Sex differences in behavior of beavers living in near-boreal lake habitat

1995 ◽  
Vol 73 (11) ◽  
pp. 2133-2143 ◽  
Author(s):  
Richard R. Buech
Keyword(s):  
Time Budget ◽  
Castor Canadensis ◽  
Late Summer ◽  
Open Water ◽  
Early Summer ◽  
Late Spring ◽  
Adult Males ◽  
Adult Females ◽  
Monogamous Species ◽  
Winter Food

Comparative studies of how female and male North American beavers (Castor canadensis) allocate time provide a basis for understanding their life history. I studied the behavior of beavers living in lake habitats of a near-boreal region to determine how animals of each sex allocated time during their active periods. Markov time-budget estimates revealed that over the open-water season, adult females and males spent 91 and 86%, respectively, of time during active periods feeding, traveling, and being in the lodge. Adult females spent most of their time feeding in late spring and summer. In late summer through fall, they spent more time provisioning, working on lodges, and constructing winter food caches. In contrast, adult males spent less time feeding and more time traveling, being in the lodge, and working on the lodge in late spring and early summer. As the season progressed, adult males traveled less and spent more time feeding and working on the lodge. Overall, the results suggest that there is a division of labor in this monogamous species. Adult females seemed to function primarily as providers of energy to kits. In contrast, adult males seemed to function primarily in protection and provisioning of kits, territory maintenance, and construction and maintenance of structures.

scholarly journals Fungal Decay of First-Crop and Main-Crop Figs

Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1657-1662 ◽  
Author(s):  
Mark A. Doster ◽  
Themis J. Michailides
Keyword(s):  
Aspergillus Niger ◽  
Alternaria Alternata ◽  
Late Summer ◽  
Early Summer ◽  
Late Spring ◽  
Fungal Decay ◽  
Main Crop ◽  
Low Levels ◽  
Serious Disease

Fig cultivars grown in California typically have two crops, although the first crop may be unimportant commercially. The first crop, also known as the breba crop, ripens in late spring and early summer, whereas the main or second crop ripens in late summer. For both cultivars studied, Conadria and Calimyrna, the first-crop figs typically are left in the orchard unharvested. First-crop figs had relatively high levels of fungal decay and tended to have more fungal decay than main-crop figs, especially Alternaria rot (caused by Alternaria alternata and Ulocladium atrum). At least 16 different Aspergillus spp. were found decaying first-crop figs. Fig smut, a serious disease caused by Aspergillus niger and related fungi, usually was present at approximately the same level in first-crop and main-crop figs. Aspergillus spp. known to produce the mycotoxins aflatoxin or ochratoxin were found decaying first-crop figs. Aflatoxin was detected in first-crop figs at low levels similar to those detected in the main-crop figs. Because the abundant spores produced on the first-crop figs can infect main-crop figs, the fungal decay of first-crop figs might result in higher levels of decay for main-crop figs.

scholarly journals Flowering Response of Bougainvillea Cultivars to Dikegulac

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 282-284 ◽  
Author(s):  
J.G. Norcini ◽  
J.H. Aldrich ◽  
J.M. McDowell
Keyword(s):  
Sodium Salt ◽  
Growth Habit ◽  
Foliar Spray ◽  
Late Summer ◽  
Early Summer ◽  
Late Spring ◽  
The Other ◽  
Spray Application ◽  
Flowering Response ◽  
Bougainvillea Glabra

