Notas Breves POST-FLEDGING DISPERSAL OF SOUTHERN GIANT PETRELS MACRONECTES GIGANTEUS FROM NORTH PATAGONIAN COLONIES

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1 Notas Breves POST-FLEDGING DISPERSAL OF SOUTHERN GIANT PETRELS MACRONECTES GIGANTEUS FROM NORTH PATAGONIAN COLONIES DISPERSIÓN DE JUVENILES EMANCIPADOS DE PETREL GIGANTE DEL SUR MACRONECTES GIGANTEUS DE COLONIAS DEL NORTE DE LA PATAGONIA Sofía COPELLO* 1, Fabián RABUFETTI** and Flavio QUINTANA* *** The southern giant petrel, Macronectes giganteus, is a procellariform with a global population of about 55,000 breeding pairs distributed in 129 colonies in the southern oceans (ATCM, 2008). It is considered a Near Threatened species under the International Union for the Conservation of Nature (IUCN) criteria (BirdLife-International, 2008) and recently, the Scientific Committee on Antarctic Research (SCAR) suggested to downgrade considered the status of the Antarctic population to Of Least Concern (ATCM, 2008) as new population data indicated that the global population was significantly larger than when the original IUCN listing was proposed. The southern giant petrel is one of the 27 procellariformes listed under the international Agreement on the Conservation of Albatrosses and Petrels (ACAP) and has been included as a Threatened species in the Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), see: The Advisory Committee of ACAP has identified the need to fill information gaps on the at-sea distribution of southern giant petrels and other listed species. Data of the at-sea distribution of adults and juvenile dispersion strongly contribute to the design of coastal and pelagic marine protected areas, and are an essential step for the conservation of procellariform species. Traditionally, seabird dispersal has been studied from sightings at sea by observers aboard vessels. This methodology is of limited value because the origin, sex and age of birds remain unknown. Nowadays, remote tracking of southern giant petrels (González-Solís et al., 2000; Quintana and Dell' Arciprete, 2002; Gonzaléz- Solís et al., 2008) and other procellariformes (see review Birdlife-International, 2004) provide accurate information on at-sea distribu- * Centro Nacional Patagónico (CONICET), Boulevard Brown S/N, (U9120ACF) Puerto Madryn, Argentina. ** Aves Argentinas/BirdLife, Matheu 1246/8, (C1249AAB) Buenos Aires, Argentina. *** Wildlife Conservation Society, New York, NY 10460, USA. 1 Corresponding author: scopello@cenpat.edu.ar

2 104 COPELLO, S., RABUFETTI, F. and QUINTANA, F. tion and bypass the shortcomings of ship-based observations. However, the understanding of animal movements can be complemented by banding studies. This less expensive approach is also useful for the examination of marine habitat use at a broader scale. Also, as banding results are based on a large number of individuals, they are also helpful for determining population parameters in long term studies. There is currently no information about the at-sea movements of juvenile southern giant petrels from Patagonian colonies. Linked with information from satellite tracked southern giant petrels from the same colonies (Quintana and Dell' Arciprete, 2002; Quintana and Copello, unpubl. data), data gathered in this study, will help to determine pelagic areas at-sea of particular importance for southern giant petrels, including contributing to marine Important Bird Areas (IBA, and other designations relevant to conservation and management of marine habitats. This approach is also very relevant to assessing the threats faced at-sea by southern giant petrels. Here, the dispersal of the southern giant petrel fledglings from the Patagonian colonies of Argentina is characterised for the first time and the marine areas used during their first years of life evaluated. A total of 1,591 southern giant petrel fledglings were banded at Isla Arce (45º 00 S, 65º 29 W) and Gran Robredo (45º 08 S, 66º 04 W), Patagonia, Argentina (fig. 1) during breeding seasons. Approximately, 2,300 pairs breed annually at both islands (Quintana et al., 2006). Banding was carried out on ~ % of the chicks that fledged at Isla Arce ( breeding seasons) and % of the chicks from Isla Gran Robredo (2004 and 2005 breeding seasons). Fledglings were banded as late in the season as weather conditions permitted, usually in late March or early April, a couple of weeks before they left the colony (Quintana et al., 2005; Copello and Quintana, unpubl. data). The disturbance during this period is negligible given that parents were not present in the colonies and chicks were nearly fully grown and quite robust (Quintana et al., 2005; Copello et al., 2006). Most of the fledglings (71 %, n = 1126) were ringed with metal (stainless steel or aluminium, National Band and Tag Co., 22 size butt-end) and plastic color bands (Pro-Touch engraving, 40 mm high and 18 mm inside) on the left and the right leg, respectively. In 2002, twenty five birds (2 %) were banded only with metal rings and in 2004, 440 birds (28 %) only with plastic bands. Plastic bands had a three letter code with the following combination of colors: red with white letters (2001 and 2002), yellow with black letters (2003) and white with black letters (2004). Metal rings were numbered from AA001 to AA1650. The gender of each bird was determined using molecular techniques and/or discriminate function, following Copello et al., Petrel sightings were mapped using Arcview 3.2. Distances of the sightings from the eastern hemisphere were calculated using Distance and Bearing extension (with geodesic curves) and those from the western hemisphere, using Shape Geometry extension with a Gauss Kruger projection. Water depth at the position of each sighting was obtained from the GEBCO database (1 resolution) and from the National Geophysical Data Center ( (10 resolution) for the sights from the western and eastern hemispheres, respectively. A total of 63 banded juvenile southern giant petrels (~ 4.2 % of the total ringed birds) were sighted away from their colonies from July 2003 to January 2008 (table 1, fig. 1). Three birds were seen more than once, adding up to 67 sightings. The total recovery rate was comparatively high (4.2 %) and extremely variable between years (< %). Most of the records were of live birds (n = 51, 76 %) and 16 (24 %) of dead birds. Sixty nine percent of band recoveries from dead animals corresponded to birds younger than one year (table 1). Eighty four percent of living birds was re-

