Failure to launch: evidence of protracted parental care in albatrosses (original) (raw)
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Influence of Parental Experience on the Growth of Wandering Albatross Chicks
The Condor, 1990
The growth of the chicks and pattern of feeds to the chicks were studied for Wandering Albatross pairs (Diomedea exulans) with (1) no previous breeding experience, (2) a limited experience, and (3) an extensive experience. Chicks of inexperienced pairs grew more slowly than those of experienced pairs only during the first part of the fledging period and they had similar dimensions and weights when they left the colony. These differences resulted from different patterns of food delivery to the chicks during the first part of the fledging period; chicks of inexperienced pairs being fed less regularly but with larger meals than those of experienced pairs. The patterns of chick feedings were similar in the two categories during the second part of the fledging period. There was no difference between the feeding patterns for chicks of pairs with either an extensive or a limited experience and small differences in growth appeared only during the first weeks of life of the chicks, probably because of differences in egg size. These results suggest that first-time breeders are slightly less efficient at feeding the chick than experienced birds, but they attain similar skills within a few months, and pairs do not increase their efficiency after a first fledging attempt.
Post-fledging survival and dispersal of shy albatross from three breeding colonies in Tasmania
Marine Ecology Progress Series, 2010
Limited knowledge of the movements of post-fledging albatross represents a significant gap in understanding albatross biology and conservation. Without clearer understanding of at-sea distribution and mortality during this life-history stage, the threats to albatrosses cannot be managed appropriately. We investigated this early at-sea behaviour of shy albatrosses Thalassarche cauta, which breed only in Tasmania. We deployed 48 satellite transmitters on fledgling birds from each of the 3 Tasmanian populations over 4 separate seasons. We observed population differences in the atsea distribution, with the northern Albatross Island population foraging exclusively in southern Australian shelf waters to the west of the breeding colony. Birds from the 2 populations in southern Tasmania (Mewstone and Pedra Branca) also favoured these areas; however, they showed greater tendency to traverse the high seas and forage further west. These differences in spatial distribution mean populations have different exposure to fisheries and consequent risk of bycatch. Analysis of the satellite data and supporting evidence from band recoveries showed that juvenile mortality is highest in the period immediately after fledging. We speculate that this is related to foraging failure of naive birds. Differences between the 3 populations in post-fledging mortality were apparent. Albatross Island birds have greater chance of surviving the crucial initial learning period after fledging than either of the 2 southern populations, possibly due to proximity to food resources.
The albatross of assessing and managing risk for long-lived pelagic seabirds
Biological Conservation, 2018
Pelagic predators such as albatross have long been of conservation concern, but assessing their status poses numerous challenges. A standard monitoring method for albatross is colony-based nest counts to track numbers of breeders. However, a variable proportion of the population skips breeding in any given year and cannot be quantified by nest counts, creating several complications to efforts in understanding population dynamics. We used stochastic demographic matrix models for black-footed (Phoebastria nigripes) and Laysan (P. immutabilis) albatross to investigate: i) the potential for the skipping behavior of breeders to create apparent density dependence in nest counts, ii) the limitations to assessing population trends from nest counts and implications for evaluating impacts from fisheries bycatch, including calculating Potential Biological Removal values, and iii) the relative importance of at-sea versus on-island threats to population viability. We found the increased likelihood of these albatrosses skipping breeding following a successful seasona feature common to many seabirds and other taxaresults in substantial negative temporal auto-correlation in the observable population that can be misinterpreted as negative density dependence, with important implications for inferences about population viability. Black-footed albatross appear limited by fisheries bycatch, while Laysan albatross, which have low estimated bycatch mortality, are currently at greater risk from island-based threats. Our results suggest a cautionary approach to managing black-footed and Laysan albatross should be adopted because detecting population declines from nest counts could take decades. Ultimately, we highlight the inherent difficulties in assessing population status and trends in long-lived species such as albatross.
Translocation and hand-rearing techniques for establishing a colony of threatened albatross
Bird Conservation International, 2012
Many breeding colonies of Procellariiformes have been threatened with extinction. Chick translocation has been shown to be an effective method for establishing new "safer" colonies of burrow-nesting species, but techniques for surface-nesting species have not been fully developed. The entire breeding population of the threatened Short-tailed Albatross Phoebastoria albatrus is restricted to two sites, Torishima Island and the Senkaku Islands, and neither site is secure due to volcanic activity or political instability. The Short-tailed Albatross Recovery Team has recommended facilitating the recovery of this species by establishing at least one additional colony through the translocation and hand-rearing of chicks at a safe historical breeding site. To evaluate the feasibility of this approach, we hand-reared 10 post-guard phase chicks of two related species in 2006-2007: Laysan Albatross P. immutabilis translocated from Midway Atoll to Kaua'i Island, Hawai'i and Black-footed Albatross P. nigripes translocated from a nearby islet in the Ogasawara (Bonin) Islands to Mukojima Island, Japan. In these pilot studies, 40% of Laysan Albatross chicks and 90% of Black-footed Albatross chicks fledged successfully. Following this groundwork, 40 post-guard phase Short-tailed Albatross chicks were translocated from Torishima Island to Mukojima Island in February 2008-2010 and hand-reared to fledging. Their fledging success has been 100% in all three years. Fledging body sizes were similar or greater in hand-reared chicks at the release site than parent-reared chicks on Torishima Island. There were significant differences in levels of some blood chemistry parameters between pre-fledging hand-reared and parent-reared chicks. The techniques developed in our studies have broad-reaching implications for the future conservation of threatened populations of other surface-nesting seabirds.
