The Bird’s Eye View of the BFAL’s Physiology

Black footed Albatross (BFAL) is one of the most magnificent birds to come across if you ever get on a boat to explore the Pacific’s open water. Its wingspan is greater than that of a hawk’s. You will be blown away by its black sleek silhouette rising from just above the waves then soaring high into a gale. It definitely does not live like our familiar sparrow neighbors. We’d better explore what makes this amazing bird the Black-Footed Albatross.

The BFAL has the body length of 64-74 cm and the wingspan of 193-219 cm. The weight ranges from 2.2-4.3 kg (Cornell University, 2017). The black bills with white root and black foot + overall dark brown to grey plumage make this bird relatively easily recognizable from other albatrosses like Laysan Albatross.

If you live in Nanaimo-Parksville area, then you’ll almost never see a BFAL because it is found in marine saltwater environments miles offshore. Its range is extensive as it covers most of the Pacific Northern Hemisphere and parts of the southern; however, most of these birds travel to their breeding grounds; Hawaiian Islands and the small islands off the coast of Eastern Asia (Canada, 2017).

Its average lifespan is about 12-45 years (Cornell University, 2017). Due to the declined population by the cruel human activities in the past decades, IUCN used to categorize the BFAL as “endangered”. However due to the protection efforts, it happily got bumped up to the “near threatened” category in 2018 and numbers are increasing each year, great news! (Avibase, 2019).

Unlike similar sized birds, like the Bald Eagle, BFAL is not quite a vicious aerial hunter nor even an underwater pursuer like a penguin. In the wild, it is mostly the scavenger of the sea (Anderson et al, 2000). It most actively forages during night or early in the morning, looking for prey or floating food near the surface and scoops food out of the shallow water. Its diet consists of fish, fish eggs, squid, crustaceans, and jellyfish (Harrison et at, 1983).

Flying fish spawn on floating debris in a big frenzy, making a big floating mass of their eggs. These eggs are a major part of the BFAL diet and the main staple for fledging chicks during breeding (Harrison et at, 1983).

The BFAL is also seen looking for fish caught in a ship’s wake or squids attracted to the lights of a boat (Anderson et al, 2000). Overall, its peaceful look reflects its attitude.

Breeding and Migration

Breeding of the BFAL begins in November. The BFALs have a courtship ritual of an almost “Spanish Flamenco dance”-like behavior often termed “clattering”. This behavior involves the couple crackling their bills at each other like Castanets followed by a dance that resembles a coupled ballet.

The female can only lay a single egg each year, and the egg hatches in January. The parents take turns in feeding the chick as one looks after it at the nesting sight and the other forages for a period of time to feed and bring back food for the chick. The chick fledges in June-July, and takes about 5-7 years to reach sexual maturity and to gain the full adult plumage (VanderWerf et al, 2019).

After leaving the breeding colony on land in July, the BFAL migrates all across the pelagic waters of the North Pacific for foraging, never to touch the land until next November. Many BFALs migrate around the North Pacific and some of them even reach the Bering Sea up north and the Galapagos Islands in the southern hemisphere (Kentaro et al, 2019).

Towards November, the BFAL will once again migrate back to its home breeding colony to mate. The just-fledged young birds will never set their black feet on the land for the first three years. The birds age four or over begin to come back to the breeding colonies on the islands, but do not nest or mate until they reach sexual maturity (VanderWerf et al, 2019).

The Flight

An Albatross including the BFAL uses its efficient wing design for two special flight skills to greatly boost its mileage. Flapping the wings for propulsion is too energetically costly in covering a long distance. Therefore it relies on wind to build a necessary amount of airspeed over its long, efficient wings to create lift. The lift created from facing the wings into the wind will push the bird up in the sky, and the bird can glide down to the direction where it wants to go, building more airspeed as it descends. Then it will pitch up and use this built up speed again for gaining altitude. This is the “Dynamic Soaring”, the primary skill that the albatross uses to fly.

And to further increase the efficiency, the BFAL greatly exploits the wind deflected upward by the ocean waves. And this is called the “Slope Soaring” (or sometimes included as a part of the Dynamic Soaring). If these two cycles are repeated, an albatross can travel up to 1000km/day without even once flapping! (Brooke, 2006)

The problem with this method is that they have a hard time taking off or staying airborne without wind. And flapping to build enough speed for a takeoff requires a painstakingly long takeoff run. When the wind is under ~18km/h speed, they are forced to stay on water (National Marine Sanctuaries, 2017). So you may have seen this bird flying like a pilot with 10000 hours of flying, but their true character is actually a sailor.

