Hand-reared Penguin Plots Historic Course

Jul 06 2011

Richard Sherley1 and Venessa Strauss2
1Animal Demography Unit; 2SANCCOB

The Full Story:

The African Penguin population in South Africa has undergone a dramatic and sustained decrease within the last decade (Crawford et al. 2011). One of the postulated causes of this decline is a mismatch between the locations of breeding colonies in the Western Cape and the availability of the sardines and anchovies on which these Endangered birds feed (Crawford et al. 2008). Penguins must deliver food to their chicks in the nest to ensure that they fledge successfully. Because they cannot fly, they are limited in how far they can travel to find food; about 20–30 km from their colony (Petersen et al. 2006). For this reason, during the breeding season, they have little flexibility to change their behaviour in response to the whereabouts of their prey, but the adult sardine and anchovy have been breeding to the east of Cape Agulhas for at least the last 10 years (Roy et al. 2007, Coetzee et al. 2008). This is too far for a breeding African Penguin to swim.

African Penguin guarding chicks
Richard Sherley
An African Penguin guarding chicks on Robben Island in 2008. When feeding chicks, penguins are constrained in how far they can travel to find food as they must return before the chicks starve. This adult was fitted with flipper band A3335 after the Treasure oil spill. It was one of around 19,000 penguins translocated to Port Elizabeth in 2000. It swam the 800 km or so back to breed on Robben Island in subsequent years.

Juvenile birds, that have yet to start breeding, are theoretically free to move to areas where resources are more plentiful and they may travel considerable distances from the colony at which they were reared (Whittington et al. 2005b). In the past three decades, African Penguins have started breeding at three new mainland sites and re-colonised one former breeding site in response to changes in the local or regional availability of their prey (e.g. Crawford et al. 2001). Based on this knowledge, it has been proposed to initiate and protect a new mainland breeding colony closer to the current central mass of the fish stocks on South Africa's south coast.

As a result of the success of interventions to hand-rear and release chicks orphaned following the Apollo Sea and Treasure oil spills of 1994 and 2000 (Whittington 2002; Barham et al. 2008), the Chick Bolstering Project (CBP) was initiated to investigate the possibility of using hand-reared chicks to bolster wild colonies. Annually SANCCOB hand rears hundreds of chicks in the Western Cape, mainly originating from colonies managed by CapeNature, after these birds have been abandoned by their moulting parents at the end of the breeding season (e.g. Parsons and Underhill 2005). The CBP aims to develop the capacity and knowledge required to undertake the establishment of an entirely new African Penguin colony by developing the expertise necessary to hatch chicks from eggs in a hatchery housed at SANCCOB (to be functional in 2011) and by gaining an understanding of the mechanisms that lead fledglings to either return to the colonies at which they were hatched or to disperse to other sites as breeding adults. Unfortunately, large gaps exist in our knowledge of the period of the African Penguin life cycle from fledging until they return to breed at around three to four years old (Whittington et al. 2005a).

A study to address these gaps has been devised by researchers from the Animal Demography Unit (ADU) at the University of Cape Town, in collaboration with SANCCOB, the Department of Environmental Affairs (DEA), CapeNature and the Bristol Conservation and Science Foundation (BCSF). It will use a combination of data already available on the early part of the life-cycle (e.g. information from previous banding of chicks) and data obtained from tracking and ringing new cohorts of chicks to help understand how penguins select their breeding colony and how this decision may relate to the conditions they experience while they are in the nest as well as the conditions they experience while foraging at sea after fledging.

One of the main gaps in our knowledge pertains to the behaviour of these young birds at sea, where they go to find food and whether birds from colonies where numbers are stable and those where numbers are decreasing behave in the same way. Answering these vital questions is only possible by using remote sensing technologies like GPS loggers or satellite transmitters (also known as Platform Transmitter Terminals or PTTs), such as the one in the picture below. These kinds of devices have never been attached to juvenile African Penguins before, but the plight of the species now calls for a greater understanding of the pressures they face during the early part of their lives.

PTT device
Richard Sherley
One of the five PTTs to be deployed on hand-reared juvenile African Penguins. The devices were supplied by SirTrack, New Zealand, and linked to the Argos account at the Oceans and Coasts Branch of the Department of Environmental Affairs, South Africa.

To minimise the potential for negative impacts on the birds from carrying the devices (e.g. Wilson et al. 2004), five hand-reared chicks will be selected for a pilot study during 2011. Hand-reared chicks are being used in the first instance because they have two advantages over naturally-reared chicks at the point of release. First, they are invariably released in excellent condition, at above the average fledging mass. Second, unlike naturally-reared fledglings, they have extensive swimming experience when they go to sea for the first time (Barham et al. 2008).

The first chick for deployment was selected by SANCCOB veterinarian Dr. Nola Parsons, who coordinates the project and oversees chick rearing at SANCCOB. Nola says "The chick was hatched from penguins of wild origin kept at SANCCOB and was hand reared at SANCCOB. This chick was the first suitable bird from this season's breeding, at the time of releasing the bird was 3 months which is normal fledging age, it also met all standard SANCCOB release criteria which include, blood, weight and waterproofing evaluation".

