ARTICLES ON HAWAIIAN BIRDS AND BIRDWATCHING AND OTHER PACIFIC WILDLIFE

Hawai'i's Albatrosses - The Black-footed Albatross

The Black-footed Albatross (Diomedia nigripes) is one of two species of Albatross that nests annually in the Hawaiian Islands, and one of three that occur regularly in the North Pacific (the other species being Laysan and Short-tailed Albatrosses). Although breeding birds are limited to the Northwest Chain and Lehua Rock, individuals can frequently be seen from the Main Island of Kaua'i and occasionally O'ahu and Hawai'i.

Black-footed Albatross is the second most numerous Albatross species in the North Pacific, although like all Albatross species here it's numbers have declined dramatically over the last one hundred years, much of this caused by exploitation, loss of nesting sites and accidental death from long-line fishing nets. Black-footed Albatross arrive on the nesting grounds in November and adults depart in the late spring, with juveniles departing by late June. Outside of the nesting period birds wander far and wide in the North Pacific and are only very occasionally found in the central Pacific during August and September, most birds having flown north from Hawai'i. A few small colonies also exist in Japan in the Senkakus, in the Bonins and on Torishima, in the Izu Islands.

Harrison (1990) states that "When two similar species feed offshore, as Laysan and Black-footed Albatrosses do, the birds that eat the most squid (Laysans) greatly outnumber their relatives. The ability or tendency to migrate also apparently influences population levels. Species that leave the Hawaiian archipelago during the non-breeding season tend to be more numerous than species that remain year round.

Figure 1. Distribution of Lausan and Black-footed Albatrosses in the North Pacific. From Seabirds of Hawaii by © C. Harrison (1990).

Note that Laysan Albatrosses tend to use the northwest Pacific and Black-footed Albatrosses tend to use the northeast Pacific.

Nesting

Black-footed Albatross nest on sandy beaches and seem to particularly like areas where it is exposed to wind-blown sand or open beach areas, whereas Laysan Albatross choose sites close to vegetation, which tend to be further away from the sea. This sometimes results in nests of Black-foots being washed away by high tides or waves in rough conditions. Most Laysan Albatrosses manage to find their way back to the island on which they were born, with only a few birds travelling to other areas; these "lost" birds however, may be the colonisers of new breeding grounds, helping the species to spread to other island-chains. The story is slightly different for Black-foots, which appear to have a much more keen sense of loyalty, with very few birds going to other areas. A good example of this is on Midway where Black-foots may be observed nesting in the middle of the island. This is due to military activity along the shoreline and reef which has modified the habitat, and so although the beach area is now perfect Albatross nesting ground, the birds use their traditional areas which are now some way from the beach. Some Albatrosses have been known to make the ocean crossing to their nesting grounds in astonishing time. Homing experiments in the Pacific have shown some birds to travel over 5,000 kilometres in just ten days to reach their nest!

During the nesting season birds return to their home island and reunite with their partner, which they usually pair with for life, which can be up to 28 years in the case of Black-foots. Elaborate displays and dances, accompanied by a range of whistling and whinnying sounds is carried out by adults when they return to strengthen their pair-bond and this may continue throughout the season. Most birds will not mate with any other partner, but in the incidence of death, or similar, birds will find a new partner. Occasionally Laysan and Black-foots will mate, resulting in hybrid young, which have a mix of characters. Laysan Albatrosses do not exhibit strong territorial behaviour and will only make bobbing and lunging motions to show where their nest site is, however once the chicks have hatched Black-footed Albatross may approach them and attack them quite ferociously, resulting in bloody patches on the necks of juveniles. Black-footed Albatross seem to be a little more temperamental about their nesting site.

After mating the adults return to sea for several weeks before returning to the nest site where the female lays the egg. Most Black-foots lay during the middle of November to late November, about ten days earlier than Laysan Albatrosses. Incubation lasts sixty-five days and during this time males may lose one-quarter of their weight, although it only takes a few weeks to regain what they have lost. Only one egg is laid and the parents take great care to look after it, after all it is a whole year until they will return and lay again. Albatrosses in Hawai'i tend to have a high fledgling rate, however, with two-thirds or more surviving in the Northwest Islands in most years. Care of the egg is very much alike in Laysan Albatross and has been covered in the Laysan Albatross account already.

