Mortality and breeding failure of little penguins, Eudyptula minor, in Victoria, 1995 - 96, following a widespread mortality of pilchard, Sardinops sagax

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.

Download Full-text

Effects of the Iron Baron oil spill on little penguins (Eudyptula minor). III. Breeding success of rehabilitated oiled birds

Wildlife Research ◽

10.1071/wr99077 ◽

2000 ◽

Vol 27 (6) ◽

pp. 583 ◽

Cited By ~ 19

Author(s):

M. Giese ◽

S. D. Goldsworthy ◽

R. Gales ◽

N. Brothers ◽

J. Hamill

Keyword(s):

Breeding Season ◽

Oil Spill ◽

Breeding Success ◽

Egg Laying ◽

Long Term Effects ◽

Short Term ◽

Significant Difference ◽

Breeding Seasons

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.

Download Full-text

Breeding biology of coppersmith barbet, Megalaima haemacephala (Müller, 1776)

University Journal of Zoology Rajshahi University ◽

10.3329/ujzru.v31i0.15397 ◽

2013 ◽

Vol 31 ◽

pp. 31-34

Author(s):

Noor Jahan Sarker ◽

M Firoj Jaman ◽

Shariar Mustafa ◽

Md Saidur Rahman

Keyword(s):

Incubation Period ◽

Breeding Season ◽

Breeding Success ◽

Brood Size ◽

Botanical Garden ◽

Egg Laying ◽

Breeding Biology ◽

Average Weight ◽

Average Height ◽

Average Depth

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

Download Full-text

Fitness increases with partner and neighbour allopreening

Biology Letters ◽

10.1098/rsbl.2007.0258 ◽

2007 ◽

Vol 3 (4) ◽

pp. 386-389 ◽

Cited By ~ 31

Author(s):

Sue Lewis ◽

Gilbert Roberts ◽

Mike P Harris ◽

Carina Prigmore ◽

Sarah Wanless

Keyword(s):

Breeding Success ◽

Negative Relationship ◽

Uria Aalge ◽

Social Functions ◽

Common Guillemot ◽

Breeding Failure ◽

Animal Societies

Altruism and selfishness are fundamental characteristics of human and animal societies. Among colonial biparental species, breeding outcome depends on interactions between mates and neighbours. However, the relationships between cooperation within and among partnerships and fitness have not been fully investigated. We show that in the highly colonial common guillemot ( Uria aalge ), altruistic behaviour (allopreening) towards a mate was positively related to long-term fitness, whereas allopreening a neighbour was related to current fitness. Turnover is much lower within than between pairs, so our results suggest that allopreening within pairs generates fitness returns at longer timescales than between pairs. Allopreening not only removes ectoparasites and maintains plumage condition, but may also have important social functions. We found a negative relationship between fight rate and allopreen rate between breeding neighbours, with nests exhibiting low breeding success having a higher frequency of fights with neighbours. We also found evidence for reciprocity in allopreening. Thus, allopreening may function as a reciprocal stress reducer, to decrease the likelihood of fights and associated breeding failure. We suggest that altruistic behaviour has long-term benefits for the survival of the offspring when living in a crowded neighbourhood.

Download Full-text

Territory size and polygyny in the spotless starling: resource-holding potential or social inertia?

Canadian Journal of Zoology ◽

10.1139/z01-161 ◽

2001 ◽

Vol 79 (11) ◽

pp. 1951-1956 ◽

Cited By ~ 29

Author(s):

José P Veiga ◽

Juan Moreno ◽

Pedro J Cordero ◽

Eduardo Mínguez

Keyword(s):

Breeding Success ◽

Territory Size ◽

First Year ◽

Female Reproduction ◽

Resource Holding Potential ◽

Nest Boxes ◽

Breeding Territory ◽

Territory Acquisition ◽

Contradictory Evidence

In male birds that base their acquisition of mates on the defence of resources essential for female reproduction, the size or quality of the territory decisively affects polygyny rate and breeding success. However, there is contradictory evidence concerning the importance of resource-holding potential (RHP) versus factors not related to individual quality on between-year consistency in territory occupancy and hence on long-term reproductive success. We manipulated the aggressiveness (a major determinant of RHP) of male spotless starlings (Sturnus unicolor) by means of androgens and antiandrogens to investigate the importance of RHP in breeding-territory acquisition and maintenance, polygyny rate, and breeding success over 3 years (19961998). The number of males that held a territory for the first time was high in 1996 with respect to the year before the experiment began. Most of these males still bred in the colony during the third study year, though new owners established territories to the detriment of the former males, especially in 1998. Manipulation of testosterone activity during the first year affected the number of nest boxes defended by males and also the number of mates gained and the number of successful breeding attempts made throughout the 3 study years. The results were in the expected direction: an increase in testosterone activity led to greater success. The results suggest that RHP may be important in the acquisition of territory and mates, at least under conditions of recently established interindividual relationships. However, social inertia, i.e., the maintenance of dominance status irrespective of changes in RHP, seems to be of crucial importance in the long-term maintenance of territory resources and polygyny rates.

Download Full-text

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

Australian Journal of Zoology ◽

10.1071/zo97040 ◽

1998 ◽

Vol 46 (2) ◽

pp. 119 ◽

Cited By ~ 20

Author(s):

Elizabeth A. Krebs

Keyword(s):

Breeding Season ◽

Breeding Success ◽

Brood Size ◽

Hatching Success ◽

Egg Laying ◽

Hatching Asynchrony ◽

Strongly Correlated ◽

Australian Capital Territory ◽

Egg Destruction ◽

Black Mountain

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.

Download Full-text

Estimates of productivity and detection probabilities of breeding attempts in the sooty shearwater (Puffinus griseus), a burrow-nesting petrel

Wildlife Research ◽

10.1071/wr06074 ◽

2009 ◽

Vol 36 (2) ◽

pp. 159 ◽

Cited By ~ 15

Author(s):

Jamie Newman ◽

David Fletcher ◽

Henrik Moller ◽

Corey Bragg ◽

Darren Scott ◽

...

Keyword(s):

Breeding Season ◽

Breeding Success ◽

Infrared Camera ◽

Egg Laying ◽

Imperfect Detection ◽

Camera System ◽

Variable Effect ◽

Average Proportion ◽

Breeding Attempt ◽

Two Stages

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.

Download Full-text