The bird, designated 049 in SANCCOB's records and later dubbed "Lucy", was 3.2 kg when she was deemed ready for release - well above the weight at which most birds fledge in the wild, which is usually 2.2 to 2.8 kg (Sherley 2010). The device is attached to the feathers on the bird's back by a combination of a special tape and glue (some of the sequence is shown below).This approach has been used for many years to attach devices to seabirds for long periods (e.g. Wilson et al. 1997) and it is hoped that the PTT will stay attached for a maximum of six months using this method. Once the tape and glue wear off, the device will simply drop off. Hopefully, by that time we will have learnt some vital lessons about what these young birds do at sea. At worst case scenario, the device will drop off when the bird moults at around 18 months after deployment, but based on studies with these devices in the past, we don't expect the attachment method to last that long.

Fitting the PTT device
Richard Sherley and Carole Olivier (SANCCOB)
Bruce Dyer (Oceans and Coasts), Katta Ludynia (ADU) and Nicky Stander (SANCCOB) fitting the device to Lucy. The device is attached to the feathers on the back using tape and glue. First the feathers are lifted and tape is attached to the underside sticky side up (left hand insert), a small amount of super glue is spread on the feathers above the tape, the device is glued to the feathers and finally the tape is wrapped around the feathers to make a neat and secure package (right hand insert).

The device was attached at SANCCOB a few days before the bird was planned to be released so that it could swim at SANCCOB whilst wearing the PTT. The deployment was carried out by Bruce Dyer (Oceans and Coasts), Dr. Katta Ludynia (ADU) and Dr. Richard Sherley (ADU), who is heading the research component of the project. Attaching the device a few days before the bird was released gave Nola and the rest of the team some time to monitor its behaviour once equipped and gave the bird a chance to get used to swimming with the PTT onboard before it was let out into the ocean.

Lucy swimming at SANCCOB
Richard Sherley
Lucy swimming at SANCCOB 10 minutes after the devices was attached.

After a few days getting use to its new piece of hardware, Lucy was released on 26 June 2011 from a boat in Table Bay, just offshore of Robben Island. On this momentous occasion Nola said. “It is wonderful to release this bird which has the potential to give us so much more valuable information about movements of African penguin fledglings. This work is essential in improving the way in which we manage this Endangered species”.

Lucy swimming at sea Lucy released off a boat
SANCCOB
Lucy heading out into the open sea after being released off a boat close to Robben Island.

The PTTs are set up to relay positions from the Argos satellite system during the early hours of the morning, as we think that the birds will be on the surface during most of the hours of darkness. We hope to receive updates every other day, with our colleagues at Oceans and Coasts downloading the data through their Argos account. Lucy had been at sea for nine nights up to Tuesday (5 July 2011), when we got the last fix and by the end of her first night at sea, was already about 40 km offshore, just west of Robben Island in Table Bay. Since then the bird been more than 70 km out to sea, moving across an area of water over 200 metres deep. In total, the bird has moved about 430 km between being released on 26 June and her last known position in the early hours of the morning of 5 July, including a northward movement of 130 km in 48 hours. Flipper-banded juveniles from colonies in the Western Cape have been recorded moving in both an anti-clockwise direction towards the Eastern Cape and a clockwise direction towards Namibia and these juveniles have been seen at breeding colonies in Namibia (Whittington 2002), so she could be heading that way.

Map of Lucy's swim
Map by Mike Meyer, Oceans and Coasts Branch, Department of Environmental Affairs.
The movements of Lucy between 25 June 2011, when the bird was still at SANCCOB, and 5 July 2011, when the latest position was obtained. At the last position, Lucy had moved a total of 430 km since being released at 13h00 on 26 June 2011 and was over 160 km offshore.

To keep up to date on where the bird gets to in the coming months, keep an eye on Penguin Watch, where regular updates will be posted. For further information, please contact Venessa Strauss, CEO of SANCCOB (venessa@sanccob.co.za), or Richard Sherley (Richard.Sherley@uct.ac.za).

Official press release: PDF (262kb)

Acknowledgements:

The CBP is a collaboration between SANCCOB, the Bristol Conservation and Science Foundation, the Animal Demography Unit (University of Cape Town), the Department of Environmental Affairs (Oceans and Coasts), CapeNature, Robben Island Museum and the International Fund for Animal Welfare (IFAW). The project is made possible by the following sponsors: Zoo Basel; Zoo Leipzig; Living Coasts; Erlebnis Zoo Hannover; Dierenpark Amersfoort; Le Pal Nature Foundation; Allwetterzoo Muenster; ZOOM Torino; La Palmyre Zoo; Burgers Zoo; Georgia Aquarium; Leiden Conservation Foundation; National Aviary; Seaworld Animal Crisis Fund; Little Rock Zoo; Memphis Zoo; Steinhardt Aquarium; Toledo Zoo, Mystic Aquarium; Disney Rapid Relief Fund; Wallace Global Fund; Fort Wayne Kid's Zoo; and Jenkinson's Aquarium and Oceana. Mike Meyer, Rob Crawford and Bruce Dyer (Oceans and Coasts) are thanked for overseeing the logistics of setting up the devices on an Argos account and downloading the data.

References:

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Full article: PDF version (638kb)