Foliar spray application of dikegulac at 1600 mg·liter-1 during production of Bougainvillea glabra Choicy `Mauna Kea White', and Bougainvillea `Raspberry Ice', `Royal Purple', `Summer Snow', and `Temple Fire' in 4.5-liter hanging baskets (25.4 cm in diameter) was investigated in relation to flowering. The effect of foliar-applied dikegulac at 0, 400, 800, 1200, and 1600 mg·liter-1 on bracteole size of `Mauna Kea White' was also determined. Liners of `Temple Fire' pruned at transplanting (0 weeks) and sprayed with dikegulac at, 0 and 4 weeks had increased flowering and a slightly more compact, pendulous growth habit than plants that had only been pruned at 0 and 4 weeks. Dikegulac had little to no effect on flowering of the other cultivars. Under late-spring to early summer conditions (generally increasing temperatures), bracteole size of `Mauna Kea White' was reduced ≈25 % by 400 mg dikegulac/liter compared to nontreated plants; 800 to 1600 mg dikegulac/liter reduced bracteole size ≈37%. Under late-summer to mid-fall conditions when the weather was cooler and wetter, dikegulac had little to no effect on bracteole size; however, bracteoles of nontreated plants were ≈25% smaller than those of plants grown under the warmer and drier conditions of late spring to early summer. Chemical name used: sodium salt of 2,3:4,6-bis -O- (1-methylethylidene) -α-l-xylo- 2-hexulofuranosonic acid (dikegulac).

Seasonal changes in prevalence and intensity of Cosmocercoides dukae (Nematoda: Cosmocercoidea) in Deroceras laeve (Mollusca)

1987 ◽  
Vol 65 (7) ◽  
pp. 1662-1665 ◽  
Author(s):  
Daryl J. Vanderburgh ◽  
R. C. Anderson
Keyword(s):  
Natural Population ◽  
Seasonal Changes ◽  
Late Summer ◽  
Early Summer ◽  
Late Spring ◽  
New Host ◽  
Histological Sections ◽  
Arion Fasciatus ◽  
New Host Records

A natural population of Deroceras laeve was examined regularly for the presence of Cosmocercoides dukae (Holl, 1928) Travassos, 1931. Transmission of C. dukae in D. laeve occurred in late spring and early summer before adult slugs from the previous year died in July. Transmission to juvenile slugs (hatched from eggs laid in spring) continued in late summer and fall. Histological sections of slugs exposed experimentally to larvae of C. dukae revealed that larvae penetrate slug tissues. Arion fasciatus, Arion hortensis, and Zonitoides nitidus represent new host records for C. dukae.

Bears napping nearby: daybed selection by brown bears (Ursus arctos) in a human-dominated landscape

2018 ◽  
Vol 96 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Michaela Skuban ◽  
Slavomír Find’o ◽  
Matúš Kajba
Keyword(s):  
Ursus Arctos ◽  
Late Summer ◽  
Fruit Trees ◽  
Early Summer ◽  
Adult Males ◽  
Human Settlements ◽  
Activity Data ◽  
Brown Bears ◽  
North Central ◽  
Linear Mixed Effects

Daybeds are essential for the survival of brown bears (Ursus arctos L., 1758) and may represent a population-limiting resource in human-dominated landscapes. In this study, we demonstrate which land-cover types and bear characteristics affect daybed selection in north-central Slovakia. We used the positional and activity data of 21 bears acquired by GPS–GSM telemetry to identify 3864 daybeds. By use of K-select analysis and linear mixed-effects modelling, we explored how bears chose these places for their daytime resting. The most important drivers for daybed selection were the presence of dense regenerating forests and forest–shrubbery belts in farmland. Bears avoided resting in older forests without suitable undergrowth. Females selected daybeds differently depending on the presence of dependent cubs. During spring – early summer, females with cubs of the year avoided other bears by selecting more rugged terrain. These females also selected daybeds significantly closer to human settlements than adult males, possibly to avoid the risk of infanticide. In late summer – autumn, all bears selected daybeds closer to human settlements than in spring, probably because they were attracted by maize (Zea mays) fields and fruit trees. Many daybeds were located outside protected areas in farmland closer to people, which could increase bear–human conflicts.

scholarly journals Time budget patterns and complementary use of a Mediterranean wetland (Tonga, North-east Algeria) by migrant and resident waterbirds