3 POST-FLEDGING DISPERSAL OF SOUTHERN GIANT PETRELS 105 FIG. 1. Locations of the southern giant petrel recoveries banded at North Patagonian colonies, Argentina. Black star indicates banding sites. Inset: South American locations. [Localización de los registros de petrel gigante del sur anillados en colonias del norte de la Patagonia, Argentina. Las estrellas negras indican las localidades de anillamiento. Recuadro: Localizaciones de registros en Sudamérica.] ported from commercial fishery vessels (table 1) although none of them were caught in fishing gear. These birds were mainly associated with trawlers (51 %), longliners (36 %) and a smaller proportion with jiggers and tourist vessels (< 11 %). Five birds were seen feeding on whale carrion at the Valdes Peninsula, Chubut, Argentina. Fifteen of the recovered birds were females, 19 males and 29 were of unknown sex (table 1). Two of the three birds sighted more than once were successively associated with fishing vessels and the third was seen from a longliner vessel as well as in his natal colony (Arce I.) (table 1). The age of the

4 106 COPELLO, S., RABUFETTI, F. and QUINTANA, F. TABLE 1 Band recovery data for southern giant petrels from North Patagonia colonies. Plastic band color in parentheses (Y = yellow, R = red, W = white). Banding colony: A = Arce, GR = Gran Robredo. Sex: M = male; F = female. Banded date Banded colony Plastic band Metalic band Sex Recovery location 15 March 2002 A ACY (R) AA040 M Argentina 15 March 2002 A ACY (R) AA040 M Argentina 24 February 2003 A AFR (R) AA090 M Uruguay 24 February 2003 A AFV (R) AA099 M Brazil 23 March 2004 A AAU (Y) AA158 F Argentina 23 March 2004 A AFT (Y) AA233 M Brazil 23 March 2004 A AND (Y) AA356 M Brazil 25 March 2004 GR AVE (Y) AA469 M New Zealand 25 March 2004 GR AVE (Y) AA469 M New Zealand 25 March 2004 GR AYD (Y) AA507 F Argentina 25 March 2004 GR CAF (Y) AA550 F Brazil 25 March 2004 GR CCK (Y) AA573 F Argentina 25 March 2004 GR CCK (Y) AA573 F Argentina 25 March 2004 GR CCK (Y) AA573 F Argentina 25 March 2004 GR CCP (Y) AA576 M Brazil 25 March 2004 GR CDD (Y) AA594 F Argentina 30 March 2005 GR ALY (W) AA657 M Uruguay 30 March 2005 GR AHE (W) AA763 M Argentina 29 March 2005 A DFS (W) - F Australia Metalic - Uruguay Metalic - Uruguay - - (R) - - Uruguay - - (R) - - Uruguay Metalic - Uruguay 25 March (Y) - - Brazil 25 March (Y) - - Brazil 25 March (Y) - - Brazil 25 March (Y) - - Chile Metalic - Argentina 25 March (Y) - - Brazil