Black-foot chicks start to hatch in mid-January. When a chick breaks the air space of its egg it starts to call and this results in a response by the adults to shorten their absences from the nest, so that they can feed the chick. For the first few days after hatching the chick is fed on stomach oil, which also helps the chick in the future to survive times when food is scarce or the adults are away from the nest for a long time. These oils also provide a source of water once metabolized - important when chicks may be left for several days in high temperatures on dry, sandy islands. Soon adults start to bring solid food, such as squid and flyingfish eggs. The energy requirement of the chick is greatest during the first few weeks after hatching, during which time one adult broods the chick and the other forages on the open ocean. Later when the chick can regulate its body temperature both parents are able to go to sea to hunt for food. During the heat of the day adults and chicks often sit back on their heels and spread their webbed feet to cool off. By mid-May the chick weighs about 3.2 kilograms, which is about 25 percent more than the adult male, although during the following few weeks they lose this weight, grow adult feathers and start exercising their wings in anticipation of leaving the nest. Gradually the parents stop attending the chick and the young bird is forced to go to sea and fend for itself. In total the chicks require about six months of attendance by the adults.

Once the bird leaves the safety of the island to feed it has many problems to face before it can return to find a mate in five or six years time. Tiger Sharks collect offshore during the summer to feed on the bumper crop of young, inexperienced Albatrosses and many die on their very first swim on the sea - seven or eight months care and attention gone in one bite. Once at sea the birds face other problems such as starvation, predation, poor weather and accidental killing by man, through ingestion of non-food items (such as plastic, rubber and metal) and through getting hooked on the hooks of long-line fishing nets, some of which are over one mile long.

Feeding

Black-footed Albatross feed by sitting on the water surface and catching prey just below or on the surface. They use their powerful bills to tear apart large prey such as squid, flying fish eggs and deep-water crustaceans, which float to the surface at night. Over 40% of their diet is made up of flying fish eggs of at least two species. Albatross eat eight squid families, although surface-dwelling flying squid species are the most common ones eaten. Black-foots eat half as much squid as Laysan Albatross, but Black-foots eat eleven times as many flyingfish eggs as Laysans. Laysans tend to feed at night and Black-foots tend to feed during the day, resulting in the difference in diets. This species often follows boats to pick food items from the disturbed water, although this habit also means that they often consume non-food items, such as plastic, rubber, sponges, paper and fishing line. Harrison (1990) states "The cool-water feeding locations imply that Hawaiian Albatrosses are actually temperate species that have a somewhat tenuous relationship with the tropical marine environment. Waved Albatrosses in the Galapagos are the only other tropical albatrosses. Like Hawaiian birds, waved albatrosses eat primarily squid, fish, and deep-water crustaceans. However, strategies in Hawaii and the Galapagos are similar, so dietary differences are probably due to local differences in prey species."

Black-footed and Laysan Albatrosses avoid competition not only by eating different prey species but also by feeding at different times. Many of the creatures taken by Laysans possess photophores which glow at night and Laysan's eyes possess high levels of rhodopsin, and thus enables them to feed during darkness. Black-foots lack this adaptation and therefore feed during the day on flyingfish eggs and flotsam.

The 15 million or so seabirds of Hawai'i consume over 400,000 metric tons of fish, squid, crustaceans and other food sources every year, of which Albatrosses and "Tuna birds" (Wedge-tailed Shearwaters, Sooty Terns, Christmas Shearwaters, Newell's Shearwaters, Brown and Black Noddies and White Terns), account for almost all the prey consumed - almost two-thirds. Along with Laysan Albatross, Bonin Petrel, Wedge-tailed Shearwater and Sooty Tern, Black-foots account for 94 per cent of the prey consumed.

Black-footed Albatross population estimates for Hawai'i.

Island Name	Numbers of pairs of Black-footed Albatross present
	(Number of Laysan Albatross in brackets)
Ni'ihau	40-60 (1-5)
Necker	200 - 250 (450 - 550)
French Frigate Shoals	4,000 - 4,500 (900 - 1000)
Gardner Pinnacles	0 (10 - 15)
Laysan	14,000 - 21,000 (105,000 - 132,000)
Lisianski	2,800 - 3,800 (23,000 - 30,000)
Pearl and Hermes Reef	8,000 - 11,000 (9,000 - 12,000)
Midway	6,500 - 7,500 (150,000 - 200,000)
Kure	700 - 1,300 (3,000 - 4,000)
Kaula	20 - 70 (25 - 70)
Ni'ihau	? (150 - 200)
Lehua	31 adults (50 adults)

All estimates from Harrison 1990, except Lehua estimate from Vanderwerf 2002. Note that Lehua refers to individuals, not pairs.

