DDE and reproductive success in some Alberta common terns

1973 ◽  
Vol 51 (10) ◽  
pp. 1081-1086 ◽  
Author(s):  
Bruce Switzer ◽  
Victor Lewin ◽  
Fred H. Wolfe
Keyword(s):  
Reproductive Success ◽  
Breeding Population ◽  
Sterna Hirundo ◽  
Eggshell Thickness ◽  
Common Terns ◽  
Relationship Of ◽  
The Relationship

A study of the relationship of DDE to reproductive success of an inland breeding population of common terns. Sterna hirundo, had been carried out in 1969 and 1970 at Chip Lake, Alberta. Although a continuing decrease of DDE residues in eggs bad occurred, eggshell thickness remained unchanged. In addition, reproductive success markedly increased in 1970; however, the percentage of eggs suffering breakage did not change between years. Low correlations between DDE and eggshell thickness or weight in both years suggest that DDE is unrelated to these eggshell parameters, which in turn are not related to reproductive success in this population.

scholarly journals Floating rafts as breeding habitats for the Common tern, Sterna hirundo. Colonization patterns, abundance and reproductive success in Venice Lagoon

2018 ◽  
Vol 88 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Francesca Coccon ◽  
Stefano Borella ◽  
Nicola Simeoni ◽  
Stefano Malavasi
Keyword(s):  
Reproductive Success ◽  
Breeding Population ◽  
Venice Lagoon ◽  
Reproductive Period ◽  
Common Tern ◽  
Sterna Hirundo ◽  
Breeding Sites ◽  
Common Terns ◽  
Colonization Patterns ◽  
Floating Rafts

The Venice lagoon hosts the 15% of the entire Italian breeding population of Common terns, Sterna hirundo, highlighting the great value of the area for this species. However, in the last 25 years, a substantial decline of Common terns has been detected in the Lagoon, which culminated in 2008. The main causes of this negative trend were the loss of salt marsh habitats, where terns typically breed in the Venice lagoon. This was due to the increase in the mean sea level and the greater frequency of high tides during the reproductive period with consequent flooding of their breeding sites; competition with yellowlegged gulls (Larus michahellis), predation and human disturbance. As a preliminary experimental approach to counter the depletion of the species and favour its recovery, we performed a habitat loss compensation project by setting up four floating rafts (3x2m), covered by two different types of substrate (sandy and vegetal substrate). This was to function as an artificial nesting site safe from flooding, positioned in a protected internal wetland area of the Venice lagoon, Valle Averto (Sourthern Lagoon). We studied the colonization patterns of the rafts and the reproductive success of Common tern breeding pairs during the 2014 and 2015 breeding seasons. We also investigated those environmental and structural variables that could favour the use of the rafts and the nesting success of the species. In both years, the rafts were successfully colonized and used by terns for nesting. Our results also indicated higher temperature, lower rainfall and greater distance from the shore as the main habitat factors favouring the occurrence and the reproductive success of the breeding pairs, while a windrow of dead plants was indicated as the preferred substrate for covering rafts in order to make them more attractive. The results provided some suggestions for successful restoration plans to be developed in similar lagoon areas.

Shell thickness, DDE levels in eggs, and reproductive success in common terns (Sterna hirundo), in Alberta

1971 ◽  
Vol 49 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Bruce Switzer ◽  
Victor Lewin ◽  
Fred H. Wolfe
Keyword(s):  
Reproductive Success ◽  
Shell Thickness ◽  
Avian Species ◽  
Common Tern ◽  
Sterna Hirundo ◽  
Eggshell Thickness ◽  
Large Measure ◽  
Common Terns ◽  
The Common ◽  
Comprehensive Study

A comprehensive study of reproductive success of an isolated colony of common terns (Sterna hirundo) reveals that DDE, the principal chlorinated hydrocarbon insecticide found in the terns, cannot be correlated to eggshell thickness. The low reproductive success observed was attributed in large measure to disappearance of eggs and nest abandonment, responsible for 76% of the failures, while cracked or broken eggs accounted for only 16%. It is suggested that the direct correlation of DDE to eggshell thickness, implicated in the reproductive failure of other avian species, may be an oversimplification in the case of the common tern.