5 POST-FLEDGING DISPERSAL OF SOUTHERN GIANT PETRELS 107 TABLE 1 [Datos de los registros de petrel gigante del sur de las colonias del norte de la Patagonia. Color de las anillas de plástico entre paréntesis (Y = amarillo, R = rojo, W = blanco). Colonia de anillamiento: A = Arce, GR = Gran Robredo. Sexo: M = macho; F = hembra.] Recovery date Age (months) Distance (km) Condition of recovered Fishery 27 February alive yes 21 April alive no 13 October alive yes 18 July alive yes 29 May alive yes 11 October dead no 10 August dead no 03 March alive yes 07 April alive yes 13 October dead no 14 October dead no 09 February alive yes 22 February alive yes 23 February alive yes 05 June dead no 20 November alive yes 16 June dead no 29 May alive yes 28 May alive yes 29 September alive yes 4 October alive yes 10 October alive yes 15 October alive yes 20 October alive yes 16 May alive yes 19 May alive yes 07 January alive yes 10 January alive yes 07 August alive yes 16 July alive yes 02 July alive yes 16 July alive yes 15 July alive yes 21 July alive yes 02 July alive yes 24 September alive yes 01 September alive yes 09 December alive yes 30 March alive no 02 September alive yes

6 108 COPELLO, S., RABUFETTI, F. and QUINTANA, F. TABLE 1 CONT. Band recovery data for southern giant petrels from North Patagonia colonies. Plastic band color in parentheses (Y = yellow, R = red, W = white). Banding colony: A = Arce, GR = Gran Robredo. Sex: M = male; F = female. Banded date Banded colony Plastic band Metalic band Sex Recovery location 30 March (W) - - Uruguay 30 March 2005 GR AZN (W) AA1098 F Australia 30 March (W) - - Uruguay 23 March 2004 A AGA (Y) AA265 F Argentina 29 March 2005 A CKH (W) M Australia 30 March 2005 GR CXK (W) AA672 F Argentina 29 March 2005 A CTJ (W) - F Australia 15 March 2002 A ADS (R) AA049 - Argentina 30 March 2005 GR AXL (W) AA749 F Australia 25 March 2004 GR ATD (Y) AA440 M Uruguay 30 March 2005 GR ALE (W) AA652 F New Zealand 30 March 2005 GR ARA (W) AA1050 F Brazil 30 March (W) - - Argentina 30 March (W) - - Argentina 30 March 2005 GR AFL (W) AA1107 M Argentina 30 March 2005 GR ARY (W) AA1021 M Uruguay 24 February 2003 A AFZ (R) AA097 M Argentina 25 March 2004 GR CER (Y) AA624 M Argentina 29 March 2005 A DKC (W) - M Argentina 25 March 2004 GR CEZ (Y) AA617 M Argentina 30 March 2005 GR ARF (W) AA1007 M Australia 30 March (W) - - Argentina 30 March 2005 GR AVR (W) AA872 F Argentina 25 March 2004 GR AZD (Y) AA532 F Argentina 29 March 2005 A DDF (W) - M Australia bird at the recovery date could be determined for 55 of the 63 individual cases. Most of the recoveries were on first-year birds (67.3 %), 18.2 % corresponded to second-year birds, 10.9 % to third-year birds and the rest (4 %) were birds older than three years. The earliest sightings occurred at the age of about two months old (table 1). Juvenile southern giant petrels from Patagonia spread far across the southern oceans. All band recoveries occurred in the southern hemisphere, from 23 to 54 S (fig. 1). The most northerly recovery corresponded to a dead bird found in Ciudad de Imbiatuba, Santa Catarina State, Brasil (23 11 S) and the most southerly was a bird associated with a longline vessel at Burdwood Bank (54 40 S). The sightings covered the Southern Ocean from east to west (75 E W), with recaptures in the southwest Atlantic, southeast Indian and south