Ibis, 2008
For most seabirds, reproductive performance improves with age; in albatrosses this is thought not to be so (experience being acquired before starting breeding) but only one study (of chick growth in a single season at one site) has specifically addressed this. We compared the provisioning performance and growth rates of chicks of Wandering Albatrosses Diornedea exulans breeding for the first (IN), second and third (LE) and fourth or more times (EE) on Bird Island, South Georgia in the austral winters of 1996 and 1997. Eggs from EE adults were significantly heavier than the other two categories and these chicks had a greater mass and longer wings up to 160 days of age and longer culmen and tarsus u p t o 11 5 days old. However chicks from all categories fledged at the same average mass, size and age. No significant differences between categories in feeding
An Artificial Rearing Experiment of Laysan Albatross Chicks
Journal of the Yamashina Institute for Ornithology, 2008
The population of endangered Short-tailed Albatrosses Phoebastria albatrus has gradually increased through great conservational e#orts, but their only two breeding sites, Torishima Island and Senkaku Islands, have a high risk of volcanic eruption or political problems. The Short-tailed Albatross Recovery Team has indicated that, to achieve recovery of this species, additional breeding colonies of the Short-tailed Albatross must be established. Their proposed plan is to artificially rear chicks translocated from Torishima Island at new safe sites. To evaluate the feasibility of this approach, it is important that trials first be conducted with related albatross species. In early March of 2006, 10 Laysan Albatross P. immutabilis, approximately one month of age, were captured at Midway Atoll and moved to Kauai Island, where we attempted to rear them to fledging in early July. Chicks were provided daily with 250῍450 g of squid and lake smelt as food. This amount was estimated from a regression equation derived from the proportion of daily amount of food to body mass and daily increase of body mass in the Grey-headed Albatross Diomedea chrysostoma. This species has a similar growth pattern as the Laysan Albatross. We also provided vitamins and other supplements to compensate for nutritional deficiencies in the diet, along with some electrolyte solution to prevent dehydration. Three and two chicks died during one month after beginning to rear and just before fledging, respectively. One chick with an injured wing and no prospect of flying was housed at Monterey Bay Aquarium. The remaining four chicks fledged successfully. Sources of
Journal of Avian Biology, 2010
In birds, the period spent brooding or guarding young chicks is highly variable, but such variation has seldom been studied. Previous single-year studies of Antarctic petrels Thalassoica antarctica and grey-headed albatrosses Thalassarche chrysostoma revealed a pronounced seasonal decline in brood-guarding duration and gave rise to the 'synchronisation hypothesis', which suggests that some of the variation in the length of the brood-guarding stage is related to predictable seasonal changes in the risk of chick predation. We tested the predictions of this and three other hypotheses in a two-site, four-year study of the black-browed albatross T. melanophris. The existence of a pronounced seasonal decline in broodguarding duration was apparent at both sites, and in years of contrasting food availability, providing further support for the 'synchronisation hypothesis'. Alternative explanations for this pattern are that short brood-guarding periods for latehatched chicks result from a seasonal decline in food availability or from the fact that early nesting birds are of higher individual quality. However, these explanations are at odds with the absence of a seasonal decline in early chick growth or in probability of chick survival. Furthermore, adult quality (measured as past reproductive performance) had a weak and inconsistent effect on the duration of brood-guarding. Weather changes explained some of the variation in broodguarding, but there were no differences between regions of contrasting climates. Individual pairs displayed a degree of inter-annual consistency in brood-guarding duration and, at least in some years, longer brood-guarding resulted in higher fledging probability. We speculate that a higher investment in brood-guarding increases the cost of reproduction, which counteracts other selective pressures that would otherwise lead to longer brood-guarding durations.
PROVISIONING AND GROWTH RATES OF SHY ALBATROSSES AT ALBATROSS ISLAND, TASMANIA
The Condor, 2002
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Marine Ecology Progress Series, 2005
To understand how seabird breeding performance is influenced by environmental variability, it is necessary to compare acquisition processes between contrasted situations, and their consequence for reproduction. We present results on variations in distribution at sea, habitat selection, diet and provisioning behaviour of the yellow-nosed albatross Thalassarche chlororhynchos from Amsterdam Island, and their consequence for chick growth, during 2 years, 1996 and 2001, with contrasted environmental conditions. The position of thermal fronts changed between the 2 years, and the waters around Amsterdam were colder in 2001 than in 1996. Satellite tracking and compositional analysis show that in 2001 birds foraged farther and in colder oceanic waters than in 1996, resulting in poorer foraging success in 2001. During both years, fish dominated the diet, with minor interannual differences: albatrosses fed more on fish (including a higher proportion of the nomeid Cubiceps caeruleus) and less on squid and crustaceans in 1996. Nestling provisioning was half the rate in 2001 compared to 1996, and this difference was mainly due to longer trips in 2001, with a bimodal trip length distribution. Consequently, chick growth differed significantly, with lighter chicks at fledging being produced in 2001 compared to 1996, although wing length was similar between the 2 years. This study indicates that, during unfavourable conditions, yellow-nosed albatrosses are able to increase foraging effort by searching for prey at greater distances from the nest, at the expense of offspring condition.