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The Watershed Project

migration

What’s in Your Watershed? | The Watchful Greater Yellowlegs


By Ana Weidenfeld

Yap! Yelp! Yellow! Now is the time to spot the Greater Yellowlegs (Tringa melanoleuca) in the Bay Area. Though this is one of the most widespread shorebirds, the Greater Yellowlegs only breeds in central Canada and southern Alaska. In late June, this graceful bird moves south to spend the winter months in fresh and saltwater wetlands in the United States and Central and South America. In the springtime, they begin to return north. The Greater Yellowlegs are more solitary than most other shorebirds but they can form small flocks during migration.

Aside from the obvious long yellow legs, you can tell that you’re looking at the Greater Yellowlegs by its upright stance. It is a medium-sized bird with a long neck and a bill that is slightly upturned and rounded. These features set it apart from the Lesser Yellowlegs (Tringa flavipes), which has a sharp, pointed and dark colored beak and also emits a different cry. The Greater Yellowlegs has a white rump and tail, with darker wing feathers. Its wingspan, for both sexes, measures around 60 centimeters.


Another telling sign that the Greater Yellowlegs is nearby is its sharp and intense call of three or four notes. The bird calls out a piercing squawk at any sign of trouble, explaining its nicknames of tattler and yelper.
The Greater Yellowlegs enjoys feeding on a variety of invertebrates and small fish, which are ample in Bay Area wetlands this time of year. This bird is also known to eat small frogs, crustaceans and occasionally berries and seeds. These yelpers feed by wading through shallow waters, bobbing their heads up and down and sweeping their bills side to side in order to feel and catch prey.


The Greater Yellowlegs, like most shorebirds, builds its nest in a concealed area on the ground by making a small depression in the soil and filling it with leaves, mosses and twigs. Greater Yellowlegs birds are thought to pair for life and raise one brood a season, with both parents helping to incubate the four eggs for about three weeks. New hatchlings are remarkable in their ability to leave the nest within a few hours!

An apparent mud-lover, the Greater Yellowlegs chooses to breed in boggy land that is brimming with mosquitoes, making it one of the most ubiquitous shorebirds without much known about its breeding biology. As frustrating as this is for scientists, the low density and hidden nests of this bird also work to shield the population from possible threats. Furthermore, their ability to change migration times and wintering habitat will no doubt help the population in the face of increased wetland habitat destruction in the future.

Keep an eye and ear pealed for this yellow-legged dandy!

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What’s in Your Watershed? | The Vibrant Bay Checkerspot Butterfly

By Stefanie Demong

It’s autumn in the Bay Area and this native butterfly is wearing all the right colors. Bay Checkerspots, of brush-footed butterfly descent, boast two-inch black wingspans dotted bright red, yellow and white.

This butterfly’s spots suggest its other big claim to fame. The insect’s checkerboard-like habitats inspired Paul Ehrlich’s theory of metapopulation. It was the checkerspots’ scattering across the Bay that led the infamous Population Bomb doomsayer to identify groups of spatially distant populations of the same species that may still interact.

Ehrlich began researching the commonplace checkerspots in the 1960s. At this time, there were many small, isolated patches of checkerspots in different pockets of the Bay–from Twin Peaks in San Francisco to the San Bruno Mountains in the west, to Mount Diablo in eastern Contra Costa County, and down into Santa Clara County, as far south as Hollister. Ehrlich found that these populations, sometimes connected by migration, endured periodic extinction and resurgence through recolonization–meaning, one group would move into the empty space left by another group’s demise.

Unfortunately, the Bay checkerspot population suffered a major decline starting in the 1980s. By 1987, they were officially designated an endangered species. Ehrlich’s specimens at the Jasper Ridge Biological Preserve went completely extinct by 1998.

Ecologists speculate that because checkerspots rely on native dwarf plantains (plantago erecta) as larvae hosts, any number of local stressors may be at fault. Climate change may alter the plantain growing season; ongoing construction of homes and highways, traffic exhaust or the use of pesticides can disrupt both butterfly and plantain growth; the arrival of invasive grasses has changed the soil composition.