2016 ◽  
Vol 86 (1) ◽  
pp. 55 ◽  
Author(s):  
Elafri Ali ◽  
Halassi Ismahan ◽  
Houhamdi Moussa
Keyword(s):  
Coastal Wetlands ◽  
Time Budget ◽  
Quantitative Description ◽  
Late Summer ◽  
Open Water ◽  
Feeding Time ◽  
Time Budgets ◽  
North East ◽  
Species Specific ◽  
Open Water Body

We carried out a quantitative description of the use of a Mediterranean wetland (Tonga, North-east Algeria) by 22 waterbirds species (11 residents and 11 Palaearctic migrants) during late summer-wintering period, also analyzing their species-specific diurnal time budgets and the main related features of the landscape. The analyses of similarity in time budgets across birds (Hierarchal Cluster Analysis) showed four clusters of species associated with four major activities: day time mostly feeding (11 species), sleeping (6), swimming (3) and resting (2). Residents (Herons and Rails) showed a higher feeding time when compared to migrants (diving ducks, Gulls and Cormorants). From late summer to winter the time budget activity change in migrants; in contrast residents behave uniformly among daytime and at the course of the season. The use of this natural wetland in a complementary way by a high number of waterbirds (residents and migrants), is principally promoted by the existing of numerous habitat types. We found that 3 main ecological units, open water body, mudflats, and flooded meadows were the most utilized as foraging habitats among grebes, rails, ducks, gulls, and herons. In contrast, floating-leafed vegetation, and tall emergent vegetation were the commonest habitat categories used in resting activities especially by cormorants and herons. Data on behaviour requirements of these waterbirds can be used for conservation and correct management of this and other Mediterranean coastal wetlands.

Foraging behaviour of beef cattle in the hilly terrain of a Mediterranean grassland

2012 ◽  
Vol 34 (2) ◽  
pp. 163 ◽  
Author(s):  
Z. Henkin ◽  
E. D. Ungar ◽  
A. Dolev
Keyword(s):  
Foraging Behaviour ◽  
Nutritive Value ◽  
Late Summer ◽  
Beef Cows ◽  
Early Morning ◽  
Grazing Pressure ◽  
Early Spring ◽  
Early Summer ◽  
Late Spring ◽  
Full Potential

The objective of this study was to determine the role of terrain in the foraging behaviour of beef cows grazing hilly Mediterranean grasslands. The study was conducted in eastern Galilee, Israel, during 2002 and 2003 on two similar 28-ha paddocks encompassing distinct terrain types in terms of slope and rock cover. The paddocks were continuously grazed by cows from mid winter (January–February) to autumn (September) at two different stocking rates (1.1 and 0.56 cows per ha). From early June to the end of September the cows were offered poultry litter ad libitum as a supplementary feed. The location and activity of cows were monitored with GPS collars during four periods in each year: early spring (February–March), late spring (April), early summer (June) and late summer (August). Herbage mass was measured at the beginning of each of these periods. During early and late spring, when the herbage mass and nutritive value of herbage were high, the cows spent 40–50% of the day grazing, with peaks in the morning and afternoon. In the dry, late summer period (August), grazing of the herbage was 20–22% of the day, occurring only in the early morning and late afternoon with sporadic bouts of grazing until midnight. In all periods the cows tended to prefer the flattest terrain sites. As the herbage mass declined to 1000–1500 kg ha–1, the exploitation of the pasture during grazing became increasingly similar among the different terrains. Even on relatively small paddocks, where grazing pressure was close to the full potential of the site, free-ranging cows tended to prefer less sloping and rocky sites. It is concluded that the grazing strategy of beef cows is determined by the interaction between terrain, the distribution of the herbage mass and the nutritive value of the herbage. As herbage mass declines during the growing season, the distribution of grazing becomes uniform and all terrain types are exploited.

scholarly journals Distribution, abundance and biology of ringed seals (Phoca hispida): an overview

