The initial successful redistribution of Caspian terns

The initiative to build a new nesting area for the largest terns in the world and at the same time protecting the salmon and baby sharks on the Columbia River has finally achieved initial success.

A study of the new nesting site on southern Crum Lake in Oregon, built in February by the US Army Corps, attracted more than 135 Caspian terns as well as thousands of seagull pairs. 2 pairs of cormorant birds came to nest.

The redistribution of terns is important because according to research by Oregon State University scientists, terns and cormorants consume more than 10 million salmon and shellfish every year. Columbia emigrated to the Pacific Ocean. They themselves helped lure the Caspian terns to Crumps Lake, located northeast of Lakeview, using bait birds and sound terns recorded at the mouth of Columbia River.

Dan Roby - Oregon State University professor of the Fish and Wildlife Service and the principal investigator of the study - said: 'It's amazing that over 520 Caspian terns have arrived at the island just recently. built 5 months ago. Some have decided to nest here. Crump Lake was once their nesting place so they seemed to keep a little memory of this place. This is the main key to success. '

Terns.(Photo: flickr.com)

Collaborative efforts between the US Army Corps, Oregon State University, Real Time Research, Inc., together with the Fish and Wildlife Service in collaboration with Oregon Geological Research Agency have provided funding. $ 2.1 million for Oregon State University from Bonneville Competency Authority and Corps.

According to Geoff Dorsey, a wildlife animal biologist in collaboration with the Portland County Corps, the Corps's Raptors program aims to reduce the number of baby salmon eaten by terns at the doorway. The river, from which 'substantially enhances survival for the listed fish species' under the Threatened Species Protection Act.

According to the researchers, the project initially aims to redistribute the most crowded Caspian terns in the world. Last year, Oregon State University researchers identified about 9,900 pairs of terns nesting on East Sand Island near the Columbia estuary, accounting for about 70% of all Caspian terns living in the Thai coast. Binh Duong from Alaska to Baja California.

In the late 1990s, the Corps moved the terns to East Sand Island from Rice Island - a position 16 miles upstream on the Columbia River - after the Oregon State University team directed the discovery. Terns at that place have about 12 million salmon a year, estimated at 10% of the amount of salmon in the entire Columbia River basin. East Sand Island is only 5 miles from the ocean, the waters here are home to a wider variety of fish than the upstream freshwater near Rice Island, including herring or drumfish.

Roby said: 'Terns are fish eaters, they consume a large number of small fish. When we looked at what terns on Rice Island ate, we found that three-quarters of their diets were salmon and small fish. This is not good at all. '

According to Oregon State University researchers, Rice Island is perhaps the "worst place" for the world's most crowded Caspian terns with the prospect of restoring 13 threatened salmon and shellfish at Columbia river basin.

Roby pointed out that the initial move had more successful signals than expected. The East Sand Terns consume less than half the amount of salmon and shellfish compared to the swarms of Rice Island, estimated at 4 to 6 million fish a year. 'But that's still too much,' he added. Project investigators continue to take the second step of the plan to redistribute terns to many new nesting sites away from the Columbia River.

Roby said: 'The world's largest Caspian swarm remains at the mouth of the Columbia River. Although East Sand Island is a major improvement over Rice Island, we always consider it the first step to implementing the solution. There are still many terns that need to be relocated because they greatly affect the survival of threatened salmon species in the entire Columbia River basin. '

'Some people suggest shooting down terns to protect the fish, but that solution is not practical at all. Caspian terns are not large numbers. They just happen to focus on nesting in one place and turn that place into an unlucky place. '

One reason for the ternary empire of the terns at the mouth of the Columbia River is because their former nesting sites in the western United States were destroyed by human activities . The exhaustion of wetland habitats in some places, the flooding in some others has destroyed their favorite nesting environment - the bare sandy islands.

