Phoebastria immutabilis: BirdLife International

Author(s):  
2018 ◽  
Vol 25 (1) ◽  
pp. 19-22
Author(s):  
Jin-Won Yang ◽  
Seung-Gu Kang ◽  
Won-Ho Lee ◽  
Meong-Kyu Jeong

2009 ◽  
Author(s):  
Jill A. Awkerman ◽  
David J. Anderson ◽  
G. Causey Whittow

2008 ◽  
Vol 4 (4) ◽  
pp. 323-325 ◽  
Author(s):  
Lindsay C Young ◽  
Brenda J Zaun ◽  
Eric A VanderWerf

Unrelated same-sex individuals pairing together and cooperating to raise offspring over many years is a rare occurrence in the animal kingdom. Cooperative breeding, in which animals help raise offspring that are not their own, is often attributed to kin selection when individuals are related, or altruism when individuals are unrelated. Here we document long-term pairing of unrelated female Laysan albatross ( Phoebastria immutabilis ) and show how cooperation may have arisen as a result of a skewed sex ratio in this species. Thirty-one per cent of Laysan albatross pairs on Oahu were female–female, and the overall sex ratio was 59% females as a result of female-biased immigration. Female–female pairs fledged fewer offspring than male–female pairs, but this was a better alternative than not breeding. In most female–female pairs that raised a chick in more than 1 year, at least one offspring was genetically related to each female, indicating that both females had opportunities to reproduce. These results demonstrate how changes in the sex ratio of a population can shift the social structure and cause cooperative behaviour to arise in a monogamous species, and they also underscore the importance of genetically sexing monomorphic species.


2015 ◽  
Vol 21 (1) ◽  
pp. 38 ◽  
Author(s):  
Bayard H. Brattstrom

Long-term ecological studies are desirable, but rare. I here present data from a 60-year study on the repopulation of San Benedicto Island following a volcano eruption in 1952. Bárcena Volcano appeared on 1 August 1952 on San Benedicto Island, Revillagigedo Islands, Mexico. Within 20 min, the entire island was engulfed in a cloud of ash and pumice, which covered all the plants, killed an estimated 20 000 sea birds within hours and caused the subsequent extinction of an endemic race of rock wren (Salpinctes obsoleta exsul). The results of studies on revegetation and repopulation of the island for the first 10 years after the volcanic eruption were summarised by Brattstrom in 1963. This report extends the studies to 2012. The distribution of the land crab (Aegecarcinus planatus) has increased on the island. By 1971 the crab occurred only over the northern one-eighth of the island, but by 1978 it could be found on one-third of the island. No studies on its distribution have been made since then. Total sea bird populations steadily increased up to 1971 and then rapidly declined, though these changes in numbers are largely due to a fluctuation in the populations of the masked booby (Sula dactylatra). The changes in the booby population may have been due to reproductive and feeding success or to immigration and emigration. The decline in the shearwater (Puffinus ssp.) populations are largely due to erosion and destruction of their burrows; their numbers did not increase until 2000. The formation of a large lava delta created a new habitat, which permitted the establishment of a species of sea bird new to the island, the red-footed booby (Sula sula). Numerous non-resident waifs or stray birds have been observed on the island but most have not become established. The exception is the Laysan albatross (Phoebastria immutabilis), breeding at present in low (3–712) numbers. The original flora consisted of 10 species. The volcano caused four species to become extinct, two re-established themselves, and two species new to the island arrived. There have been marked erosional changes, and the accidental introduction of exotic plants may dramatically alter the vegetation of the island.


The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 577-584
Author(s):  
Patricia Fernández ◽  
David J. Anderson

Abstract We used a new immersion monitor to study the foraging movements of two species of albatrosses that nest in the Hawaiian Islands. The monitors showed that breeding male Black-footed Albatrosses (Phoebastria nigripes) land on the water more frequently during the day than at night. Breeding male Laysan Albatross (Phoebastria immutabilis) behavior was more variable and also showed a diurnal bias. We found no evidence of a nocturnal foraging bias in either species; in particular, these species do not seem to be limited to live capture of nocturnally available squid. Such squid may, nonetheless, contribute to the diet as a result of scavenging.


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