Silver gull breeding at two colonies in the Sydney-Wollongong regio, Australia

1992 ◽  
Vol 19 (4) ◽  
pp. 429 ◽  
Author(s):  
GC Smith ◽  
N Carlile

Silver gulls have increased in abundance in Sydney-Wollongong this century. Both the number of colonies and their sizes have grown. The largest colony of 43 000-50000 pairs is on Big I., off Wollongong. Breeding was compared at this colony with that at a satellite colony on artificial structures in Rozelle Bay, Sydney Harbour. Breeding occurred from July to February at Big I., a lengthening of the season since the 1960s. At Rozelle Bay, breeding occurred almost all year round. Egg and clutch size varied within and between years at Big I. First-eggs of clutches, laid during the first breeding peak, were significantly larger than those laid later in each breeding season. The size of third-eggs in clutches differed between years. It is proposed that these disparities were a result of differences in food availability between years. Clutch sizes were significantly larger during the first breeding peak than later clutches of each season. Clutch size was larger at Rozelle Bay. Variation in clutch size was linked to quality of individuals and food availability. Breeding success at colonies was low, indicating that carrying capacities have been reached.

1993 ◽  
Vol 71 (11) ◽  
pp. 2141-2146 ◽  
Author(s):  
Christoph Steeger ◽  
Ronald C. Ydenberg

We studied the breeding performance of ospreys (Pandion haliaetus) in southeastern British Columbia from 1987 to 1990. Clutch size, brood size, and the number of young fledged per nest all declined significantly as clutch initiation date was delayed. The quality of later born young as measured by growth rate and the number of fault bars in rectrices did not seem to be reduced. Behavioural observations of the flight-hunting performance of six focal males demonstrated that food availability did not decline in the course of the nestling period. Clutch initiation of some osprey pairs was naturally delayed when their nests were occupied by Canada geese (Branta canadensis). Nest occupation delayed clutch initiation by 9.4 days on average, and reduced clutch size by 0.2 eggs. Osprey pairs possessing an alternate nest were not delayed by the presence of geese in their primary nest, and did not reduce clutch size, suggesting that the clutch size reduction was a direct response to the delay, rather than to the presence, of geese. The results do not support the reduced food availability or reduced breeding commitment hypotheses for seasonal clutch size decline. The data conform to the predictions of the hypothesis that the optimal clutch size is set by a trade-off between the declining reproductive value of later hatched nestlings and the delay required to be able to enlarge the clutch.


2000 ◽  
Vol 27 (6) ◽  
pp. 583 ◽  
Author(s):  
M. Giese ◽  
S. D. Goldsworthy ◽  
R. Gales ◽  
N. Brothers ◽  
J. Hamill

The long-term effects of oiling on the breeding success of rehabilitated oiled little penguins (Eudyptula minor) were examined over two consecutive breeding seasons following the Iron Baron oil spill in 1995. The commencement of egg laying was delayed among rehabilitated oiled penguins compared with non-oiled birds during the 1995/96 breeding season. During that season, hatching success (number of eggs hatched from those laid) was no different in nests containing rehabilitated oiled penguins than in those containing non-oiled birds, but overall egg success (number of pre-fledging chicks from the number of eggs laid) was significantly lower among rehabilitated oiled birds. This effect was predominant in nests containing a rehabilitated oiled female, where the probability of successfully fledging any chicks was 22% lower than in nests containing a non-oiled female. During the 1996/97 breeding season, there was no significant difference between either the hatching or egg success of rehabilitated oiled penguins and non-oiled birds. In both seasons, the pre-fledging masses of chicks from rehabilitated oiled penguins were significantly lower than those from non-oiled birds. The chicks of rehabilitated oiled penguins were therefore expected to have lower survival than chicks raised by non-oiled parents. Results indicate that oiling not only reduced the number of chicks raised by rehabilitated oiled penguins in the short term, but also decreased the quality of young produced for at least two seasons following the spill.


The Auk ◽  
2019 ◽  
Vol 136 (4) ◽  
Author(s):  
Facundo A Gandoy ◽  
Kaspar Delhey ◽  
David W Winkler ◽  
Giselle Mangini ◽  
Juan I Areta

Abstract It is widely assumed that colonizing species thrive because they lack natural enemies in their new range, increasing their survival and reproductive success. Barn Swallows (Hirundo rustica) started to breed in South America around 1980 and since then have dramatically increased their population size and geographic range, in stark contrast to the decline of the source population in North America. The reasons behind the growth of the South American population are unknown. However, because this species had never bred in this area in recorded times, the lack of natural predators, parasites, or pathogens could lead to higher breeding success, as predicted by the enemy release hypothesis. Here, we test whether breeding success is higher in the newly colonized range than in the native range to test the enemy release hypothesis. We studied the breeding biology of South American Barn Swallows quantifying 7 breeding parameters: clutch size, overall breeding success, offspring mortality by predation and ectoparasites, number of fledglings per breeding attempt, number of breeding attempts per breeding season, and total number of fledglings produced per pair per breeding season. Additionally, we compared these parameters with published information from North American populations using meta-analyses. We found that, while clutch size did not differ between North and South American populations, the southern population overall had lower breeding success, with higher mortality from predation and ectoparasites. An egg laid in South America was 2.6 times more likely to fail than one laid in North America, which resulted on average in 1.1 fewer fledglings per pair per breeding season for the South American breeding population. These results, demonstrating lower breeding success in a newly colonized range, do not support the enemy release hypothesis, and indicate that the growth of the South American Barn Swallow population is most likely caused by other demographic factors.


