ADU Projects and Research
 

News from the Colonies 1

Life and Times of the African Penguin

November 2007

1 November 2007    

Animals in zoos are ambassadors for their counterparts in the wild. The interviews below aim to connect the African Penguins in the zoo which you support with the African Penguins living in their colonies in South Africa and Namibia.
  Halifax Island Penguins There are 27 breeding colonies of the African Penguin in Namibia and South Africa. Halifax Island, where Jessica Kemper does her research, is a desert island a kilometer off the desert coastline. In common with most colonies on the offshore islands, guano scraping has taken the island down to bedrock. Penguins therefore nest in the open, where they are at the mercy of the heat and the Kelp Gulls
Wild African Penguins are in trouble. To find out more about what is going on the colonies, I talked to three penguin researchers. Professor Rob Crawford is a marine scientist with the South African government, with special responsibilities for the seabird populations and he keeps the big picture in mind. Lauren Waller works for CapeNature and is responsible for the management of Dyer Island, a small island close to the southernmost tip of Africa; Lauren is also a PhD student in the Avian Demography Unit. Dr Jessica Kemper did most of the fieldwork for her PhD on tiny Halifax Island off the coast of Namibia. While Rob deals with the big picture, Lauren and Jessica fill us in on the details at two breeding colonies.

This will be an occasional publication. Its format will vary, depending on how it is used. Feedback will be appreciated. If you have received this indirectly, please email me and ask to be put on the distribution list.

Les Underhill       
les.underhill@uct.ac.za    

The global scene - Professor Rob Crawford

Rob, what was the outcome of the African Penguin census in 2007? Was it up on last year's, and do you think that the downward trend of the past few years had been reversed?

African Penguins breed in three discrete regions: Namibia, South Africa's Western Cape and South Africa's Eastern Cape. In 2007, some 21 000 pairs of African Penguins bred in the Western Cape, very close to the number of pairs recorded in 2006. In 2007, only 6 000 pairs bred in the Eastern Cape compared to more than 11 000 in 2006, a worrying decrease. The global population attained its lowest recorded value of about 31 000 pairs in 2007. Unfortunately, the downward trend in African Penguins has continued, and it has certainly not been reversed.

In a nutshell, what are the key conservation issues facing African Penguins now?

At present, the main threat to African Penguins is a scarcity of food. The main food of African Penguins are two species of fish, anchovy and sardine. Both have been scarce for 25 years off Namibia. In the Western Cape, these fish have moved to the east and are out of range of the breeding colonies. While they are breeding, penguins cannot travel far in search of food. Recent studies with satellite tracking devices have shown that breeding penguins cannot search much farther than 20 km from their colonies for food. Once colonies become small, local factors can have a big impact, including predation and pollution. It is necessary to attempt to manage all these factors.

What are the important things we need to do now to help the population of penguins to increase?

  Black fronted African Penguin Every African Penguin has a unique pattern of black spots on its white front. This is an extremely unusual bird with a remarkably black front. (The first person to look at this picture said, "That penguin is oiled!" No, it isn't; those are all black feathers!) We see this penguin from time to time on Robben Island. In the next issue will describe a high-tech project that identifies individual African Penguins by their spot patterns
From a cold scientific viewpoint, a penguin population at a breeding colony will increase if the number of new breeders is larger than the number that die. We need to improve the birth rate and reduce the mortality rate. The number of young penguins produced per breeding attempt is on the low side, probably as a result of insufficient food. We think we can increase the amount of food around breeding colonies by creating "no fishing zones" around them. We are also attempting at present to raise the chicks orphaned or abandoned by their parents. Sometime in the future, it might be possible to use the chicks produced by penguins in zoos to bolster penguin populations at key colonies. We minimize mortality through removing predators that inflict too much damage, by reducing the likelihood of disease, by preventing oil spills and by rehabilitating birds that become oiled.

The view from Dyer Island - Lauren Waller

Lauren, as the 2007 breeding season draws to a close, has it been a productive year for the African Penguins on Dyer Island?

  Aerial view of Dyer Island Dyer Island. This peaceful scene is actually not a pretty sight. The little brown circles mark the breeding colonies of a diminishing population of African Penguins. Year by year, the circles get smaller, and many have disappeared. A happy picture of Dyer Island would show little greenery
No, it has not been a good year at all. We are very concerned about the numbers of African Penguins on the island. In 2006, there were 2057 breeding pairs and this has dropped further to 1513 in May 2007. In the 1970s, Dyer Island had about 25 000 pairs. This is a frightening decrease of 94% in only three decades.

This time last year, adults were deserting their chicks and going into moult. Is this year proving a more normal year?

