Breeding biology of crimson rosellas (Platycercus elegans) on Black Mountain, Australian Capital Territory

1998 ◽  
Vol 46 (2) ◽  
pp. 119 ◽  
Author(s):  
Elizabeth A. Krebs

The breeding behaviour of crimson rosellas (Platycercus elegans) in Canberra, Australia, was studied between 1993 and 1996. Female rosellas initiated breeding in late September or early October, laying a mean of 5.3 ± 0.1 (s.e.) eggs at 1–4-day intervals. Of all eggs laid, 50% fledged successfully. Rosellas had the highest breeding success in the wettest year (1995), when they bred earlier, laid larger clutches and fledged more young. Unexpectedly, breeding success was not lowest in the driest year (1994), although fewer birds attempted breeding and hatching success was low. In this study, poor environmental conditions for breeding were counterbalanced by decreased levels of conspecific interference through egg destruction. Overall, 55.8% of all clutches initiated were destroyed during laying, and more than half of this was attributed to rosellas. The reasons for egg destruction by rosellas were not clear. Boxes where clutches were destroyed were not quickly reoccupied and egg destruction was not highest when competition for nesting hollows was most intense. Clutch size and egg-laying intervals decreased over the breeding season, but the length of incubation did not. Large clutches did not produce more fledglings, because more eggs failed to hatch, especially early in the season. Eggs in a clutch hatched over a period of 0.5–7 days. Total hatching asynchrony increased over the breeding season and was not strongly correlated with clutch or brood size. This suggests that female rosellas initiated incubation at different times during laying. Clutches with longer hatching intervals took longer to incubate. If females in poor condition are inefficient incubators, female condition may affect the degree of hatching asynchrony.

2013 ◽  
Vol 31 ◽  
pp. 31-34
Author(s):  
Noor Jahan Sarker ◽  
M Firoj Jaman ◽  
Shariar Mustafa ◽  
Md Saidur Rahman

Breeding biology of the Coppersmith barbet, Megalaima haemacephala (Müller, 1776) was carried out between February, 2006 and January, 2007 at Sharawardy Uddyan, Ramna Park, Curzon Hall and National Botanical Garden. The breeding season started from December and ended in June. In total 20 nests were observed, of which 10 nests were studied in details in four study areas. The coppersmith barbet mostly preferred to make holes on the branches of koroi (Albizzia procera) for nesting. Egg laying started on 15th February in the study areas. Average height of nests from the ground was 9.7m and average depth and diameter of the holes was 29.20cm and 4.46cm respectively. New holes were constructed yearly or the old one was reused. Both the sexes took part in incubation of eggs, brooding and feeding to the nestlings. A total of 30 eggs were laid in 10 nests. Clutch size varied from 2 – 4 eggs (average: 3 eggs). Among them, 20 (66.67%) eggs were hatched and the rest 10 (33.33%) were unhatched and lost. Average incubation period was 14 days. The male and the female incubated the eggs for an average of 27.44 minutes/ hours and 32.56 minutes/ hours, respectively. Average number of nestlings (brood size) per nest was 2. Out of 20 nestlings, 16 left their nests successively. The breeding success was 53.33% in relation to the number of eggs laid and 80% in relation to nestlings hatched. The average weight of eggs and nestlings was 3.59g and 9.33g, respectively. The main causes of loss of the eggs and nestlings were human interference, predation and ectoparasitic infections. Insects and fruits were fed to the nestlings by their parents.DOI: http://dx.doi.org/10.3329/ujzru.v31i0.15397Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 31-34 


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.


2021 ◽  
Vol 47 (1) ◽  
pp. 23-34
Author(s):  
Habibon Naher ◽  
Noor Jahan Sarker ◽  
Shawkat Imam Khan

The breeding biology of the common kingfisher (Alcedo atthis) was studied from 2008 to 2011 in Dhaka North City Corporation and Savar Upazilla. The breeding season was April to September. It laid 3 to 7 glossy white, almost round eggs with a size of 2.5±0.3 cm length, 2.2±0.3 cm breadth, and 5.3±0.7g weight. It incubated for 16 to 21 days. During hatching, the hatchlings’ weight ranged from 8.5 to 10.5 g and total body length from 43.2 to 58.6 mm whereas, it was 30.1 to 32.7 g and 151 to 155.5 mm, respectively, during fledging. Hatching success was 83.3%. Stolen by people (13.9%) and infertility (2.8%) were the causes of egg loss. The young birds fledged out after 21 to 27 days of hatching. A total of 56.7% of nestlings were unable to fly due to stolen (43.3%), deaths due to unknown reasons (6.7%) and deaths due to natural disaster (6.7%). The breeding success was 36.1% in relation to eggs laid and 43.3% in relation to eggs hatched. J. Asiat. Soc. Bangladesh, Sci. 47(1): 23-34, June 2021


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.


Zoodiversity ◽  
2021 ◽  
Vol 55 (3) ◽  
pp. 201-206
Author(s):  
N. Boukrouma

The Pied Avocet (Recurvirostra avosetta Linnaeus, 1758) is a sedentary species in Northeastern Algeria, although numbers present increase during spring and summer. Nesting occurs on the dikes and lakes placed at the different pools of the saltpans. In this study, the breeding ecology of the Pied Avocet was studied during the 2017 breeding season in Tiffech lake wetland (868 m in elevation), Northeastern Algeria. The Pied Avocets arrived, at Tiffech Lake in early February and usually spent a few days in flocks before dispersing to set up territories. Egg-laying occurred from 11 April to 21 June, with two distinct peaks (last 15 days of April and May) and incubation period was 27.0 days. The present study indicates the expanded, breeding season. Clutch and egg size of this high-elevation population was comparable to lowland counterparts. Hatching success was 85.77 % and mean net productivity was 0.63 chicks per nest. Entire nest failure from human predation and sheep grazing was responsible for most egg losses.


