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SACRAMENTO FWO: Endangered Bird Gets a Home Away from Home
California-Nevada Offices , August 2, 2012
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U.S. Fish and Wildlife Service and partners are working to create a safe place for the endangered California clapper rail to raise the next generation.
U.S. Fish and Wildlife Service and partners are working to create a safe place for the endangered California clapper rail to raise the next generation. - Photo Credit: USGS
California clapper rail is a subspecies that can only be found in the San Francisco Bay.
California clapper rail is a subspecies that can only be found in the San Francisco Bay. - Photo Credit: Andy Raabe/USFWS
Floating islands being used by the endangered California clapper rail.
Floating islands being used by the endangered California clapper rail. - Photo Credit: Andy Raabe/USFWS

By Ashley Cotter, Summer Intern, Sacramento FWO

In some situations, preserving the habitat of a species can be detrimental to the surrounding species. This is the case with the California clapper rail in the San Francisco Bay.

Clapper rails are chicken-sized birds which rarely fly, and the California clapper rail is a subspecies that can only be found in the San Francisco Bay. With a compact body, strong legs, and a short tail, the rail is a grayish brown colored shorebird with a pale chestnut colored breast, and white patch under the tail. It uses its long orange-brown bill to search for arthropods, creatures like snails, mollusks, etc., that they feed on in the mudflats of tidal marshes.

They are distinctive, but you probably have never seen one on your walks along the Bay. Although large for a shorebird, rails are shy and tend to be heard and not seen. Their call is a short series of clacking or grunting notes. You can listen to the rail’s call on the Cornell Lab of Ornithology website, so next time you are near the Bay you know what to listen for.

The rail’s endangered status has stemmed from issues with predators and loss of habitat, as more marsh land is developed into housing. A new threat to these birds is climate change and the effects of water level changes. As the water rises, it threatens what little habitat remains for these rare birds. As if that wasn’t bad enough, the rail has been struck hard in the last few years as conservation actions to help preserve the marsh plant diversity have had an unexpected and negative effect on the rails. With the removal of invasive Spartina, a non-native plant, the birds are losing yet another place to hide from predators and make their nests.

This non-native plant has invaded many marshes in the San Francisco Bay and is a threat to both the marshes themselves, as well as the native plants that it has overrun. The threat of the invasive Spartina has led to the Invasive Spartina Project and other organizations working to control the plant’s spread.

The answer seems simple, get rid of or control, the invasive Spartina and save the ecosystem of the marsh. Unfortunately, it's not that simple.

The endangered rails have been using this non-native plant to hide during high tides. Without this plant the birds become exposed, and their species could slip even closer to extinction. Remember, this bird rarely flies and when it does it is only for a short distance, so the bird’s best defense is finding a place to hide. Predators include stray cats from nearby neighborhoods, hawks and other raptors that perch on power lines, rats, and foxes. With only eight percent of San Francisco’s original marshland remaining, the rails have very limited space to escape from the vast array of predators.

So how is the invasive plant controlled without threatening the entire population of the endangered rail? As they lose places to nest in the invasive plants, what will take its place?

The U.S. Geological Survey, the California Coastal Conservancy, and the U.S. Fish and Wildlife Service, are involved in the Invasive Spartina Project which started in 2010.  Not only are they working to eradicate the plant, they are working to create a safe place for the rails to raise the next generation of chicks. Floating islands are now serving as refugia habitat for the birds. The islands are only temporary, but are being used to study the effects that the control of the invasive Spartina has on these birds. The thought is that the rail can eventually use native plants to shield them from becoming prey; however, these native plants need time to reclaim the marsh, thus the need for the temporary islands.

The floating islands are small, man-made islands made of recycled plastic bottles and/or Styrofoam that float on the water with changing tide levels. They support woven palm screens, similar to what duck hunters use in duck blinds. The islands are numbered according to their location in the marsh and monitored to track which species benefit from the islands.

So far monitoring has shown that rails have been occupying all islands, with visit numbers ranging from 190 to nearly 12,000 during October-December. The monitoring has also shown that the islands get the most use at high tides when the marsh is mostly flooded.

The marsh habitat is just another example of how fragile ecosystems can truly be. The invasive Spartina needs to be controlled in order to allow native Spartina’s regrowth, however, until the native plants come in the animals of the marsh are left with nowhere to escape from predators and raise their young.

No tall plants in a marsh are the equivalent of no walls in our cities. Remove one species, whether plant, animal or insect, and the building blocks of an ecosystem can tumble down.

The project is still underway and new data is being acquired and monitoring will continue on the islands for a few more years. It is hoped that once the native Spartina returns and the walls of the ecosystem are rebuilt, the California clapper rail will have a stable home once more, and continue on the road to recovery which is the ultimate goal of the Endangered Species Act. For more information on this and other endangered species, visit www.fws.gov/sacramento.

 

 


Contact Info: Sarah Swenty, 916-414-6571, sarah_swenty@fws.gov



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