1998 ◽  
Vol 1 ◽  
pp. 9 ◽  
Author(s):  
Randall R Reeves
Keyword(s):  
Polar Bear ◽  
Late Summer ◽  
Early Summer ◽  
Ringed Seal ◽  
Late Spring ◽  
Late Winter ◽  
Polar Cod ◽  
World Population ◽  
Phoca Hispida ◽  
Ringed Seals

The ringed seal (Phoca hispida) has a circumpolar Arctic distribution. Because of its great importance to northern communities and its role as the primary food of polar bears (Ursus maritimus) the ringed seal has been studied extensively in Canada, Alaska, Russia, Svalbard and Greenland as well as in the Baltic Sea and Karelian lakes. No clear-cut boundaries are known to separate ringed seal stocks in marine waters. Adult seals are thought to be relatively sedentary, but sub-adults sometimes disperse over long distances. Stable ice with good snow cover is considered the most productive habitat although production in pack ice has been little studied. Populations appear to be structured so that immature animals and young adults are consigned to sub-optimal habitat during the spring pupping and breeding season. Annual production in ringed seal populations, defined as thepup percentage in the total population after the late winter pupping season, is probably in the order of 18-24%. Most estimates of maximum sustainable yield are in the order of 7%.The world population of ringed seals is at least a few million. Methods of abundance estimation have included aerial surveys, dog searches and remote sensing of lairs and breathing holes, acoustic monitoring, correlation analysis by reference to sizes of polar bear populations, and inference from estimated energy requirements of bear populations. Aerial strip survey has been the method of choice for estimating seal densities over large areas. Adjustment factors to account for seals not hauled out at the time of the survey, for seals that dove ahead of the aircraft, and for seals on the ice within the surveyed strip but not detected by the observers, are required for estimates of absolute abundance.Male and female ringed seals are sexually mature by 5-7 years of age (earlier at Svalbard). Pupping usually occurs in March or early April and is followed by 5-7 weeks of lactation. Breeding takes place in mid to late May, and implantation is delayed for about 3 months. In at least some parts of their range, ringed seals feed mainly on schooling gadids from late autumn through early spring andon benthic crustaceans and polar cod (Boreogadus saida) from late spring through summer. Little feeding is done during the moult, which takes place in late spring and early summer. Pelagic crustaceans offshore and mysids inshore become important prey in late summer and early autumn in some areas. Ringed seals have several natural predators, the most important of which is the polar bear in most arctic regions. Arctic foxes (Alopex lagopus) kill a large percentage of pups in someareas.From a conservation perspective, the ringed seal appears to be secure. Levels of exploitation of arctic populations have usually been considered sustainable, except in the Okhotsk Sea. Large fluctuations in production of ringed seals in the Beaufort Sea and Amundsen Gulf are thought to be driven by natural variability in environmental conditions. While concern has been expressed about thepotential impacts of industrial activity and pollution on ringed seals, such impacts have been documented only in limited areas. Because of their ubiquitous occurrence and availability for sampling, ringed seals are good subjects for monitoring contaminant trends in Arctic marine food chains. 

Seasonal population dynamics of five species of intestinal helminths of the brook stickleback, Culaea inconstans

1983 ◽  
Vol 61 (9) ◽  
pp. 2129-2137 ◽  
Author(s):  
William F. Font
Keyword(s):  
Relative Density ◽  
Egg Production ◽  
Late Summer ◽  
Abundant Species ◽  
Early Summer ◽  
Late Spring ◽  
Culaea Inconstans ◽  
Brook Stickleback ◽  
Paratenic Hosts ◽  
Low Prevalence

