Birdwatch News Archive

An adult Hooded Grebe with some of this year's chicks. Photo: Pablo Hernandez (BirdLife International).

Early success for Hooded Grebe project

Posted on: 03 Jul 2012

BirdLife International's online appeal to save Argentina's Critically Endangered Hooded Grebe has already borne its first fruit, the charity says.

The appeal was launched in January this year as a new Preventing Extinctions Programme initiative. Hooded Grebe is endemic as a breeding species to Santa Cruz province in Southern Argentina, and is now so threatened it has been 'uplisted' to Critically Endangered in this year’s IUCN Red List update.

Previous research has identified that the main threats to Hooded Grebe are nest predation by an increasing population of Kelp Gulls, predation of adults by introduced American Mink, predation and competition for food resources from alien Rainbow Trout, loss of breeding sites through sedimentation as a result of land erosion caused by overgrazing, and breeding failure, due to increasingly strong winds, that detach floating nests from their moorings.

Urgent conservation action is now underway for the species to address these threats, led by BirdLife National Partner and Species Guardian, Aves Argentinas and local Patagonian NGO, Ambiente Sur, who are both working around the clock to prevent its extinction. During the first few months of 2012 (the austral summer in Patagonia) the two organisations led a substantial field team to the grebe’s breeding grounds to attempt a number of pioneering conservation initiatives.

The team visited 180 lakes in the remote plateaus of western Santa Cruz province, an area that covers nearly 20,000 square km. A total of 13 naturalists, ornithologists and biologists participated in the fieldwork, and new information was obtained about the reproductive biology of Hooded Grebe as well as the threats to its wellbeing.

The team’s first action was to assess the species’ abundance at known breeding colonies and investigate its presence at several new locations. Results from this survey confirmed its very precarious status, even though several new colonies were discovered. A total of 265 breeding pairs were located, of which just 64 were successful.

This year a pioneering new approach dubbed 'Colony Guardians' was trialled at El Cervecero Lagoon, one of the most important Hooded Grebe breeding locations on the Buenos Aires Plateau. Last year, the colony was wiped out when invasive American Mink slaughtered more than 30 breeding adult Hooded Grebes at this one site, leading to 40-plus eggs being abandoned. This year, a team of three scientists acting as Colony Guardians monitored the birds throughout the breeding season, with one of the team always present during the important stages of incubation, hatching and initial parental care.

This approach made a big difference, helping to protect the breeding birds from avian predators including their primary threat, Kelp Gull, which has been increasing throughout the province since assessment began in the 1980s. This year a breeding colony of the gulls was located at a site in the middle of the Buenos Aires Plateau for the first time, rather than at their historical breeding areas along rivers and the marine coast of Santa Cruz province.

In addition to combating aerial predation, the team also set a number of traps for mink. While evidence of mink was again clearly present this year, none were caught in traps, and apparently a human presence was sufficient to deter the mink from a repeat attack. As a result of the predator control actions, breeding success at the colony has greatly improved over the norm and some 60 per cent of nests were successful, with most of the young reaching the juvenile stage. This is a higher reproductive success than has been historically recorded for the species anywhere else.

Colony Guardians were also able to catch and apply individually marked wing tags to several adult and juvenile Hooded Grebes. The plan was to monitor these birds at the lakes as well as try to record them on their wintering grounds after they had migrated to the unfrozen fjords of the Santa Cruz south-eastern seaboard.

The wing-tagging activity is not without risk to the conservation team. To catch the grebes, a small inflatable dinghy is used to approach the birds in deeper water where they make their floating nests. The tagging operation is conducted in half-light and the naturally windy conditions at the lake make handling a small craft difficult. Falling in the icy water is clearly not to be recommended. Using a strong torch to distract and transfix the birds, they were caught in a long-handled fishing net and processed as quickly as possible to avoid any unnecessary stress.

The wing-tagging activity proved an instant success, with researchers able to monitor the progress and behaviours of individual birds with considerable accuracy, contributing to a far greater understanding of their ecology. One of the tagged juveniles, along with another juvenile and three adults, was found to still be present on the partially frozen El Cervecero Lagoon as recently as 8 May.

Remarkably, in the last few days, a wing-tagged juvenile Hooded Grebe has been seen at Rio Gallegos on the coast in the far south-eastern part of Santa Cruz province. This is not only the first time the origin of a wintering Hooded Grebe has been confirmed, it is also the first time a juvenile has ever been recorded on wintering grounds.

Throughout the summer the Hooded Grebe Conservation Team has also been working closely with landowners, local food producers and their staff, and local authorities, informing them of the uniqueness of the Hooded Grebe and its plight, and of the simple measures that can be undertaken to help secure its future. This has been a gradual process of building trust that will provide a strong foundation for future action, including support for the protected area, and on-the-ground action such as predator control and habitat restoration on private properties. A number of landowners are already actively collaborating with the team.

A proposal to the Argentinean Government’s National Parks Authority for the creation of a protected area within the Buenos Aires Plateau, which holds several colonies of Hooded Grebe, has resulted in feedback from the National Parks Authority to suggest that approval of a law creating a protected area may now only be a few months away. This would afford Hooded Grebe the highest level of legal protection available for its habitat.

The main area where introduced Rainbow Trout are a problem is south of the Buenos Aires Plateau in the Strobel Plateau. The effect of the introduced trout there has been so great it has reduced Hooded Grebe breeding by more than 98 per cent in the last 25 years. In addition to reducing food sources, the presence of trout leads to a change in the turbidity of the water which prevents the growth of vinagrilla, the filamentous plant that provides indispensable nesting material for all the water birds that breed in the lagoons. During the summer, substantial information was gathered by the Hooded Grebe Conservation Team about the impact of introduced trout in the lagoons there, which will be published shortly. This information will be used to inform provincial technicians and officials about the need to legislate appropriately to restrict further introductions.

As part of their outreach work in the area this year, the Hooded Grebe conservation team has also been holding meetings with mayors and other local government representatives to explain the threat that the introduced trout pose to the Hooded Grebe. These meetings have received a good reaction with offers of future support made by several stakeholders.

Next actions planned for the project are to repeat the work conducted this year but focus on some specific additional activities. Firstly the conservation team would like to increase the numbers of breeding sites at which Colony Guardians operate. If funding were secured, the plan would be to repeat the successful pilot at El Cervecero Lagoon at three additional colonies in 2013. Restoration of the lakes in the Strobel Plateau is also a priority. Several measures to reduce numbers of introduced Rainbow Trout and combat land erosion (which leads to silting) at various private lakes there will be attempted.

A third measure that builds on the initial wing-tagging exercise is to establish a satellite-tracking scheme. In this way it is hoped birds tagged with transmitters can be constantly monitored by conservationists throughout migration, providing important information about the routes they take, clarifying the risks they encounter and establishing where they spend the winter.

The cost of this urgently required action will be a minimum of $20,000 for the tagging alone, so unless more funding can be secured, very few of the planned measures will be possible in future years. BirdLife is looking for BirdLife Species Champions for the Hooded Grebe. If you or your company would like to find out about this opportunity please email species.champions@birdlife.org.