Scientists use plastic models to deceive birds and lie for twenty years

In the photo below, a group of birds with white bodies, black spots on their heads, and bright red beaks are gathering together. This is a waterbird called the Red-billed Tit (Hydroprogne caspia).

Crystal Shore, USGS

This seems to be an ordinary sight. But if you look closely, you can see that there are several birds that are not quite right-their bodies are too smooth and their postures are the same, as if they were the products of copy and paste.

In fact, these weird guys are indeed replicas, they are fake bird models made of plastic. For 20 years, a group of American scientists have been using these fake birds to "deceive" the feelings of the red-billed giant gull. This is done to protect endangered wild fish and to make these birds better off.

         Salmon survival crisis

In the Americas, red-billed giant gulls migrate northward each year from Mexico and Central America and then breed. Many red-billed giant gulls choose to nest on Rice Island in the Columbia River Basin and find fish to eat in the nearby waters.

This wasn't a problem at all-the Columbia River Basin was once one of the world's most salmon-producing regions, and its abundance of fish was enough to entertain waterbirds from afar. However, in the last two centuries, due to human fishing and dam construction, the number of wild salmon species such as silverfish and red salmon has decreased significantly, by about 95%. In this way, there is a conflict between the survival of fish and birds: the red-billed giant gull is also a wildlife that should be protected, but it is also an important hatchery for salmon. If the birds are left to eat the remaining young fish, they will recover. Wild salmon populations are getting harder.

Coho salmon (Oncorhynchus kisutch)

          Ask the Red-billed Titan to "move a house"

How to balance the interests of red-billed giant gulls and endangered salmon? The U.S. Army Corps of Engineers and federal fisheries biologists have decided to ask the red-billed giant gull to "move a house."

In 1999, before the breeding season began, they made fences with black fabric and erected wooden stakes with streamers. These birds don't like nesting in embarrassing places, which can "drive" the red-billed giant gull out of Rice Island by the Columbia River.

But just driving the birds away is not enough. Losing the original nesting site, where should the red-billed giant gull go?

At this time, it is the turn of the plastic model.

Researchers have found a good place for birds: East Sand Island, closer to the Pacific Ocean, where red-billed giant gulls can feed on catfish and herring. Red-billed giant gulls like to fly to their habitats in groups and stay with their peers to build nests. Researchers seized this feature and released 400 plastic red-billed giant gulls on Dongsha Island, and played recordings of the red-billed giant gull group before each breeding season from 1999 to 2001 to create The atmosphere of "bird thriving" hopes to seduce them.

Real and fake birds live in harmony

This attempt was quite successful. In 2001, all the populations of the red-billed giant gulls that originally inhabited the island of Mi Island were successfully relocated, and the proportion of salmon in their recipes quickly decreased from 83% to 30%.

         Explore more habitats

Since then, researchers have continued to monitor the movements of red-billed giant gulls, and to find and build new nesting sites for them. When the new island is ready, the plastic fake birds will continue to help these "social-loving" birds move to their new home.

The most recent "moving" took place in 2015-2017, this time, people chose Don Edwards San Francisco Bay National Wildlife Refuge. The protected area staff monitors the water level throughout the year to ensure that there is no drying up, providing an ideal shelter for a variety of waterfowl and waders.

San Francisco Bay, nestlings next to plastic red-billed giant gulls

In 2014, the U.S. Army Corps of Engineers remodeled the original five islands in the reserve. The following year, nearly 400 plastic red-billed giant gulls and solar outdoor speakers were placed on the island, playing their calls as they mated and nested.

Soon, the red-billed giant gull passing by noticed these signals. In 2015, 224 red-billed giant gulls nested on two of these islands. Two years later, the number of red-billed giant gulls here has doubled. After the breeding season in 2017, researchers have withdrawn plastic models and speakers-their mission is complete. Even if no longer attracted by fake birds, the red-billed giant gulls will arrive as scheduled in the next year's breeding season.

Although the feet of these red-billed giant gulls indicate that most of them came from near the San Francisco Bay, only a small part came from near the Columbia River. However, the red-billed giant gulls living in the reserve will attract more companions to build a nest life, and will always attract some friends of the Columbia River, thereby reducing the survival pressure of wild salmon. In addition, it is also beneficial for the red-billed giant gull to have more habitat.

Life scene of red mouthed giant gull

The breeding season in 2019 is over, and workers in the reserve are waiting for the arrival of the red-billed giant gull in the spring of the new year. They hope that the birds will continue to return to the carefully arranged island and bring more partners.

One question for everyone: "How many birds are fake in the initial picture?"