scholarly journals Population Studies on the Southern Black-Backed Gull

2021 ◽  
Author(s):  
◽  
Robin Alexander Fordham
Keyword(s):  
Breeding Success ◽  
Food Supply ◽  
Population Studies ◽  
Ecological Studies ◽  
Seasonal Fluctuations ◽  
Age Composition ◽  
Feeding Sites ◽  
Larus Dominicanus ◽  
The Social ◽  
Present Distribution

<p>An account is given of ecological studies on the Southern Black-backed Gull Larus dominicanus Licht in which attention is directed to the structure and balance of the Wellington population. This population is large; in the 1963-64 season more than 5,600 pairs were breeding in the study area, and the peak non-breeding season population in 1964 exceeded 12,000 birds. Its growth has been closely associated with the increase of the human population, and the present distribution and dispersal of gulls is strongly influenced by the distribution of " artificial" feeding sites such as refuse tips and meatworks. The population is composed of breeding colonies, night roosting flocks and daily communal flocks which are inter-related by the social activities and dispersal of the birds. Thus the population is more or less integrated, rather than simply comprising discrete geographic units. Seasonal fluctuations in size and age composition of communal flocks are discussed. Breeding success varies between colonies. It is affected by mammalian predation in some, and by drowning in others, while the largest colonies are comparatively safe for breeding birds. The rapid growth of the whole population in the last five to 10 years appears to have some influence on nesting density, clutch size, spread of laying and overall breeding success. In recent years production of young has been twice that required to maintain the population which has grown at the rate of not less than 7.2% annually. Mortality of banded gulls inside and outside the colony is described and the influence of several factors on chick mortality examined. The principal factor limiting the population appears to be the food supply in relation to the number of birds. When numbers increase and the food supply diminishes, major regulation of the population is apparently achieved in the colony by predation (but not cannibalism) of young by adults. Dispersal of banded gulls from the Wellington colonies is very restricted.</p>

scholarly journals Population Studies on the Southern Black-Backed Gull

2021 ◽  
Author(s):  
◽  
Robin Alexander Fordham
Keyword(s):  
Breeding Success ◽  
Food Supply ◽  
Population Studies ◽  
Ecological Studies ◽  
Seasonal Fluctuations ◽  
Age Composition ◽  
Feeding Sites ◽  
Larus Dominicanus ◽  
The Social ◽  
Present Distribution

<p>An account is given of ecological studies on the Southern Black-backed Gull Larus dominicanus Licht in which attention is directed to the structure and balance of the Wellington population. This population is large; in the 1963-64 season more than 5,600 pairs were breeding in the study area, and the peak non-breeding season population in 1964 exceeded 12,000 birds. Its growth has been closely associated with the increase of the human population, and the present distribution and dispersal of gulls is strongly influenced by the distribution of " artificial" feeding sites such as refuse tips and meatworks. The population is composed of breeding colonies, night roosting flocks and daily communal flocks which are inter-related by the social activities and dispersal of the birds. Thus the population is more or less integrated, rather than simply comprising discrete geographic units. Seasonal fluctuations in size and age composition of communal flocks are discussed. Breeding success varies between colonies. It is affected by mammalian predation in some, and by drowning in others, while the largest colonies are comparatively safe for breeding birds. The rapid growth of the whole population in the last five to 10 years appears to have some influence on nesting density, clutch size, spread of laying and overall breeding success. In recent years production of young has been twice that required to maintain the population which has grown at the rate of not less than 7.2% annually. Mortality of banded gulls inside and outside the colony is described and the influence of several factors on chick mortality examined. The principal factor limiting the population appears to be the food supply in relation to the number of birds. When numbers increase and the food supply diminishes, major regulation of the population is apparently achieved in the colony by predation (but not cannibalism) of young by adults. Dispersal of banded gulls from the Wellington colonies is very restricted.</p>

scholarly journals Addressing sustainable food management in hotels: proposing a framework and examining hotel groups

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
María Eugenia Ruiz Molina ◽  
Sergio Belda-Miquel ◽  
Anni Hytti ◽  
Irene Gil-Saura
Keyword(s):  
Food Supply ◽  
Sustainability Assessment ◽  
Corporate Sustainability ◽  
Sustainable Food ◽  
Content Type ◽  
Food Supply Chains ◽  
Food Management ◽  
The Social ◽  
Social Environmental ◽  
Comprehensive Framework

Purpose Sustainable food practices have been recognised as a key issue in efforts to improve and report sustainable tourism practices, given the importance of the social, environmental and economic impacts of the food industry throughout its entire chain of production – from farm to fork. From this standpoint, the aim of the present paper is to propose a comprehensive framework for reporting or making decisions concerning sustainable food management in hotels, taking into account the various facets of the food supply chain.Design/methodology/approach Several dimensions are proposed for dealing with sustainable food management, involving all aspects of food supply chains that may be relevant for hotel decision-making. Furthermore, some key criteria for creating and using indicators of different types (qualitative and quantitative) to address these various dimensions of sustainable food management are suggested. Subsequently, the proposed framework is validated with the sustainability criteria and indicators provided by the top eight hotel groups, according to the 2019 SAM Annual Corporate Sustainability Assessment.Findings Hotels neglect a number of aspects of sustainable food management identified in the framework. The quality and the quantity of the information provided by hotels are limited.Practical implications There is a need to improve sustainability in food management in the hotels under analysis in several areas. A comprehensive framework such as that proposed in this paper may be of great value in seeking to remedy this situation. It may also assist users of hotel services and communities in making more informed decisions.Originality/value The proposed framework may be beneficial in advancing academic debate towards a more embracing and relevant understanding of sustainable food management in hotels and on the indicators required in this regard.