Cormorant.(Photo: flickr.com)

Currently, implementing the plan of the US Fish and Wildlife Industry, Corps and NOAA Fisheries, the research team led by Oregon State University has embarked on restoring nesting sites. replacement for Caspian terns. In addition to the location on Lake Crump, the Corps also created an artificial island at the Fern Ridge reservoir in the Willamette Valley. They plan to build 3 more half-acres islands in the wildlife area on Summer Lake in southern Oregon this summer and next summer. The Summer Lake project involves the construction of a semi-floating island made of recycled plastic with coarse gravel and sand surfaces.

Crump Lake and Summer Lake are two places where terns once nest, but Fern Ridge does not. So far, the terns to Fern Ridge nest at a slow pace.

Roby said: 'We know that Fern Ridge will be a long-term project that can take several years to succeed. The first step is to provide a living environment. We then added elements of social appeal such as bird prey and sound system . We now need to limit people and predators to wait for the birds to come to the nest '.

The artificial islands are all made up of dredged materials on the Columbia River - the perfect nesting environment for birds - which has been carried out since 1930 but only in 1984 did the new Caspian terns build their nest. these places.

The Caspian tern management project also requires restoration of three other nesting sites in the San Francisco Bay Area, where there is also a research group at Oregon State University.

The construction of an alternative habitat on nearby Lake Crump and Lake Summer will help the Corps reduce the area of ​​nesting terns on the East Sand Island of Columbia, about one acre in 2009. According to reports of environmental impact. In the case of incident, it is necessary to reduce a sample at East Sand when constructing two alternative nesting areas somewhere. Dorsey said that the project had to keep 1.5 to 2 samples for the Caspian tern nesting on East Sand Island, enough to maintain the herd of about 1/3 to half the size of the current herd.

According to Dorsey, East Sand Island could basically just need to maintain the nesting environment for about one and a half acres according to the final project if enough alternative sites are built elsewhere.

Roby said redistributing terns is inevitable. When researchers set up a new herd on East Sand Island, they were unsure whether the terns could grow. They are also not sure whether this conversion step will reduce the amount of salmon eaten. Terns also need to be protected from predators such as seagulls. An estimated 200 seagulls - a much larger number - have been shot in the past two years at the nesting site of East Sand Island.

Seagull.(Photo: Alan Mackenzle / flickr.com)

Roby said: 'Officials from the National Audubon Association's Seabird Restoration Program told us that perhaps we are taking some measures to control seagulls or that they will prevent terns from development '.

With over 1,000 pairs of seagulls on the new island of Crump Lake, the terns are difficult to protect their eggs from much warmer voracious people. The spawning season in the mid-June period, researchers hope to see newly hatched young birds in 2 to 3 weeks.

There is also an inevitable question about the diet of terns on Crump Lake. Most of the birds ate the goby or small goby in abundance - the fish illegally imported into Diamond Lake, causing local officials to poison the Diamond Lake to eliminate them. The small goby is an endemic species at Crump Lake that provides a stable food source for fish-eating birds, including terns.

Oregon State University researchers and the Corps built a barrier on the island to study the Caspian terns, cormorants and gulls while avoiding affecting them. They observed the swarms gathered from previous studies. Since then, some have come from East Sand Island and Rice Island in the Columbia estuary, while others reside in Potholes reservoir near Lake Moses - Washington, and Crescent Island near Pasco - Washington.

Dorsey said: 'We are very happy to see the birds coming here from many locations. They help prove that they can attract terns to alternative locations away from the Columbia River '.

Roby repeated that the project's goal is not to reduce the number of Caspian terns in the region, estimated at 13,000 to 14,000 pairs. The project simply aims to redistribute the number of individuals to reduce the impact of terns on the survival of the salmon in the Columbia River basin. For example, the study revealed a group of about 500 pairs of Caspian terns that consumed one-third of the Snake trout while migrating through the territory of the birds on a drought year.

'The goal is to limit disagreements between protected migratory birds such as Caspian terns and threatened fish populations such as the Columbia river trout and cobia to create or restore new habitats for the flock. birds in areas where the fish are protected do not account for the majority of the birds' diet.

'The new island on Lake Crump is a restoration of a natural island that was destroyed in the 1950s by archaeologists. This is also a big step in the right direction. '