Comparative effects of mites and lice on the reproductive success of rock doves (Columba livia)

Parasitology ◽  
1995 ◽  
Vol 110 (2) ◽  
pp. 195-206 ◽  
Author(s):  
D. H. Clayton ◽  
D. M. Tompkins
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Growth Rates ◽  
Columba Livia ◽  
Nestling Growth ◽  
Adult Body Mass ◽  
Evolution Of Virulence ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

SUMMARYWe report experimental data comparing the effects of Mesostigmatid mites and Ischnoceran lice on the reproductive performance of a single group of captive rock doves (Columba livia). Several components of host reproductive success were compared for the two groups, including number of eggs laid, hatching success, nestling growth rates, fledging success, post-fledging body mass and survival. Adult body mass and survival were also compared. There was a dramatic difference in the effects of the mites and lice. The former drove host reproductive success to zero, mainly by agitating adults and causing them to incubate eggs less faithfully. Nestling growth rates and post-fledging survival were also significantly reduced by mites. Lice showed no effect on reproductive success whatsoever, even though the feather damage they cause is known to have energetic consequences (Booth, Clayton & Block, 1993). Neither parasite had a significant effect on adult birds. Although Ischnocera are found on most species of birds, our results for lice constitute the first experimental test of the impact of Ischnocera on avian reproductive success (preliminary report by Clayton & Tompkins, 1994). We discuss reasons for the different effects of mites and lice, including the relationship of horizontal (mites) and vertical (lice) transmission to the evolution of virulence.

scholarly journals BREEDING SUCCESS OF BUFF-NECKED IBIS (Theristicus caudatus) (PELECANIFORMES: THRESKIORNITHIDAE) IN ARAUCARIA PLATEAU, RIO GRANDE DO SUL, BRAZIL.

2019 ◽  
Vol 16 (31) ◽  
pp. 831-836
Author(s):  
Renata De Boni DAL CORNO ◽  
Gustavo Francisco AVER ◽  
Maria Virginia PETRY
Keyword(s):  
Reproductive Success ◽  
Environmental Changes ◽  
Reproductive Period ◽  
Hatching Rate ◽  
History Of ◽  
Different Populations ◽  
Group B ◽  
Relationship Of ◽  
The Relationship ◽  
Source Of Information

The life history of a species can be considered the main source of information about it, parameters such as incubation period, number of eggs and chicks, may represent the aptitude of individuals in relation to the environment, modified or not. Thus information from the reproductive success of a species allows evaluating the relationship of individuals to environmental changes. This study aimed to assess the reproductive success of three different populations of Buff-necked ibis, Theristicus caudatus, in Araucaria Plateau. The groups were followed in the reproductive season of 2011, three breeding which had environmental characteristics different from each other. We used three methods to determine the reproductive success: apparent success, hatching rate of eggs and protocol of Mayfield. In 600 hours of observation during the reproductive period, approximately 200 hours for each group, there was an average of 1.87 ± 0.74 eggs per nest. The apparent success and the protocol of Mayfield showed proportional differences between the groups. The environment where individuals were nesting in group B can be considered a compromise between the characteristics of other groups, with anthropogenic characteristics that draw predators away from nests and feeding areas, while feeding sites has reduced external influences.

Relationship of parasites (Trematoda: Spirorchidae) and their eggs to the occurrence of fibropapillomas in the green turtle (Chelonia mydas)

1995 ◽  
Vol 52 (S1) ◽  
pp. 84-89 ◽  
Author(s):  
Murray D. Dailey ◽  
Robert Morris
Keyword(s):  
Green Turtle ◽  
Sea Turtles ◽  
Chelonia Mydas ◽  
Breeding Population ◽  
Negative Effects ◽  
Tissue Sections ◽  
The Family ◽  
Relationship Of ◽  
The Relationship

The prevalence of green turtle (Chelonia mydas) fibropapillomatosis is increasing in Hawaii, raising the possibility of long-term negative effects on the breeding population. As the etiology of this disease is unknown, our objective was to determine if any relationship exists between fibropapillomas and trematode eggs from the family Spirorchidae, whose presence in tissue sections has been noted for years. A process for tumor digestion and egg extraction was developed and a total of 61 tumors of all sizes was examined to determine the total numbers of eggs present and the species of spirorchid involved. Twelve samples of normal turtle tissue were also examined. Eggs of one to three spirorchid species (Leardius learedi Price, 1934; Haplotrema dorsopora Dailey, Fast and Balazs, 1993; and Carettacola hawaiiensis Dailey, Fast and Balazs, 1991) were recovered from all tumors and nontumored tissues digested. Five turtles were injected with spirorchid eggs and observed for 12 months. New tumors developed on two of the turtles at noninjected sites. Although attempts to induce fibropapillomas through injection were not successful, the presence of spirorchid eggs in every tumor examined raises additional questions regarding the relationship between these parasites and fibropapillomas in sea turtles.

Sign in / Sign up

Export Citation Format

Share Document