Falklands Conservation

Satellite tracking of the migration of Rockhopper Penguins breeding in the Falkland Islands during austral winter 2000.

In 1998, a 3-years study was launched to study the winter migration of Rockhopper Penguins breeding in the Falkland Islands, and in 2000 the third and final study period commenced. In late March 2000 seventeen Rockhopper Penguins from 3 different breeding colonies (Seal Bay, Sea Lion Island and Saunders Island) were successfully equipped at the end of their moult with satellite transmitters (PTT's) using the method described by Wilson et al. (1997). The PTT's were programmed to transmit for 8 hours every day and included a saltwater switch (SWS) to suppress transmission while underwater. The SWS can also be used to calculate the time spent underwater, i.e. the activity of the individual birds.

During the migration of the birds, all PTT's stopped transmitting after different time periods, which is likely to be due to a detachment of the units by the penguins. Overall, locations were received for periods of between 23 and 90 days. The results obtained contributed greatly to the valuable insights gained during previous investigations, and resulted in a comprehensive understanding of the winter foraging patterns of Rockhopper Penguins breeding in the Falkland Islands. Generally, as in previous years, the movements of the birds did not follow a clear pattern and were characterised by large individual, spatial and temporal variations.

At Sea Lion Island, 6 birds were equipped with PTTs and their movements subsequently tracked for an average of 62 ± 18.4 days. With a few exceptions, all birds remained in Falkland Islands' waters during the whole transmission period. Two birds travelled initially to the south, whereas two others circumnavigated the Falkland Islands westwards and eastwards, respectively. One bird remained all the time in inshore waters to the southeast of East Falklands. The PTT of the remaining bird was not functioning properly and delivered positions only accidentally. Consequently, the migration route of this particular bird could not be followed in detail. Positions, however, were obtained more than two months after equipment to the northwest of the Falklands.

Five birds were equipped with PTTs at a colony on Saunders Islands, and transmissions were received for an average of 80 ± 7.5 days. All five birds left Falkland Islands' waters during the first part of their winter migration and travelled westwards. Three Rockhopper Penguins arrived off the coast at Puerto Deseado, Argentina, where they stayed for several weeks. The transmissions of one bird ceased in this area. Of the two other birds, one then headed eastwards between 46' and 48'S, whereas the other continued to travel northwards. A comparable northward migration was shown by the two other birds that initially did not travel westwards to such an extent. The furthest position north, achieved by one bird, was 39.5'S.

The migration pattern of the six birds equipped at Seal Bay with PTTs was, with minor modifications, comparable to that displayed by the birds from Saunders Island. The average transmission duration was 76 ± 11.7 days. Four of the six birds headed west until they reached the South American mainland. However, whereas 3 birds then stayed close to Puerto Deseado, Argentina, one other travelled further south and remained in an area between 50'S and 52'S. The latter bird then returned in June into Falkland Islands' waters. The two other birds again migrated northwards, one finally reaching 41'S where transmission ceased.

In this study comprehensive insights into the winter migration of Rockhopper Penguins from the Falkland Islands were obtained. Obviously, there is a great variability in the winter migration, either seasonally and spatially. Furthermore, it became obvious that there is a large potential for Rockhopper Penguins to be impacted by oil exploration and exploitation activities in the northern as well as in the southwestern tranches. A more detailed analysis of all data collected during the past 3 years with special focus on individual, spatial and temporal variations of the migration patterns will be performed later this year.

Figure 1: Migrations of Rockhopper Penguins from Saunders Island (Click for larger version in new window)	Figure 2: Migrations of Rockhopper Penguins from Seal Bay (Click for larger version in new window)
Figure 3: Migrations of Rockhopper Penguins from Sea Lion Island (Click for larger version in new window)

Literature cited
R.P. Wilson, K. Putz, G. Peters, B. Culik, J.A. Scolaro, J.-B. Charrassin & Y. Ropert-Coudert (1997)
Long-term attachment of transmitting and recording devices to penguins and other seabirds.
Wildlife Society Bulletin 25: pages 101-106

Klemens Putz
Falklands Conservation

• Return to Penguin Projects?
• Contact us?
• Return to Index?