7 POST-FLEDGING DISPERSAL OF SOUTHERN GIANT PETRELS 109 TABLE 1 CONT. [Datos de los registros de petrel gigante del sur de las colonias del norte de la Patagonia. Color de las anillas de plástico entre paréntesis (Y = amarillo, R = rojo, W = blanco). Colonia de anillamiento: A = Arce, GR = Gran Robredo. Sexo: M = macho; F = hembra.] Recovery date Age (months) Distance (km) Condition of recovered Fishery 27 May alive yes 20 May dead no 25 July alive yes 03 November alive yes 24 July alive yes 30 July dead no 11 September dead no 19 July alive yes 01 August dead no 12 Dececmber dead no 22 October alive yes 20 January dead no 02 February alive yes 01 January alive no 08 March alive no 08 March alive no 25 December alive no 11 June dead no 25 December alive no 05 November alive yes 25 December alive no 18 July alive yes 01 September dead no 01 November alive yes 16 January dead no 31 October alive yes 03 June dead no Pacific Oceans. The eastern-most recovery was a bird associated with an artisanal longline vessel at Golfo de Penas in Chile (75 00 E), while the western-most sighting was made from a sailing boat at Kaikoura, New Zealand (174 5 W) (table 1, fig. 1). Most of the sightings were made in the waters of Argentina (52.2 %), followed by Uruguay (16.4 %), Brazil (14.9 %), and Australia and New Zealand (14.9 %). Only one bird was observed in Chile. Most of the sightings at sea (n = 44) were recorded in waters < 200 m (continental shelves, 54.5 %). However, some of them also came from shelf break areas (200-1,000 m, 34.1 %) and the high seas (> 1,000 m, 11.4 %). The distances from colonies to the recovery locations were extremely variable with an average distance of 2,451 km (± 3,482, range 6-12,453 km). However, most of the records (83 %) were made < 3,500 km from the colony (table 1).

8 110 COPELLO, S., RABUFETTI, F. and QUINTANA, F. Juvenile southern giant petrels from the colonies in North Patagonian colonies were found over a vast area of the Southern Ocean. However, more than half of the banded birds were seen in waters off the Patagonian Shelf relatively close to their natal colonies. Satellite tracking data also revealed the extensive use of the Patagonian Shelf by adults and juveniles throughout the year (Quintana and Dell' Arciprete, 2002; Quintana and Copello, unpubl. data). Even during the post-fledging period, i.e. during the first months of their life, the birds widely used the Patagonian shelf, flying to the north along the shelf break and reaching Uruguayan and Brazilian waters (Quintana et. al., unpubl. data). Some of the banded birds from this study were also sighted far away from their natal colonies, in the Exclusive Economic Zones of neighboring countries such as Uruguay, Brazil and Chile. This pattern of dispersal was also reported for juvenile black-browed albatross (Thalassarche melanophris) from Malvinas/Falkland Islands (Sullivan, 2004). Remarkable was the high number of recoveries (n = 10) received from Australia and New Zealand marine areas, highlighting the extraordinary capacity of this species to reach distant locations, even during their first years of life. However, without telemetry evidence, it is not possible to determine if these species continued to fly east following the prevailing westerly winds. It is possible that they undertook a circumpolar migration, as has been suggested by several authors (Harrison, 1983; Hunter, 1984; Trivelpice and Trivelpice, 1998). Similarly to other banding studies in giant petrels (Hunter, 1984; Trivelpice and Trivelpice, 1998; Coria, unpubl. data; Patterson and Hunter, 2000), there were inter-annual variations in the recovery rate. However, the total recovery rate (4.2 %) is the highest reported for the species so far. The use of plastic bands which are clearly more visible than the conventional metal bands, could partially explain the high recovery rate in this study. It is well-known that seabirds are threatened by fisheries all around the world, and that incidental capture is the main cause of decrease in several populations (Tasker et al., 2000). The results given here indicate that most of the banded juvenile southern giant petrels were seen following trawlers and other fishing vessels. Previous studies reported adults and juveniles as ship-followers, generally associated with the longline and trawler fleets of the Patagonian Shelf (Favero et al., 2003; González Zevallos and Yorio, 2006; Sullivan et al., 2006) and in other areas of the Southern Ocean (Weimerskirch et al., 2000; Moreno et al., 2006). The relationship between fisheries and southern giant petrels from Patagonia was previously based on indirect evidence such as fishery related items found in diet samples (Copello and Quintana, 2003; Copello et al., 2008) and the overlap between at-sea distribution of tracked birds and fishing areas (Copello and Quintana unpubl. data). Although at-sea re-sighting can be overestimated, the large number of banded birds seen from these fleets highlighted the association between seabirds and fisheries. As suggested, the southern giant petrels can take advantage of such interaction through the use of the discards and/or marine debris (Copello and Quintana, 2003; Copello et al., 2008). The use of discards has been suggested as one of the factors responsible for the increase of the southern giant petrel population in the northern colonies of Patagonia (Quintana et al., 2006) and in the Malvinas/Falklands Islands (Reid and Huin, 2008). This is the first study reporting on the postfledging dispersal of juvenile southern giant petrels from Patagonian colonies. These results complement the existing satellite telemetry studies on at-sea distribution of the species in the south west Atlantic region (González-Solís et al., 2000; Quintana and Dell' Arciprete, 2002; González-Solís and Croxall, 2005; Quintana et al., 2005; Quintana and Copello, unpubl. data; Gonzaléz-Solís et al., 2008) and contribute to develop conservation and manage-

