result suggests that conservation actions based on installation of nestboxes can benefit from the translocation of substrates from used nestbox to newly deployed ones
Vertical variation in flight activity of the lesser short-tailed bat in podocarp and beech forests, Central North Island, New Zealand
No full textDesigning robust monitoring programmes for cryptic species is particularly difficult. Not detecting a species does not necessarily mean that it is absent from the sampling area. A conclusion of absence made in error can lead to misguided inferences about distribution, colonisation and local extinction estimates, which in turn affects where and how conservation actions are undertaken. It is therefore important to investigate monitoring techniques that reduce the non-detection rate of cryptic species. As habitat complexity plays an important role in the activity of bats within a forest, it was hypothesised that the amount of vegetative ‘clutter’ present at different heights within two different forest types affected the flight activity of lesser short-tailed bats (Mystacina tuberculata). This could affect detection of the species within different forest structures. To compare bat activity at three heights – top (22.0–25.0 m), middle (10.0–12.0 m) and bottom (1.5–2.0 m) – within a podocarp and a beech forest we used automatic bat monitors during January to March 2005. The number of bat passes was recorded at each height at two study areas within each forest and compared between forest types. The forest structure was described using the Recce method and vegetative cover estimated within the three height tiers sampled for bat activity. Within both forest types, the middle-level bat detectors logged the greatest amount of activity. However, differences between the forest types were most pronounced closer to the ground, where a high amount of activity was detected within the beech forest, and very little within the podocarp forest. This suggests that flight activity of lesser short-tailed bats may be affected by the level of vegetative clutter found at different heights within a forest. When designing monitoring programmes for lesser short-tailed bats, it is recommended that consideration be given to the forest structure and how this may affect detection of bat activity
Reconstructing the exhumation history of the Lesser Himalaya, Northern, India, from a multi-technique provenance study of the foreland basin Siwalik Group.
No full textThis research presents the first multitechnique provenance study of the Siwalik Group in the Himalayan foreland basin in India, using the Jawalamukhi section, magnetostratigraphically dated at 13–5 Ma. Combined with provenance data from a Dharamsala Formation sedimentary section (21–13 Ma) located close by, it forms the longest temporally continuous record of Himalayan erosion in the Indian foreland basin. Sandstone petrography and heavy mineral analysis, conglomerate clast composition, Ar‐Ar dating of detrital white micas, and Sm‐Nd analyses on siltstones, conglomerate matrix and conglomerate clasts was undertaken to determine (1) shifts in source region through time and (2) changes in detrital lag times related to exhumation rates in the hinterland, together interpreted in the light of thrusting events. We interpret the data to show a slow down in exhumation rate of the Higher Himalaya by 16–17 Ma, after which time the locus of thrusting propagated south of the Main Central Thrust, and erosion of the low grade Haimanta Formation to the south became significant. The nonmetamorphosed Inner Lesser Himalaya breached its Haimanta cover by 9 Ma with the metamorphosed Inner Lesser Himalaya (Lesser Himalayan Crystalline Series) exhuming to surface by 6 Ma. This event caused sufficient disruption to established drainage patterns that all Higher Himalayan material was diverted from this location at this time
Upper crustal structure of an active volcano from refraction/reflection tomography, Montserrat, Lesser Antilles
No full textTo better understand the volcanic phenomena acting on Montserrat, the SEA-CALIPSO seis-mic experiment (Seismic Experiment with Airgun-source – Caribbean Andesitic Lava Island Precision Seismo-geodetic Observatory) was conducted in 2007 December with the aim of imaging the upper crust and the magmatic system feeding the active Soufri ?ere Hills Volcano. The 3-D survey covered an area of about 50
× 40 km and involved the deployment of 247 land stations and ocean-bottom seismometers (OBSs). A subset of the data, recorded by four OBSs and four land stations on a southeast to northwest line, has been analysed, and traveltimes have been inverted to obtain a 2-D seismic velocity model through the island. Inverted phases include crustal and sediment P waves and wide-angle reflections. The resulting velocity model reveals the presence of a high velocity body (3.5–5.5 km s?1 ) beneath the island, with highest velocities beneath the Soufri ?ere and Centre Hills, cor responding primarily to the cores of these volcanic edifices, built of a pile of andesite lava domes and subsequent intrusions. In the off-shore region, velocities in the surficial sediment layer vary from 1.5 to 3.0 km s?1 , consistent with a mainly calcareous and volcaniclastic composition. A wide-angle reflector is observed at a depth of ?1200 m below the seabed, and appears to deepen beneath the island. The upper crust beneath this reflector has velocities of 4.0–6.0 km s?1 and is infer red to cor respond to plutonic and hypabyssal rocks and sedimentary material of the old arc. The high velocity region beneath the island, extends into the crust to a depth of at least 5 km, and is believed to be caused by an intrusive complex, possibly of intermediate composition. A low velocity zone, as would be expected in the presence of an active magma chamber, was not observed perhaps due to the limited resolution beneath ?5 km depth. Our results so far provide the first wide-angle seismic constraints on the upper crustal structure of the island to a depth of 10 km, and will help understanding the processes that drive volcanism at Montserrat and other island arc volcanoes
More than 30 years of studies and conservation on lesser kestrel in Europe: where do we will go from there?