Seasonal changes in populations of five species of enteric helminths that parasitize the brook stickleback (Culaea inconstans) were studied during a 14-month period in Wisconsin. The trematodes Bunodera eucaliae, B. luciopercae, and immature Halipegus sp., the acanthocephalan Neoechinorhynchus pungitius, and the larval cestode Proteocephalus sp. each displayed pronounced seasonal patterns of prevalence in Sioux Creek sticklebacks. Bunodera eucaliae, the most abundant species, infected sticklebacks in early summer. By late summer, most B. eucaliae had completed egg production and were expelled from their hosts. Some B. eucaliae overwintered in sticklebacks and completed development in late spring. In contrast, B. luciopercae displayed low prevalence in sticklebacks and produced eggs at the coldest period of the year. The relative density of N. pungitius increased throughout fall and winter. These acanthocephalans were most numerous and attained maximum development in late spring. Unencysted metacercariae of Halipegus sp. parasitized sticklebacks in midsummer but thereafter declined in relative density. Sticklebacks possibly acted as paratenic hosts for H. eccentricus which occur commonly in Rana pipiens and R. clamitans in Sioux Creek. A few sticklebacks harbored Proteocephalus sp. plerocercoids in midsummer but this parasite was virtually absent throughout the remainder of the year.

The effects of cutting frequency on yield of Hunter River lucerne grown at wide and close spacing in the Mediterranean climate of South Australia

1970 ◽  
Vol 10 (46) ◽  
pp. 582 ◽  
Author(s):  
GJ Leach
Keyword(s):  
South Australia ◽  
Late Summer ◽  
Ground Level ◽  
Early Summer ◽  
Late Spring ◽  
Sowing Time ◽  
Wide Spacing ◽  
Close Spacing ◽  
Number Of Stems ◽  
Autumn And Winter

Hunter River lucerne, sown in April, June, and August, was planted out at 60 cm X 60 cm or 20 cm X 20 cm spacings on a red brown earth soil. Plants were cut 2.5 cm above ground level every six to eight weeks (standard cutting), or twice as often (frequent cutting), for two years : the yield of dry matter and number of stems per plant were measured at each cut. Yields were smallest in late summer and autumn, and largest in late spring and early summer. Treatments generally had little effect on the seasonal growth rhythm. Frequent cutting nearly always decreased yields. The relative decrease was greatest when standard cut plants were growing most rapidly in late spring, and it was also greater with wide spacing than close spacing. Wide-spaced plants yielded more per plant, and less per unit area, than close-spaced plants, except in late summer. Sowing time influenced yield only until the middle of the first summer. Number of stems per plant, and the mean weight of each stem, were both smallest in autumn and winter, and largest in spring and early summer. Frequent cutting slightly, and increasingly, decreased stem numbers relative to the number present with standard cutting during the experiment. The number of stems per plant was largest, and generally increased throughout, at wide spacing, whereas at close spacing maximum stem numbers were attained in the establishment year. Weight per stem showed greater seasonal variation than numbers. Low winter yields and low yields with frequent cutting could both be largely attributed to the small stem weights. Some implications of these results for lucerne management, and breeding for yield improvement, are discussed.

Adrenal response in a wild Microtus population: seasonal aspects

1978 ◽  
Vol 56 (6) ◽  
pp. 1433-1440 ◽  
Author(s):  
Robert W. Seabloom ◽  
Stuart L. Iverson ◽  
Brian N. Turner
Keyword(s):  
Microtus Pennsylvanicus ◽  
Early Summer ◽  
Significant Decline ◽  
Adult Males ◽  
Free Living ◽  
Adult Females ◽  
Adrenal Response ◽  
Males And Females ◽  
Nonpregnant Adult ◽  
Seasonal Aspects

Adrenal response was determined during a 13-month period in a population of southern Manitoba meadow voles (Microtus pennsylvanicus) as a preliminary part of a study to determine the effects of chronic ionizing radiation on free-living mammals. Livetrapped voles were subjected to behavioral tests, killed, and their isolated adrenals superfused and stimulated with ACTH. Superfusates were assayed fluorometrically for corticosterone. Peaks of adrenal response occurred during spring in both adult males and females, followed by a significant decline into early summer. Subadult males exhibited a peak response in early summer. Corticosterone levels of adults were generally higher than those of juveniles in the same season. Levels of nonpregnant adult females were higher than those of pregnant voles. Observed differences over the annual cycle were attributed to the behavioral and hormonal states of various age and sexual components of the population.

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