Multi-Purpose Nose

Aside from long-distance flight, the BFAL has a keen sense of smell to detect food. Their flight in the wind helps find food better as the wind carries the scent of food a long distance. The BFAL has a habit of chasing plankton bloom where there is a presumably higher chance of finding easy prey at the surface (Freedberg, 2018). Albatrosses are one of the few bird species with a keen sense of smell which enables them to detect food from 20 km away (Anderson, 2008). Sadly, some plastic debris covered in adhering photosynthetic plankton develop the same scent as BFAL’s food. It is suggested that this has been contributing to the BFAL’s ongoing plastic ingestion issue.

The BFAL drinks seawater when thirsty. To prevent up-taking excess amounts of salt and to obtain relatively pure water, it has well-developed salt glands just above the eyes. It is believed that excess salt is extracted in this organ and deposited from the nostrils via ducts connecting them (Freedberg, 2018).

As mentioned previously, wind and airspeed are critical for the flying sailor BFAL. They need to detect and measure the wind. Therefore, albatross’s nostrils are tubed and protrude out of the bills slightly. This allows the albatross to collect the airflow and sensitively measure its speed and direction via the air pressure inside. It is believed that the nasal canal is lined with pressure sensitive nerves (Freedberg, 2018). Humans invented “pitot tubes” almost exactly replicating the albatross’s tube nose thousands years after the albatross evolved to have this feature, and stuck them on almost every aircraft to measure its flying airspeed too.

Precious Fat

The BFAL has a specially modified proventriculus that produces stomach oil consisting of wax esters and triglycerides from the digested lipids. When a parent bird comes back to feed the chick after foraging, it regurgitates the fish and squids mixed with this nutrition-rich fatty material. During the period of a parent catching food for the chick, the chick relies on this cache of fat for growth and survival (Cornell University, 2008). Also this material has a very unpleasant odor which solidifies when spit out to the open air. In some conditions albatrosses use it to turn the predators away (Warham, 1976). For parents, it’s a race of getting their child as fat as possible for the upcoming flight lessons paid only by the student fat loan.

Research: The Black-Footed Albatross’s Decisive Breeding and Molting Strategy

Molting brings the everlasting beauty of birds. Unlike a live skin, a bird feather is a keratin-based dead structure which lacks its ability to maintain and repair itself. Therefore every bird must periodically shed all of their old worn feathers and regrow them through a process called molting. The Audubon society states that molting is essential for maintaining hygiene, color, shape, aerodynamic cleanness, and display of annual reproductive readiness (Jaramillo, 2019)

A normal bird goes through this expensive renovation of the feathers every year. However, the Black-Footed Albatross makes an exception. The BFAL is known to replace the partial sets of its feathers in each year known as incomplete molting, taking more than 2 years to overhaul its feathers.

BFAL’s unique partial molting pattern is most noticeable in the primaries. During the molting, ten primaries are often subdivided in outermost and innermost groups that molt in opposite directions (Langston et al, 1995) and this may mark a measure for how far the bird is into molting.

A team from the University of Washington hypothesized that the BFAL’s energetically expensive molting sequence may be influenced by another equally-expensive reproduction in a form of resource allocation (Rohwer et al, 2011).

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Study Method

The team conducted an observation-based study on the possible relationships between molting pattern and breeding years. The study chose Tern Island in the French Frigate Shoals in two different breeding years of 1998-1999 and 1999-2000 (Rohwer et al, 2011).

To analyze any existence of correlation in molting and reproduction, the study collected data from the actively breeding pairs for 1) age and numbers of the primary feathers replaced and 2) time invested in breeding (“small” for individuals failed in incubation or rearing the chicks early and “large” for individuals that succeeded in fledging or failed in the late rearing). The BFALs that use this location as its home breeding colony have been precisely banded since 1981 to help easily track the ages of the observed birds.

Outcome and Discussion

The team’s analysis found that BFAL replaces the three outermost primaries (P8-10) annually, and the remaining inner primaries (P1-7) undergo intrinsic biannual molting cycle. The 229 adults of even years of age (6, 8, or 10 … years old) replaced average of 4.93 (+_0.103) of their 10 primaries and the 219 adults of odd years of age replaced average of 8.62 (+_ 0.110) of their 10 primaries. In younger year birds especially showed the replacement of P8-10 only in even years, and P8-10 and P1-7 replacements in odd years. Also in some cases, P6-7 which get replaced in the odd year did not molt and went into the third year of use (Rohwer et al, 2011).

In the sampled breeding individuals of the odd age years (which the most of the primaries are replaced),   “large” individuals replaced average of 0.9 fewer primaries than the “small” with the more investment in the previous molting. And the about the same pattern is observed for the individuals of the even age years which the “large” individual had replaced fewer primaries than the “small” individuals (Rohwer et al, 2011). This might indicate that replacing all important feathers in one year might be a risky move because molting causes the bird to stay hungrier, decreasing the time and nutrient the chick is going to receive.