scholarly journals Late Summer and Fall Nesting in the Acorn Woodpecker and Other North American Terrestrial Birds

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 334-350
Author(s):  
Walter D. Koenig ◽  
Justyn T. Stahl
Keyword(s):  
Global Warming ◽  
North American ◽  
Breeding Success ◽  
Population Studies ◽  
Late Summer ◽  
Substantial Fraction ◽  
Melanerpes Formicivorus ◽  
Summer Temperatures ◽  
Total Productivity ◽  
Acorn Woodpeckers

Abstract Acorn Woodpeckers (Melanerpes formicivorus) at Hastings Reservation in central coastal California exhibit a bimodal peak in annual breeding activity. One peak occurs in spring during which the majority of breeding takes place, while a second is centered in late August as the new acorn crop matures. These latter nests are mostly initiated in late summer but often do not fledge until at least late September and are thus referred to here as ‘fall’ nests. Fall nests occur in about one-third of all years, taking place when the acorn crop is large and summer temperatures are relatively high. Fledglings from fall nests constitute 4.3% of the population's total productivity and survive and recruit to the population at levels comparable to spring fledglings. Fall nesting is less likely in groups in which either the male or female breeding adults have undergone a change from the prior year, but groups are otherwise indistinguishable. Ecologically, fall nesting is closely tied to the acorn crop and thus to breeding success in the following, rather than the prior, spring. Among North American terrestrial birds in general, fall breeding has been reported in 16% of all species and is significantly more common among residents and colonially nesting species, in which the frequency exceeds 25%. Furthermore, fall nesting is likely to have been underreported in the literature. Thus, this phenomenon is at least an irregular part of the breeding biology of a substantial fraction of North American birds and should be considered a possibility in population studies of temperate-zone species. This is especially true given that fall nesting is likely to increase as global warming takes place.

Flight Activity and Displacement in the Rutherglen Bug Nysius Vinitor (Hemiptera: Lygaeidae).

1973 ◽  
Vol 21 (3) ◽  
pp. 413 ◽  
Author(s):  
M Kehat ◽  
M Wyndham
Keyword(s):  
Host Plants ◽  
Population Studies ◽  
Weather Conditions ◽  
Flight Activity ◽  
Migratory Behavior ◽  
Seasonal Fluctuations ◽  
Large Numbers ◽  
Seasonal Migrations ◽  
Population Source ◽  
Short Time

Population studies for determining seasonal fluctuations of N. vinitor indicated that the appearance or disappearance of populations within a short time can be attributed mainly to its highly migratory behavior. N. vinitor always migrated when host plants dried up, and sometimes also when they were still green. Continuous quantitative records of flight activity, made near the population source, showed that the seasonal migrations of N. vintor closely reflected its population curve. As populations increased and declined throughout the season, migrants were produced continuously, resulting in a fairly smooth succession of departing individuals which became particularly obvious when large numbers suddenly discharged which occurred when special weather conditions caused sudden excessive flights.

Association of a Burrower Bug (Heteroptera: Cydnidae) with Aflatoxin Contamination of Peanut Kernels

2004 ◽  
Vol 39 (1) ◽  
pp. 71-83 ◽  
Author(s):  
Jay W. Chapin ◽  
Joe W. Dorner ◽  
James S. Thomas
Keyword(s):  
Arachis Hypogaea ◽  
Food Supply ◽  
Aflatoxin Contamination ◽  
Feeding Sites ◽  
Arachis Hypogaea L ◽  
Aflatoxin Concentration

Aflatoxin contamination of peanut kernels, Arachis hypogaea L., was associated with feeding by a burrower bug, Pangaeus bilineatus (Say). Kernel samples were divided into three grade categories: total sound mature kernels (TSMK), other kernels (OK), and damaged kernels (DK); and each of these grade categories was subdivided based on evidence of burrower bug feeding. Within TSMK, 100% of detectable aflatoxin contamination was associated with burrower bug kernel feeding, and kernels with feeding sites had a significantly higher concentration of aflatoxin than kernels without feeding sites (7.5 vs 0.0 ppb). Within the OK grade category, differences in aflatoxin contamination were not significant due to the inability to conclusively examine these kernels for feeding sites. Within the DK grade category, aflatoxin concentration was significantly higher in kernels with feeding sites than in kernels without observable feeding sites (286.5 vs 0.4 ppb), and 99.9% of contamination was associated with burrower bug feeding. Across all grade categories, aflatoxin levels were 65X higher in kernels with observable burrower bug feeding, and 98% of all aflatoxin contamination was associated with burrower bug feeding. The DK grade category had the highest concentration of aflatoxin and accounted for 45% of total contamination. Burrower bug-induced aflatoxin contamination of the TSMK grade category is particularly significant because this source would be most difficult to remove from the food supply. Contamination of the DK category is also economically significant because this grade component is specifically examined for Aspergillus at the buying point, and growers are severely penalized for detection.

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