The US Fish and Wildlife Service have led extensive checkerspot conservation efforts while Stanford University has backed studies on the species’ reintroduction to the Bay. Many believe that protected zones should be arranged in “stepping stone”-like pattern and proximity to encourage the intermingling behavior described by Paul Ehrlich. The hope is that someday, with careful practices and policies, checkerspots may once again grace the Bay Area.

Illustration and Photo Credits (from top): David Fierstein, The San Francisco Chronicle/Michael Maloney, KQED QUEST Flickr Set.

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What’s in Your Watershed? | The California Coast Range Newt

By Madeleine Foote

When the winter rains come, we humans tend to remain inside, but for the California Coast Range Newt, the rains are a signal to leave their summer homes and move to the water. If you are lucky enough to see one this season, be content with just looking. One of five salamander species in California, this newt’s skin produces a highly toxic poison called tetrodotoxin that can cause respiratory and cardiac failure.

Physical Appearance
The average California Coast Range Newt is 5-8 inches long, with a stocky, muscular body and legs that bend downward at the elbows. It has four toes on each leg and big eyes that extend past the outline of its head. The newt’s brown color lets it blend in with the leaves and brush it hides in. If you see his yellowish-orange underbody, however, watch out! When threatened, the newt will stick its tail straight out and bend backwards, exposing the bright underbelly as a warning to predators.

Diet
This “gold belly” newt likes to dine on small invertebrates such as worms, snails, slugs, insects, insect eggs, and amphibian larvae, but has been known to become cannibalistic when other foods are unavailable.

Habitat
As the name would suggest, the California Coast Range Newt can be found in the coastal regions from Mendocino to San Diego counties, living in oak forests, chaparral, woodlands, and rolling grasslands. In the summer, the newt spends its time in moist habitats: under woody or leafy debris, in rock crevices, and in animal burrows. During the rainy season, the newt migrates to ponds, reservoirs, lakes, and slow-moving streams.

Mating and Life Span
When the rainy season has begun in earnest, the newt focuses on romance. Mating season lasts 6-12 weeks, when large numbers of the newt move together, often traveling across roadways and highways. Right here in Contra Costa county’s Tilden Regional Park, South Park Drive is closed between November and March to allow for newts to cross the road to their breeding grounds in Wildcat Creek. Also, dedicated volunteers in El Sobrante gather each year to escort newts across a drop structure to reach their breeding grounds along Castro Creek.

Baby newts look like legged tadpoles, but by early fall, the newborn newts will develop a more warty skin, the orange coloring typical of adults, and will transition fully to living on land. California Coast Range Newts are thought to live 20 years or more, with few natural predators except the common garter snake, which has developed a genetic mutation against the newt’s poison.

Conservation Status
The Coastal Newt is listed as a species of special concern in California, but has no federal conservation status. Its biggest threats are habitat loss and degradation, and predation of eggs and larvae from invasive species. It is illegal in California to have or sell these newts as pets, and they are best left to roam in the leaves and creeks of our watersheds.

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What’s in Your Watershed? | The Lovely Long-billed Curlew

By Dan Grannan

The long-billed curlew is an epic bird. Not only is it the largest shorebird in North America, it also displays one the greatest aerial shows of any avian flier. During breeding season, the curlew flies in fast loops as part of a courtship dance. This ostentatious display attracts both feathered mates and human bird-watchers alike. Named for its long, slender bill and “cur-loo” call, curlews are also called “candlestick birds” and are the namesake for San Francisco’s Candlestick Point.

Physical Appearance
Adult curlews have an elongated bill that curves downwards, a long neck and a small head, while the chicks have a much smaller and less curved bill. The females have a much longer bill than the males. Curlews’ underbelly and neck are cinnamon-colored and their crown and back are speckled with various shades of brown.