This year is more normal in the sense that the adults are going into moult at the same time as they usually do. There are however still many really small downy chicks on the island. I saw five dead chicks when we surveyed the island on 27 October, but there are probably more because we could not get close to some of the breeding colonies due to the breeding Cape Cormorants, and some of the small chicks would be hidden in rocks and vegetation. Our most recent counts estimated that there were about 350 chicks, which is less than the 700 last year. It's difficult to tell which chicks are abandoned because they have formed close bunches or crèches of downy chicks, which makes it difficult to determine those that are not being fed. Some of these groups have up to 15 chicks. We send obviously abandoned chicks off to SANCCOB for rehabilitation.

We removed the first batch of 99 chicks from the island on 28 October and took them to SANCCOB. A further 28 were removed on 30 October. These were chicks which were visibly underweight, standing alone unattended by an adult, in big creches which were obviously not being fed by the one or two adults with them, or in among small groups of moulting adults. Most adult penguins on Dyer Island are now moulting; from past experience we know that even the apparently well fed chicks will at some point start losing condition. It is likely that several hundred more chicks will be sent to SANCCOB over the next few days.

SANCCOB has a remarkable success rate with rearing these chicks. Of the 694 chicks from Dyer Island which were reared in captivity at SANCCOB last year, 646 (93%) were released. Follow-up studies of these "orphaned chicks" reared and released in this way indicates that the rate at which they return to breed does not differ from that of naturally raised chicks.

  Three chicks on  Dyer Island The two chicks on the right are noticeably thinner than the chick on the left. Dyer Island, 26 October 2007
Have any of the chicks that were reared in captivity last year been seen yet? When do you expect to start seeing them?

We will only know the fruits of our efforts in a few years time, because we won't see them on Dyer Island for a few years. Once chicks fledge they leave their island, they spend the next few years swimming around the coastline and sometimes even "visiting" other colonies. After 3-4 years, they usually go back to the island where they hatched, and join the breeding population there.

What seabird species are breeding on the island now?

As the African Penguin breeding season on Dyer Island draws to a close in October, it's the turn of the Cape Cormorants. The first birds started to pair up in September, and the island is now covered with tightly packed colonies of Cape Cormorant nests. There are already some chicks that have hatched, and we expect the island to be full of juvenile Cape Cormorants in November/December.

The African Black Oystercatchers will also be breeding soon. There are normally about 22 pairs on the island and we'll be starting to monitor their breeding from November.

With all this activity and extra food source, Kelp Gulls have also started to lay their eggs. Ever the opportunist, they are quick to snatch an egg or chick from an unsuspecting Cormorant. They are also masterfully successful at mobbing adult and juvenile Cormorants, inducing them to regurgitate their latest meal!

A Namibian view - Dr Jessica Kemper

Jessica, how did the African Penguins on Halifax Island fare in 2007?

  Thin Halifax Island penguin chick "... about 80% of the 300 chicks present that day (including 127 fully feathered chicks) were in poor condition ..." Here is one of them
So far not all that well. Even though lots of chicks hatched between June and August, the Halifax Island penguins were hit by a food shortage just when the chicks were about half-grown. On my last visit to Halifax Island, on 26 September 2007, I counted 42 dead chicks, ranging from one month old chicks to fledglings (about three months old). All had died from starvation. This is by far the highest number of starvation mortalities I have encountered at Halifax Island in the eight years of doing field work there. About 80% of the 300 chicks present that day (including 127 fully feathered chicks) were in poor condition. I even saw four fully feathered but malnourished chicks standing on the beach, attempting to go to sea for the first time; it is highly unlikely that they will survive their first few days at sea in that condition.

This apparent food shortage seems to be quite widespread, because during the same week there were similar reports from three other islands in Namibia (along 150 km of coastline) - unusually high numbers of chick mortalities from starvation. Luckily this shortage does not seem to have affected any adults so far. During the first week of October, staff at Mercury Island noted that penguins were arriving back at the island with full bellies and that the chicks were already looking better! Let's hope that this food will soon also become available farther south to the Halifax penguins.

How many penguins do you currently have breeding on Halifax Island?

It is difficult to estimate the breeding population on Halifax Island because the breeding season extends almost all year round, and we suspect that quite a few of them breed more than once a year, while others may skip breeding altogether. We count all nests (containing eggs or chicks) once a month to get an idea of numbers of penguins breeding throughout the year. During peak breeding activities, when we assume that most pairs will breed, we have counted as many as 670 nests during the last decade. This year, we counted 530 nests in August and are hoping for another, perhaps bigger, wave of nests being initiated during December and January, if feeding conditions around the island improve.

What has been the trend in population numbers on Halifax Island in recent years and how does this compare with the other breeding colonies in southern Namibia?