No full textOur ecological knowledge on the lesser kestrel is today wide, but the reasons for the research are many and
varied, leading to an unequal representation and coverage of the issues addressed, which in addition can be
more or less directly related to the conservation of the species. For these reasons, I decided to review all the
work done so far, to identify the strengths and weaknesses of research applied to the conservation of this
species
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Comparative breeding ecology of Lesser Sandhill Cranes (Grus canadensis canadensis) and Siberian cranes (G. leucogeranus) in Eastern Siberia
No full textPopulations of Lesser Sandhill Crane (Grus canadensis canadensis) have been
increasing during the last decades in Eastern Siberia, an area historically known as
breeding grounds of endangered Siberian Cranes (G. leucogeranus). Significant overlap
in niche dimensions between the two species may occur and could lead to competition
between them. Therefore, this study of comparative breeding ecology of common
Lesser Sandhill Cranes and endangered Siberian Cranes was performed.
From late May to early August 2000, I studied Lesser Sandhill and Siberian cranes
within a 30,000-ha part of Kytalyk Resource Reserve in the Republic of Sakha (Yakutia),
Russia. My main objective was to compare dispersion patterns and resource use of
breeding Lesser Sandhill and Siberian cranes in areas of distribution overlap.
Lesser Sandhill Cranes used moderate-wet (polygon) areas as their nest sites and
main foraging areas, where terrestrial foods were scattered. In contrast, Siberian Cranes
were nesting and foraging on low-basin wet areas, where aquatic foods were concentrated and dominant. Inter-nest distances were less for heterospecific cranes than
for conspecific cranes, and more territorial behavior was projected toward conspecifics
than toward heterospecifics. Lesser Sandhill Cranes were more mobile and used
moderate-wet (polygon) areas more than Siberian Cranes; however, both species spent
similar time foraging and being alert.
The two crane species used different vegetation types for nesting and foraging,
had different time-activity budgets, and used different resources in the Siberian tundra.
While the population of Lesser Sandhill Cranes in the study area has the potential to
increase, both species may simultaneously share the same geographic area due to
differences in ecological requirements
Reproductive decisions in the lesser black-backed gull larus fuscus and their effects on reproductive success
No full textThe effect of several fundamental reproductive 'decisions' upon reproductive success were examined over a three year period at a large, inland gullery in the Pennines. Variations in reproductive parameters in relation to timing of breeding and reproductive success were compared among years. Determinants of the degree of hatching asynchrony were identified. Eggs from two years were taken for yolk lipid analysis, using gas chromatography. Variation in micronutrient content of eggs within clutches and between years was assessed in relation to egg size and yolk size, in order to examine resource allocation decisions of individuals. Timing of breeding of individuals was experimentally manipulated through the exchange of whole clutches of eggs between early and late laying birds, whilst controlling for variation in clutch size and egg-size, in order to assess whether the seasonal decrease in reproductive success was best explained by a decrease in food supply or differences in quality among parents. I experimentally manipulated the within-brood mass hierarchy of gulls, whilst controlling for variation in both chick quality and parental quality, in order to assess the effect of hatching asynchrony per se on chick growth and survival, and whether parents optimized the degree of hatching asynchrony with respect to the prevailing food supply. Brood size was experimentally reduced in order to assess the costs and benefits of the production of supernumary young. This was acheived by comparison of chick growth, feather development and chick survival of unmanipulated three-chick broods with broods where either the a-chick or the c- chick had been removed. I present a general discussion of the results within the context of life-history theory and a model for the evolution of hatching asynchrony in the lesser black-backed gul
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
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