scholarly journals LONG-TERM DYNAMICS OF THE CRESTED AUKLET AETHIA CRISTATELLA PALLAS,1769 POPULATION AND ITS BREEDING SUCCESS ON TALAN ISLAND (SEA OF OKHOTSK)

Author(s):  
A.V. Andreev ◽  
◽  
E.Yu. Golubova ◽  
Author(s):  
V. A. Zubakin ◽  
◽  
E. V. Zubakina ◽  
A. V. Klenova ◽  
D. S. Vodolazova ◽  
...  

The crested auklet is a medium-sized planktivorous seabird of the Alcidae family with complex social behavior, one of the interesting forms of which is the formation of club pairs in addition to existing breeding pairs. The occurrence of club pairs in this species was studied on the Talan Island (Sea of Okhotsk) in 1988-1989, when the colony was in a good condition, and in 2008-2015, when its population decreased several times. The research showed that the proportion of individuals with club partners is higher in a high-population period (35 %) and lower in a low-population period (18 %); the differences, however, are not significant. In both study periods, from 73% (1988-1989) to 80 % (2008-2015) individuals were consistent in following the chosen strategy of forming or not forming club pairs for at least two seasons. The presence of club pairs seems to facilitate the change of mate in the next breeding season, but club mates then become partners relatively seldom.


Author(s):  
V. A. Zubakin ◽  
◽  
E. V. Zubakina ◽  
A. V. Klenova ◽  
D. S. Vodolazova ◽  
...  

The crested auklet is a medium-sized planktivorous seabird of the Alcidae family with complex social behavior, one of the interesting forms of which is the formation of club pairs in addition to existing breeding pairs. The occurrence of club pairs in this species was studied on the Talan Island (Sea of Okhotsk) in 1988-1989, when the colony was in a good condition, and in 2008-2015, when its population decreased several times. The research showed that the proportion of individuals with club partners is higher in a high-population period (35 %) and lower in a low-population period (18 %); the differences, however, are not significant. In both study periods, from 73% (1988-1989) to 80 % (2008-2015) individuals were consistent in following the chosen strategy of forming or not forming club pairs for at least two seasons. The presence of club pairs seems to facilitate the change of mate in the next breeding season, but club mates then become partners relatively seldom.


2010 ◽  
Vol 124 (3) ◽  
pp. 219
Author(s):  
C. Stuart Houston ◽  
Frank Scott ◽  
Rob B. Tether

Between 1975 and 2002, diminished breeding success of Ospreys was associated with drought and falling lake levels in the western half of our study area near the town of Loon Lake, west-central Saskatchewan. Only 46% of nest attempts were successful in the west compared to 72% in the east, producing 0.88 young per accessible nest in the west and 1.42 in the east. Breeding success was greater in the eastern half, where water levels were stable, in spite of increased human use of the resort lakes there. Our unique long-term Canadian data base results support Ogden's 1977 prediction that Osprey productivity may decrease when water levels drop and fish populations are reduced.


2016 ◽  
Vol 27 (1) ◽  
pp. 140-152 ◽  
Author(s):  
DANA G. SCHABO ◽  
SONJA HEUNER ◽  
MICHAEL V. NEETHLING ◽  
SASCHA RÖSNER ◽  
ROGER UYS ◽  
...  

SummaryThe number of vultures is declining in many parts of the world due to numerous threats, such as poisoning and collisions with power-lines as well as the lack of adequate food sources. Vulture restaurants, i.e. supplementary feeding stations, have become a widespread conservation tool aimed at supporting vulture colonies. However, it is poorly understood how vulture restaurants influence population dynamics and whether they affect breeding success of vulture populations. We used a 12-year dataset from a breeding colony of the Cape Vulture Gyps coprotheres and a nearby vulture restaurant in South Africa to investigate the effect of supplementary food on population dynamics and breeding success. We found a significantly positive effect of supplementary food during the nest-building stage on the number of breeding pairs. However, breeding success, i.e. the proportion of successful nests, did not depend on supplementary food during the incubation and rearing stage. Especially during the critical rearing stage, the amount of food supplied might not have been sufficient to meet food demands of the colony. Still, our results indicate that carefully managed vulture restaurants might stabilise vulture colonies and can therefore aid vulture conservation.


2006 ◽  
Vol 80 (4) ◽  
pp. 409-415 ◽  
Author(s):  
R.A.H. Draycott ◽  
M.I.A. Woodburn ◽  
D.E. Ling ◽  
R.B. Sage

AbstractIn Great Britain free-living common pheasantsPhasianus colchicusare often managed at high densities owing to their popularity as a quarry species. They are prone to infection by a range of parasite species includingHeterakis gallinarum,Capillariaspp. andSyngamus trachea. In 1995 the efficacy of an indirect anthelmintic technique for controlling parasitic worm burdens of pheasants was determined in a pilot study on a shooting estate in the south of England. Between 2000 and 2003 a large-scale field experiment was conducted on nine estates in eastern England to determine the effect of the technique on parasite burden and pheasant breeding success. In the absence of anthelmintic treatment worm burdens increased rapidly through March and April, whereas birds given anthelmintic-treated grain had lower worm burdens during the same period. The breeding success of pheasants was significantly higher on plots provided with anthelmintic treatment, although no long-term increases in population densities were observed. The burdens of the most common parasiteH. gallinarumwere significantly lower in pheasants from treatment plots six weeks after the anthelmintic treatment had ceased, but spring treatment did not influence parasite burden in the following winter.


2000 ◽  
Vol 51 (4) ◽  
pp. 355 ◽  
Author(s):  
Peter Dann ◽  
F. I. Norman ◽  
J. M. Cullen ◽  
F. J. Neira ◽  
A. Chiaradia

In May 1995, numbers of little penguins, Eudyptula minor, coming ashore declined at Phillip Island and St Kilda concurrently with deaths of many penguins in western Victoria and a massive mortality of one of their food species (pilchard) throughout southern Australia. Among 1926 dead penguins reported were 131 banded birdsrecovered from Phillip Island (86% adults and 14% first-year birds), 26 from Rabbit Island and six from St Kilda. The number of banded penguins found dead per number of adult Phillip Island birds at risk was 2.3% in 1995 compared with an annual mean of 0.7% for 1970–93. Of 29 corpses autopsied, at least 26 died of starvation associated with mild–severe gastro-intestinal parasitism. Following the pilchard mortality, egg-laying by penguins in the subsequent breeding season (1995–96) was ~2 weeks later than the long-term mean and 0.3 chicks were fledged per pair compared with the long-term mean of 1.0. Unlike previous years, few penguins were recorded in Port Phillip Bay in September–October 1995, a period when pilchard schools were infrequently seen. It is concluded that the increase in penguin mortality in northern Bass Strait and the significant reduction in breeding success were associated with the widespread pilchard mortality.


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