2009 ◽  
Vol 36 (2) ◽  
pp. 159 ◽  
Author(s):  
Jamie Newman ◽  
David Fletcher ◽  
Henrik Moller ◽  
Corey Bragg ◽  
Darren Scott ◽  
...  

Monitoring of breeding success in burrow-nesting seabirds is problematic, owing to the difficulties of detecting occupants in complex burrow systems. We summarise 6 years of monitoring the breeding success of sooty shearwater (tītī, muttonbird, Puffinus griseus) on two southern New Zealand islands, The Snares and Whenua Hou, with a portable infrared camera system. Breeding attempts were monitored three times during the breeding season, i.e. egg laying, hatching and fledging. Overall breeding success was calculated in two stages. First, we estimated breeding success for each island–site–year combination with a model that allowed for imperfect detection of an egg or chick and accounted for the proportion of the breeding season that was covered by monitoring. The resulting estimates for each island were then analysed with a linear model, to provide a single estimate for that island. Breeding success was found to be highly variable and non-synchronous between islands, with the average proportion of eggs successfully fledging on The Snares (0.35, 0.20–0.52; mean and 95% creditable interval) being considerably lower and more variable than that on Whenua Hou (0.76, 0.70–0.82). Probability of detecting a breeding attempt was higher on The Snares whereas correcting for the proportion of the season monitored had a variable effect, reducing The Snares and Whenua Hou estimates by 27% and 7% respectively. The implications of these findings with respect to the demographic modelling of burrow-nesting species are discussed.


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.


1986 ◽  
Vol 34 (3) ◽  
pp. 351 ◽  
Author(s):  
A Lill

Estimated expenditures on brood-care by unassisted female superb lyrebirds, obtained through time-energy budgeting, were compared with published values for other bird species. With the exception of nestbuilding, estimated daily expenditures were relatively low, due mainly to the small brood size and low level of parental attentiveness. It is suggested that the traits which reduce daily brood-care expenditures, particularly the small brood size and extremely slow growth rate, may have evolved as adaptations which enabled deserted females operating close to maximal capacity to cope with single-parenting. Male parental involvement could probably increase the growth rate of the young, but not brood size; moreover, egg- laying was sufficiently asynchronous to afford multiple mating opportunities to parentally emancipated males. However, the slow growth rate of the young results in relatively large overall brood-care expenditures for females. Investments by males of up to 50% of daylight hours and 45% of BMR on singing at the height of the mating season were comparable with those of partially emancipated, polygynous males of other species. They probably reflect the high level of competition to control good display areas and to advertise status and quality to widely spaced females.


2021 ◽  
Author(s):  
◽  
Kelly Maree Hare

<p>The conditions under which reptilian eggs are incubated affect survival probability and physiological attributes of the progeny. The egg-laying skink, Oligosoma suteri, is the only endemic oviparous lizard in New Zealand. No controlled laboratory incubation had previously been undertaken, and thus no information was available on the requirements for successful captive incubation. I studied the effects of incubation regime on the eggs and hatchlings of O. suteri to four months of age. Oligosoma suteri eggs (n = 174) were randomly distributed among three constant incubation temperatures (18°C, 22°C and 26°C) and two water potentials (-120 kPa and -270 kPa). Hatching success and hatchling survival were greatest at 22°C and 26°C, with hatchlings from 18°C incubation suffering from physical abnormalities. Incubation regime and maternal influence did not affect sex of individuals, with equal sex ratios occurring from each incubation treatment. Hatchlings from the 22°C and -120 kPa incubation treatments were larger, for most measurements, and warmer incubation temperatures resulted in increased growth rates. Juveniles from 22°C and 26°C and individuals with greater mass per unit length (condition index) sprinted faster over 0.25 m. Sprint speed was positively correlated with ambient temperature. At four months of age sprint speed decreased in 18°C individuals and individuals incubated at 26°C and -270 kPa compared to their performance at one month. The results suggest that the most successful captive incubation regime for O. suteri is 22°C and -120 kPa. This study also shows that temperature-dependent sex determination does not occur in O. suteri, but that fitness traits are influenced by incubation temperature.</p>


Koedoe ◽  
2002 ◽  
Vol 45 (2) ◽  
Author(s):  
D.A. Edge

The Brenton Blue butterfly, Orachrysops niobe (Trimen, 1862) (Lepidoptera:Lycaenidae), is endemic to the southern Cape and is currently listed as Endangered. This study looks at some of the key ecological factors influencing the breeding success of the species—host plant abundance and condition, nectar sources, climate/ microclimate, and vegetation management techniques. The adult butterfly population was monitored over an entire breeding season; host plants were identified and individually monitored; and egg counts were done. This enabled the effects of a number of different management techniques to be evaluated (burning, cutting, physical removal of invasive elements, and combinations thereof). A fivefold increase in the population of O. niobe was observed over the breeding season. This increase was positively correlated to a similar increase in host plant abundance in the areas where cutting and physical removal of invasive elements was practiced. Burning, by contrast, appeared to have a negative impact on host plant and butterfly abundance over the same period. Impacts of other factors such as climate, nectar sources and the natural strength of the second brood are discussed. A hypothesis, of megaherbivore activity as the principal historical disturbance mechanism promoting locally favourable conditions for O. niobe to establish and maintain colonies, is proposed. Recommendations for reserve management and future research are made.


Sign in / Sign up

Export Citation Format

Share Document