The investment spent in one year’s breeding had a significant effect on the likelihood of the bird’s return next breeding year. The individuals which spent “large” investment to the point of fully succeeding in chick fledging or failing late in chick rearing had significant less likelihood of returning to breed next year than the “small” individuals that failed early. The team suggests that individuals that spent large investment in breeding in the previous year are more aware of their need to molt next year. Because the worn feathers (especially the third years in use) greatly decrease the flight efficiency thus the foraging efficiency, the team suggests that skipping of breeding is driven by the need to avoid accumulation of worn feathers(Rohwer et al, 2011).

My Sincere Hope

Black-Footed Albatross is making a recovery from the past devastations such as the past habitat destruction and hunting, it iis classified in the “near-threatened” category facing new threats of pollution and longline fishing (Avibase, 2019). These results help uncover its reproductive cycle and help further assess their recovery rate. Further research with their resource allocation is highly desired for conducting a better restoration program. It is my sincere wish that our effort to understand them and protect them will become fruitful. One day, I would be greeted among the waves by a greatest echelon of happy-feeted Albatross, free of fishhooks and free of plastic.

Did you know……

Bill Nye, our science guy, is developing a scientifically accurate Albatross Flight Simulator! (the game features Short-Tailed Albatross but it’s still too cool to miss!)

References

Cornell University. 2017. Black-footed Albatross Identification. All About Birds, Cornell Lab of Ornithology. Available at: https://www.allaboutbirds.org/guide/Black-footed_Albatross/id.

Environment and Climate Change Canada. 2017. Management plan for the black-footed albatross (Phoebastria nigripes) in Canada. Species at Risk Act Management Plan Series iv(30). Available at: https://www.registrelep-sararegistry.gc.ca/virtual_sara/files/plans/mp_black-footed_albatross_e_proposed.pdf

Black-footed Albatross- Phoebastria nigripes. Avibase. Available at: https://avibase.bsc-eoc.org/species.jsp?avibaseid=EE8ECB1D8652F088.

Anderson, D. J & Fernandez, P, 2000. Nocturnal and Diurnal Foraging Activity of Hawaiian Albatrosses Detected with a New Immersion Monitor. The Condor 102, pp577–584.

Harrison, C. S & Hida, T. S. & Seki, M. P. 1983. Hawaiian Seabird Feeding Ecology. Wildlife Monographs 85, pp3–71.

VanderWerf, Eric & Young, Lindsay & Kohley, C. & Dalton, Megan & Fisher, Rachel & Fowlke, Leilani & Donohue, Sarah & Dittmar, Erika. 2019. Establishing Laysan and black-footed albatross breeding colonies using translocation and social attraction. Global Ecology and Conservation 19, e00667.

Kazama, K & Harada, T & Deguchi, T & Suzuki, H & Watanuki, Y. 2019. Foraging Behavior of Black-Footed Albatross Phoebastria nigripes Rearing Chicks on the Ogasawara Islands. Ornithological Science 18(1), pp27-37.

Hyrenbach, D & Dotson, R.C. 2001. Post-breeding movements of a male Black-footed Albatross Phoebastria nigripes. 29. pp7-10.

Brooke, M. 2006. Albatrosses and petrels across the world. Oxford Univ. Press.

National Ocean Service. 2017. Tracking Albatross Across the Pacific Ocean. National Marine Sanctuaries. Available at: https://sanctuaries.noaa.gov/news/features/0708albatross.html.

Freedberg, W. 2018. How Do Pelagic Birds Find Fresh Water at Sea?. Distractions Displays by Mass Audubon. Available at: https://blogs.massaudubon.org/distractiondisplays/how-do-pelagic-birds-find-fresh-water-at-sea/

Andersen, J. B. 2008. Albatrosses Follow Their Noses. Journal of Experimental Biology 211, pp4-4.

Awkerman, J & Anderson, D. J & Whittow, C. G. 2008. Black-footed Albatross. Cornell Lab of Ornithology; Birds of North America. Available at: https://birdsna.org/Species-Account/bna/species/bkfalb/introduction.

Warham, J. 1976. The Incidence, Function and ecological significance of petrel stomach oils. Proceedings of the New Zealand Ecological Society 24, pp84-93

Jaramillo, A. Understanding the Basics of Bird Molts. Audubon (2019). Available at: https://www.audubon.org/news/understanding-basics-bird-molts.

Langston, N. E. & Rohwer, S. 1995. Unusual Patterns of Incomplete Primary Molt in Laysan and Black-Footed Albatrosses. The Condor 97, pp1–19.

Rohwer, S., Viggiano, A. & Marzluff, J. M. (2011). Reciprocal Tradeoffs Between Molt and Breeding in Albatrosses. The Condor 113, pp61–71.