1970 ◽  
Vol 11 (1) ◽  
Author(s):  
M. F. Jaman ◽  
N. Sahreen

Studies on the ecology and breeding biology of Chestnut-tailed Starling, Sturnus malabaricus (Gmelin) were carried out from June 1997 to July 1998 in Dhaka and Nilphamari districts. This bird mainly found in parties and small flocks on the upper canopy and leaf of the trees to feed on insects. Breeding season of this bird started from the early February and ended to last July. A total of 30 nests were studied those were found in 5 species of trees and in the ventilation of buildings in five study areas. The peak nesting period was in March. Both sexes took part in nest building, egg incubation, brooding and feeding of nestlings. The mean clutch size was 3 ± 0.63 eggs. Out of 30 eggs belonged to 10 nests, 20 (66.67%) were hatched and the rest 10 (33.33%) were lost and infertile. The mean incubation period was 17 ± 1.3 days. Brood size varied from 1-3 nestlings. Out of 20 nestlings hatched, 10 (50%) were fledged successfully. The breeding success was 33.33% in relation to the number of eggs laid and 50% in relation to the nestlings hatched. The fledging period varied from 19 to 21 days. Key words: Ecology, breeding biology, Chestnut-tailed Starling, Sturnus malabaricus. Ecoprint Vol.11(1) 2004.


2019 ◽  
Author(s):  
Chem Int

Liquid effluents discharged by hospitals may contain chemical and biological contaminants whose main source is the different substances used for the treatment of patients. This type of rejection can present a sanitary potentially dangerous risk for human health and can provoke a strong degradation of diverse environmental compartments mainly water and soils. The present study focuses on the quality of the liquid effluents of Hassani Abdelkader’s hospital of Sidi Bel-Abbes (West of Algeria). The results reveal a significant chemical pollution (COD: 879 mgO2/L, BOD5: 850 mgO2/L, NH4+ : 47.9 mg/l, NO2- : 4.2 mg/l, NO3- : 56.8 mg/l with respect to WHO standard of 90 mgO2/L, 30 mgO2/L, 0.5 mg/l, 1 mg/l and 1 mg/l respectively). However, these effluents are biodegradable since the ratio COD/BOD5 do not exceeded the value of 2 in almost all samples. The presence of pathogen germs is put into evidence such as pseudomonas, the clostridium, the staphylococcus, the fecal coliforms and fecal streptococcus. These results show that the direct discharge of these effluents constitutes a major threat to human health and the environment.


1979 ◽  
Vol 10 (2-3) ◽  
pp. 171-190
Author(s):  
Pertti Lahermo ◽  
Jouko Parviainen

In this study the changes in the quality of groundwater are described on the basis of material collected at some groundwater extraction plants situated mainly in urban areas. The causes of the marked increase in the content of dissolved solids are evaluated from the 1960s onwards.


2021 ◽  
pp. 234763112110072
Author(s):  
Srinivasan Lakshminarayanan ◽  
N. J. Rao ◽  
G. K. Meghana

The introductory programming course, commonly known as CS1 and offered as a core course in the first year in all engineering programs in India, is unique because it can address higher cognitive levels, metacognition and some aspects of the affective domain. It can provide much needed transformative experiences to students coming from a system of school education that is dominantly performance-driven. Unfortunately, the CS1 course, as practiced in almost all engineering programs, is also performance-driven because of a variety of compulsions. This paper suggests that the inclusion of a course CS0 can bring about transformative learning that can potentially make a significant difference in the quality of learning in all subsequent engineering courses. The suggested instruction design of this course takes the advantage of the unique features of a course in programming. The proposed CS0 course uses “extreme apprenticeship” and “guided discovery” methods of instruction. The effectiveness of these instruction methods was established through the use of the thematic analysis, a well-known qualitative research method, and the associated coding of transformative learning experiences and instruction components.


Noise Mapping ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 248-264
Author(s):  
Rosa Maria Alsina Pagès ◽  
Francesc Alías ◽  
Patrizia Bellucci ◽  
Pier Paolo Cartolano ◽  
Ilaria Coppa ◽  
...  

AbstractThe COVID-19 pandemic was confirmed in Italy at the end of January 2020, when the first positive cases for the virus were identified. At the beginning of March, the virus had spread to all Italian regions and on 10 March 2020 the lockdown phase began, limiting the movement of people and prohibiting almost all commercial activities, businesses and non-essential industries. As a result, millions of people were forced to stay at home, causing a drastic drop in traffic volume, which significantly changed the acoustic environment and air quality of cities. On 4 May 2020, the lockdown was partially lifted and activities were progressively reopened. Therefore, traffic gradually started to increase and, consequently, the noise emitted by motor vehicles. This behaviour was confirmed by the data collected by the DYNAMAP system, an automatic platform developed within the LIFE DYNAMAP project, providing real time traffic noise maps in terms of sound pressure levels and impacts at receivers (people and dwellings exposed to noise level bands). In this paper traffic and non-traffic-related noise events in the cities of Rome and Milan from March to May 2020 are analysed and compared to the corresponding values in 2019 to evaluate the effects of the lockdown period.


Author(s):  
Mihai Marian BORZAN ◽  
Dana PUSTA ◽  
Liviu BOGDAN ◽  
Alexandra TABARAN ◽  
Attila MATE ◽  
...  

Abstract: The research aims to compare some qualitative characteristics of purebred Tsigaia lambs and Tsigaia crossed with Blanc du Massif Central lambs. The criteria assessed were: chemical composition of purebred and Tsigaia crossed meat, the live body weight, the slaughtering performance, the weight of different carcass cut. For almost all criteria chosen the crossed individuals registered better results.


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