9 POST-FLEDGING DISPERSAL OF SOUTHERN GIANT PETRELS 111 ment plans for the species as well as the marine ecosystem they use. In particular, these data offer additional information for the development of criteria defining Important Bird Areas (IBA) at sea and/or high seas Marine Protected Areas (MPA). The data also identify areas of potential conflict between seabirds and fisheries. Finally, these data reinforce the importance of the Patagonian Shelf as migration and feeding habitat for southern giant petrels and other procellariforms species of the world. This marine ecosystem is considered of global relevance given that it sustains many top predator populations breeding in Patagonia as well as those from more distant regions (Croxall and Wood, 2002, These results also remark the importance of national and international research-based conservation programs to understand the at-sea threats of this and other wandering seabirds of the southern oceans. RESUMEN. El petrel gigante del sur es un procelariforme considerado Cercano a la Amenaza según criterios de la UICN. Para estudiar la dispersión de juveniles de esta especie en las colonias del norte de la Patagonia, Argentina, se anillaron individuos durante las temporadas reproductivas 2001 a Se registraron un total de 63 juveniles que se dispersaron ampliamente en los océanos del sur durante sus primeros años de vida, distribuyéndose sobre la Plataforma Patagónica, como así también en aguas distantes de Australia y Nueva Zelanda. ACKNOWLEDGEMENTS. We thank all banders and people who supplied recovery data for this study. We are grateful to Averaves-Uruguay for adding a link in their website with information about the Southern Giant Petrel Banding Campaign. Wildlife Conservation Society, Agencia Nacional de Promoción Científica y Tecnológica, Consejo Nacional de Investigaciones Científicas y Técnicas and Vogelbescherming Nederland (BirdLife Holland) financial support for this study. Centro Nacional Patagónico provided institutional support. We express our gratitude to three anonymous reviewers for their valuable comments on the manuscript. BIBLIOGRAPHY ATCM Status of the Regional, Antarctic Population of the Southern Giant Petrel- Progress, p. 6. SCAR. BIRDLIFE-INTERNATIONAL Tracking ocean wanderers: the global distribution of albatrosses and petrels. Results from the Global Procellariiform Tracking Workshop, 1-5 September, 2003, Gordon's Bay, South Africa. Birdlife International, Cambridge. BIRDLIFE-INTERNATIONAL Macronectes giganteus. IUCN IUCN Red List of Threatened Species. IUCN. COPELLO, S. and QUINTANA, F Marine debris ingestion by Southern Giant Petrels and its potential relationships with fisheries in the Southern Atlantic Ocean. Marine Pollution Bulletin, 46: COPELLO, S., QUINTANA, F. and SOMOZA, G Sex determination and sexual size-dimorphism in Southern Giant-Petrels (Macronectes giganteus) from Patagonia, Argentina. Emu, 106: COPELLO, S., QUINTANA, F. and PÉREZ, F The diet of the Southern Giant Petrel in Patagonia: fishery-related items and natural prey. Endangered Species Research, 6: CROXALL, J. P. and WOOD, A. G The Importance of the Patagonian Shelf for top predator species breeding at South Georgia. Aquatic Conservation: Marine and Freshwater Ecosystems, 12: FAVERO, M., KHATCHIKIAN, C. E., ARIAS, A., SILVA- RODRIGUEZ, M. P. and MARIANO-JELICICH, R Estimates of seabird by-catch along the Patagonian Shelf by Argentine longline fishing vessels, Bird Conservation International, 13: GONZALÉZ-SOLÍS, J., CROXALL, J. P. and AFANASYEV, V Offshore spatial segregation in giant petrels Macronectes spp.: differences between species, sexes and seasons. Aquatic Conserva-

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