An interesting article on plumage variations and hybridization in Albatross was published in North American Birds in 2002 and is well worth checking out for details and photographs of Black-footed and Laysan Albatross hybrids. The full citation is:

McKEE, T. and P. PYLE. 2002. Plumage Variation and Hybridization in Black-footed and Laysan Albatrosses in North American Birds Volume 56:No.2. ABA, Colorado, U.S.A.

Watching Black-footed Albatross in Hawai'i

This species is far harder to see in the Hawaiian Islands than Laysan Albatross but can still be observed at several locations:

Midway: 6,500 to 8,000 pairs nest on the island and there is no difficulty seeing the species here.

NW Chain: As can be seen in the above table they are quite numerous on these islands, however there is strictly no access to these sites and so the average birder is unlikely to see them.

Lehua Rock: Located off the northeast side of Ni'ihau up to 20 pairs may nest each year and can be observed from snorkelling boats, whale-watching craft or fishing boats that sail from Kaua'i. On any one trip it is likely that only one or two birds may be seen (or none), as most birds will be out at sea collecting food for the chicks and so connecting with one of their visits is purely a matter of luck. there is no landing allowed on Lehua, which is a State Seabird Sanctuary.

Kaua'i: Although the occasional bird will land on the island (usually at either Barking Sands or Kilauea Point) most birds seen on Kaua'i are actually offshore. Most of the prominent headlands may provide a sighting, such as Ha'ena Point or Polihale, however the best "headlands" for this species are Kilauea Point and Ninini Point. Kilauea Point is encompassed in the Kilauea Point National Wildlife Refuge and has limited access, which is during the day, whereas most Black-foots seem to pass-by in the early evening. Having said that though, the species is quite regularly reported passing offshore during the day, although further out, and may be seen from nearby Hanalei Bay too. At Ninini Point, where Nawiliwili Lighthouse stands, the species sometimes passes close-by, although most are further out, with some right on the horizon. During the early spring of 1998 three birds flew right up to the Point and two actually flew around it before heading back out to sea!

O'ahu, Moloka'i, Lana'i and Hawai'i: The Black-footed Albatross is far less likely to be observed off these islands, simply due to the species breeding location, although the summering range tends to be more easterly for the species, and so one would perhaps expect it to be more commonly seen east of O'ahu. Any prominent headland might produce a sighting.

Weather conditions play a vital role in whether the birds pass close-by or out of view from land when going past the Main Islands. Winds from a northerly or north-easterly direction seem to produce more birds than winds from other directions. Late afternoon to early evening also appear to be more productive than morning or mid-day visits.

References

CULLINEY, J.L. 1988. Islands in a Far Sea: Nature and Man in Hawaii. San Francisco, Sierra Club Books.

DENNY, J. 1999. The Birds of Kaua'i. University of Hawai'i Press.

HARRISON, C.G. 1990. Seabirds of Hawai'i. Natural History and Conservation. Cornell University Press. New York.

HARRISON, P. 1983. Seabirds - An identification Guide. Helm, London.

HARRISON, P. 1987. Seabirds of the World. A photographic Guide. Christopher Helm, London.

HAWAI'I AUDUBON SOCIETY. 1997. Hawai'i's Birds. Regularly revised. Honolulu. Latest edition.

McKEE, T. and P. PYLE. 2002. Plumage Variation and Hybridization in Black-footed and Laysan Albatrosses in North American Birds Volume 56:No.2. ABA, Colorado, U.S.A.

MUNRO, G.C. 1960. Birds Of Hawai'i. Tuttle and Company, Rutland.

PRATT, H.D. , BRUNER, P.L. and BERRETT, D.G. et al. 1987. A Fieldguide to the Birds of Hawai'i and the Tropical Pacific. Princeton.

PRATT, H.D.. 1991. Enjoying Birds in Hawai'i - A Bird Finding Guide to the 50th State.

PRATT, H.D. and JEFFREY, J. 1996. A Pocket Guide to Hawai'i's Birds. Mutual Publishing Company.

SPEAR, L.B., AINLEY, D.G., NUR, N., and HOWELL, S.N.G. 1995. Population size and factors affecting at -sea distributions of four endangered procellariids in the tropical Pacific. Condor 97:613-638.

WILSON, S.B. and A.H. EVANS. 1890-1899. Aves Hawaiiensis: The Birds of the Sandwich Islands. London: R.H. Porter.

VANDERWERF, E. 2002. Notes on seabirds present on Lehua Rock in Spring 2002. Hawai'i Birding chatlist website communication.

Christian Melgar. Worthing, West Sussex, UK. 2002.

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