  Halifax Island 1930s This photograph was probably taken in 1939. Jessica Kemper found it in the Eberlanz Museum, in Lüderitz. It was taken from the northern end of Halifax towards the centre. We are grateful to the museum for allowing us to use this picture, so that we can compare it with ...
  Halifax Island 2004 ... the identical view in August 2004. This is a time of the year when there ought to be lots of penguins breeding. Notice how the last of the guano has been removed down to bedrock
Penguin numbers on Halifax Island, both in terms of individuals in adult plumage and nests, have been increasing steadily by between 5-9% per year over the last decade. It seems that Halifax Island is sought after property for young penguins from elsewhere, particularly for those originating from Possession Island, 45 km to the south of Halifax Island. We know this from re-sighting records of penguins which have been banded before fledging. These penguins may only visit for short periods, but some of them have permanently settled on Halifax Island.

Halifax Island is the only one of the four main breeding colony of African Penguins in Namibia where numbers are increasing (the other three colonies being Mercury, Ichaboe and Possession Islands; together these four islands account for about 96% of the Namibian penguin population). Although it is not clear why Halifax Island should be faring so much better, possible contributing factors to the declining population trend at the other three islands are likely to be the severe lack of food around Possession Island, where penguin diet is dominated by fish larvae and cephalopods, and a combination of poor food availability, competition for quality food (and possibly nesting space) with other seabirds, disturbance and seal predation on Mercury and Ichaboe Islands.

What are the biggest problems facing penguins in your area, and can anything be done to help solve them?

The main problem appears to be the availability of reliable, good quality food. The main prey of most penguins in Namibia is Pelagic Goby (at least north of Possession Island), which is far less palatable and nutritious compared to sardine and anchovy, their preferred food and the main prey of African Penguins in South Africa. Gobies are also more tricky to catch as they do not readily form shoals and tend to be demersal. After being heavily overfished during the 1960s and 1970s, the remaining sardine and anchovy stocks are now concentrated in central and northern Namibia and are generally not available to breeding Halifax penguins.

Breeding success is particularly poor on Halifax Island. Most of the penguins on Halifax Island nest on the surface, because the cement-like guano layer they used to burrow into got removed and sold as fertilizer until the early 1970s. Nesting on the surface exposes eggs and chicks to marauding Kelp Gulls. Large downy penguin chicks in surface nests are particularly vulnerable to heat exhaustion on Halifax Island, where air temperatures can occasionally exceed 35ºC (88ºF). In 2001 we attempted to improve breeding success by providing the Halifax penguins with artificial shelters. This strategy seems to work, with the penguins readily taking to their new accommodation and with breeding success of nests in shelters significantly higher than that of surface nests. I just wish that the shelter-breeding penguins would look after their shelters a little bit better and not cram them full of nesting material (mainly seaweed, shells and rocks) to the extent that they no longer fit inside!

What other seabird species are breeding on Halifax Island at present?

  Swift Terns bringing anchovy to their chicks "The Swift Terns fledged hundreds of chicks, just at a time when shoals of perfectly-sized sardine and anchovy paid a brief surprise visit to the vicinity of the island"
Halifax Island has a relatively large Kelp Gull population, with up to 350 breeding pairs - a lot for a 10 ha island. They are quite a nuisance, because they are experts at stealing poorly guarded penguin eggs and even chicks up to about 800 g. About 80 pairs of Crowned Cormorants and 20 pairs of African Black Oystercatchers also nest on the island. This year we had a colony of Swift Terns (about 1 000 pairs) and Hartlaub's Gulls (70 pairs) nesting simultaneously on Halifax Island for the first time since the 1980s. For two months the normally fairly tranquil island turned into an incredibly noisy, bustling place. Not that the penguins seemed to mind. It is likely that the terns and gulls were those which used to nest next to Lüderitz harbour, about 10 km to the east of Halifax Island (as the tern flies), but after the harbour got expanded and private houses (complete with domestic cats) were built next to their traditional breeding sites during the late 1990s, they had stopped breeding there. They certainly made a great decision to move to Halifax Island, where they were able to breed in peace. They fledged hundreds of chicks, just at a time when shoals of perfectly-sized sardine and anchovy paid a brief surprise visit to the vicinity of the island.

What can you do to help the penguins along the coastline of southern Africa? You can, through your zoo, purchase an artificial nest box, so the penguins can get underground, out of the sun and safe from predators. You can, through your zoo, make a donation to support one of the projects doing conservation research for African Penguins. You can also help to support the rearing of the current batch of abandoned chicks at SANCCOB.

 

ADU Web Page http://www.aviandemographyunit.org