Breeding success and causes of breeding failure of curlewNumenius arquatain Northern Ireland

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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The diet of white-chinned petrels Procellaria aequinoctialis, Linnaeus 1758, in years of contrasting prey availability at South Georgia

Antarctic Science ◽

10.1017/s0954102099000371 ◽

1999 ◽

Vol 11 (3) ◽

pp. 283-292 ◽

Cited By ~ 21

Author(s):

Simon D. Berrow ◽

John P. Croxall

Keyword(s):

Breeding Success ◽

Prey Item ◽

Prey Availability ◽

Euphausia Superba ◽

Feeding Frequency ◽

South Georgia ◽

Important Prey ◽

Breeding Failure ◽

Feeding Methods ◽

Procellaria Aequinoctialis

The diet of breeding white-chinned petrels was studied during the summers of 1996 and 1998 at South Georgia. Krill abundance/availability was high throughout 1996 but apparently low at the beginning of the 1998 breeding season. The diet of white-chinned petrels was similar between years and consistent with previous studies. Krill Euphausia superba (41–42% by weight) was the single most important prey item followed by fish (39–29%) and squid (19–25%). Meal mass was consistent (110 g in 1996, 119 g in 1998) between years but a significant decrease (46%) in feeding frequency in 1998 (0.54 meals day−1 compared to 0.75 meals day−1 in 1996) resulted in 19% less food delivered to chicks in 1998 than in 1996. Breeding success, however, was consistent between years at 44% and similar to that recorded previously at Bird Island. This is in contrast to black-browed and grey-headed albatrosses, both of which experienced almost total breeding failure in 1998. It is suggested that their varied and versatile feeding methods, together with their greater diving ability, capacity to feed at night and extensive foraging range, help white-chinned petrels minimise the effects of krill shortage.

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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.

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Feral pigeons as a nest competitor for a small seabird

10.21203/rs.3.rs-550854/v1 ◽

2021 ◽

Author(s):

Beneharo Rodríguez ◽

Airam Rodríguez ◽

Felipe Siverio ◽

Juan Manuel Martínez ◽

Enrique Sacramento ◽

...

Keyword(s):

Breeding Success ◽

Columba Livia ◽

Pathogen Transmission ◽

Nest Density ◽

Nest Location ◽

Nest Sites ◽

Breeding Failure ◽

Nesting Sites ◽

Calonectris Borealis

Abstract Due to their life-history traits, the petrels are particularly sensitive to predation by introduced species. Therefore, many populations have constricted their original breeding distribution range, currently only occupying predator-free sites. In this scenario, interspecific competition for nesting sites can be detrimental for the petrel’ conservation. Here, we evaluate how the presence of introduced mammals (cats Felis catus and rats Rattus spp.) and potential competitors for nest sites (Cory’s shearwaters Calonectris borealis and feral rock pigeons Columba livia) shape the distribution, breeding density, and breeding performance of the Bulwer’s petrel Bulweria bulwerii on Tenerife, the largest and most densely populated of the Canary Islands. We estimated nest density, assessed the role of nest location and nest characteristics on breeding success, and determined causes of breeding failure by exotic predators and competitors. Nest density was higher in predator-free colonies on marine rocks. Cat presence was the best predictor for nest density, while presence or abundance of competitors had no correlation to nest density. Breeding success varied between years and colonies, but was not related to nest characteristics. Of the unequivocally determined causes of breeding failure, pigeon competition for nests was the most frequent (7.3%), followed by rat predation (6.3%). We also compared petrel and pigeon nest cavities and found a considerable overlap in nesting niche. Our study provides insight on an overlooked impact of the invasive rock pigeon: nest competition with small seabirds. We encourage more research on the effects of pigeons on nest density, disease and pathogen transmission, and vegetation changes within petrel colonies.

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Predation at Sooty Shearwater Puffinus griseus colonies on the New Zealand mainland: is there safety in numbers?

Pacific Conservation Biology ◽

10.1071/pc000347 ◽

1999 ◽

Vol 5 (4) ◽

pp. 347 ◽

Cited By ~ 1

Keyword(s):

New Zealand ◽

Conceptual Model ◽

Breeding Success ◽

Rattus Norvegicus ◽

Breeding Birds ◽

Breeding Failure ◽

Safety In Numbers ◽

Breeding Seasons ◽

Norway Rats ◽

Extinction Vortex

Burrow occupancy, survivorship, and breeding success were assessed at eight Sooty Shearwater Puffinus griseus colonies along the southeastern coast of New Zealand during the 1994/95 and 1995/96 breeding seasons. An average 46% and 47% of burrows contained breeding birds, but only three colonies had chicks survive to fledge. Most breeding failures were at the egg and early-chick phase. A large proportion of adults were killed at some places, causing the extinction of two of our study colonies. Predation by Stoats Mustefa erminea was the main cause of breeding failure and adult loss at most mainland colonies, but Norway Rats Rattus norvegicus were the principal predator at one colony. Protection of adults, eggs and young chicks from predators is crucial if mainland colonies are to persist. A conceptual model predicts that predation becomes part of the extinction vortex as the size of a colony dwindles because the depredations of a few rogue predators have catastrophic impacts on the few remaining birds.

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