While the onset of winter marks the departure of most of Bird Island's wildlife, there's one iconic resident who stays with us through the cold, dark months.
The Wandering Albatross, Diomedea exulans, are truly amazing birds. They look unreal sometimes, like a huge relic of a prehistoric age as the adults stand well over a meter tall and can weigh more than 10kg. Their wingspan is the largest of any living bird, at up to 3.5 meters. That means they can soar above the oceans for hours at a time without expending any energy flapping, searching for food in the vastness beneath.
They mainly eat cephalopods but will readily take crustaceans, small fish and carrion. We regularly find regurgitated piles of squid beaks beside their nests which can be collected for measuring and identification to enhance our understanding of their diet – small changes may be indicative of greater changes to the marine ecosystem.
Wandering albatross are frequently seen from ships in the Southern Ocean. Described as a 'bird of good omen' by Coleridge, they can follow them for days, often feeding off any scraps thrown overboard. Unfortunately this has been hugely detrimental to their health as they can get caught, tangled up and drowned by the long-line fisheries boats. Advances are being made with deterrents and legislation about operating procedure, particularly around South Georgia where by-catch has been hugely reduced, but it continues to be a problem in less well regulated parts of the ocean.
|Copulating pair, an infrequent October sight.|
They build a nest out of mud, moss and tussack grass that will be used year after year and stands around 40cm high. These are spread in loose colonies across the island. In mid to late December a single egg, white and 10cm long is laid and incubated by both parents.
|Chick on the nest with both parents present.|
Between Christmas and New Year the albatross assistants, with as much help as is available, cover the whole island counting and marking each nest with a numbered stake and GPS plot point so we can map them. Where possible we'll record ring numbers of both birds – this often means repeated return visits as each one can be away from the nest for well over a week. There is a ridge behind the base where the birds are studied more intensively; they carry coloured darvic rings so they can be identified with minimum disturbance and at times the area is visited daily to get precise laying and hatching dates.
|Checking for eggs. The clipboard is useful not only for making notes but also as a bit of protection. The birds are not particularly aggressive but those beaks are big and sharp.|
With this simple long-term monitoring we can build up a life history of the population, looking at changing trends in survival rates, life expectancy and breeding success. With such long-lived birds, over 50 years, it's important to have consistent monitoring techniques so we can draw comparisons over time and with other locations.
While the established pairs are alternating time between egg-sitting and fishing the younger, unpaired birds are searching for partners. Wanderers are monogamous and generally mate for life but there's always single birds trying to impress others. They gather in groups and show off by spreading their wings, throwing their heads back and uttering a variety of gurgles, screams, whistles, grunts and snapping. Later on they may tap their bills together and mutually preen each other. These rituals are repeated by long-term pairs re-establishing their bonds.
|Young male (front) spreading his wings and skycalling to impress the female on the right. Behind him another copies his obviously impressive chat-up techniques.|
|A long-term pair preening each other to re-affirm their partnership.|
Incubation takes the best part of three months. Once the egg hatches the adults continue taking turns looking after the chick for another few weeks. By the time it's old enough to be left alone, early April, they've got a deep layer of downy feathers over an inch thick and the ability to vomit oily, plumage-ruining sick on anyone they perceive to be a danger. Despite this defence many Wanderer nest sites have been decimated by introduced land predators such as cats, rats and mice. One of the reasons Bird Island is so important is that it has never hosted these predators and it is hoped that the rat eradication on the South Georgia mainland will re-open historic breeding grounds.
|Young chick being preened and cared for by a parent.|
|Poking a head out from under a leg for a view of the outside world.|
As the winter approaches and the island gets covered with snow and ice the chicks sit tight on their nests, islands of warmth amongst the inhospitable cold. During the harshest storms they sit tight, curled up asleep with their heads tucked down. During this time they are visited roughly once a week by each parent, returning with a belly full of rich food that they regurgitate straight into the hungry chicks.
|When snow covers the island all that stands out are these small balls of warmth.|
|Young chick getting a delicious, oily snack.|
Throughout the season the nests are visited at the start of every month to check which ones have hatched, how the chicks are progressing and to record any failures. In late August, with the chicks still mostly fluffy but with dark adult feathers showing through, we go out and fit them all with unique identification rings. Before coming south the largest bird I'd ringed was a Greater Black-backed Gull. At the time that seemed pretty big, especially compared to the Willow Warblers and Chiffchaffs I was used to, but although the techniques are pretty similar there's some major differences in how to hold these birds.
Data retrieved from birds with rings, and more recently those carrying tiny geolocators, was told us all sort of information about their range, routes and feeding areas. It helps to know these things when trying to protect them and their key habitats.
|Engaging in some friendly chat with a healthy looking chick.|
|An unconventional approach to ringing. This strange position keeps the chicks passive and safe, allowing a quick squeeze to apply a unique ring.|
Around November, after about nine months on the nest, with the weather warming a little in the Antarctic spring the chicks start to fledge. By this time they've lost their down and have a complete covering of dark adult feathers. For a long time they get off the nests and walk around, investigating their surroundings. On windy days they'll hold out their wings, feeling the breeze rushing through their feathers and trying a bit of flapping, building up those flight muscles. This increases the older they get and late in the season you can see these huge birds facing into the strong winds, jumping and flapping, getting 6ft in the air but wobbling in a rather uncontrolled manner as they try to master the balance and timing it takes to move in a straight line. It takes a lot of practice to make flight as easy as the adults manage.
|An almost fully developed chick getting a visit from both parents. It's rare to see both adults together, particularly at this stage in the season when they are both continually heading out and returning with food.|
|Letting the breeze blow through your wings must be a great feeling.|
|Not far off departure, looking for a launch spot.|
Once they fledge the young will probably spend at least the next five years at sea before returning to their breeding sites, though they don't usually start mating and laying eggs until they are 10 - 15 years old. During this 'teenage' period they will follow the circumpolar winds and currents, travelling clockwise around the whole Antarctic continent. A successful pair will not breed for another year and instead will return to the ocean where they are most at home, soaring effortlessly over the waves on huge, unflapping wings.