Range and Habitat
The long-billed curlews breeding range is massive. It spans from southern Canada to northern California, and also includes Utah, northern New Mexico and Texas. The curlew loves the sun and winters in California, Texas, Louisiana, and South Carolina as well as Florida, Mexico, and Central America. This range used to be much larger with massive numbers being found along the Great Plains and eastern prairies. Increased agriculture and livestock grazing has shrunk the range of the curlew.

Diet
In the summertime, curlews sample grasshoppers, beetles and crickets from the grasslands. Throw in a small amphibian from time to time and you have the ideal summer diet. During the winter months when the bird is sunning on the beach, small crustaceans, mollusks, berries and seeds are its delicacies of choice.

Child Rearing
Mama curlew lays four eggs in a grass-lined nest and incubates them for about one month. Papa curlew assists by taking turns warming and guarding the little eggs. Mama and Papa curlew use their multi-colored feather coats to camouflage and protect the nest from predators. Skilled actors, the adult birds are known to feign injury to lure potential egg-snatchers away from the nest. They also can take a more direct approach if needed, using loud vocalization and dive bombing to deter predators. Once hatched, the chicks are almost fully independent. The adults teach them to hunt grasshoppers and watch over them for up to 45 days, and then they are on their own. The average curlew life span is eight to ten years.

Conservation Status
Under the U.S. Shorebird Conservation Plan curlews are currently slated as “critically imperiled.” Habitat destruction is a major concern for the curlew. As marshlands are shrinking and prairie lands are developed or converted to farmland, the curlew is losing its potential habitat breeding grounds. With a current population size of only 123,500, monitoring and protection efforts are critical to ensure this population does not suffer the same fate of many other extinct species. You can help protect this lovely bird next month by joining The Watershed Project on International Coastal Cleanup Day to ensure that curlew habitat is free of marine debris.

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What’s in Your Watershed? | The Mighty Red Knot

By Christopher Lim

What weighs less than half a pound and travels over 9,000 miles each year? The Mighty Red Knot, Calidris canutus, is a truly remarkable bird. It makes one of the longest yearly migrations of any bird, traveling over 15,000 km from its Arctic breeding grounds to Tierra del Fuego at the tip of South America, flashing its colorful body and wings the entire way.

Physical Appearance
One of the most colorful birds in North America, Red Knots change color depending on their motives. During breeding season, it has an attractive cinnamon colored face, chest and undersides and dark brown wings. In winter, the Red Knot dons a more modest color scheme, with a gray head, chest and upper parts and a white belly. It has a pointed black bill and long, greenish legs. Males and females look similar. The weight varies with subspecies, but is between 100 and 200 grams. An adult Red Knot is 23-26 cm long with a wingspan of 47-53 cm.

Range and Habitat
The Red Knot is a world traveler. It breeds in drier tundra areas in the Arctic regions of Canada. The Red Knot then makes an unbelievable trek down to South America via both the Pacific and Atlantic coasts, often making stopovers in the mud flats of the San Francisco Bay. The Red Knot is also found in Europe and Asia. Outside of breeding season, it is found primarily in intertidal, marine habitats, especially near coastal inlets, estuaries, and bays.

Diet
Red Knots like seafood. They eat mainly invertebrates, especially bivalves, small snails, and crustaceans. On the wintering grounds red knots also eat a variety of hard-shelled terrestrial invertebrates that are ingested whole and crushed by a muscular stomach.

Mating
Red Knots are flashy creatures. During courtship, the male Red Knot flies up into the air, starts singing, glides around a bit and then lands with his wings pointed up. The female Red Knot lays three to four eggs in a depression in the ground. Both parents incubate the eggs. In fact, the male may do most of the incubation. The chicks hatch in approximately three weeks and they fledge in another three weeks.

Conservation status
As fellow watershed dwellers, it is important for us to protect this fascinating bird’s habitat. The fact that Red Knots come together at traditional staging areas during migration makes large groups vulnerable to pollution and the loss of food sources. The numbers of Red Knots appear to be declining; the populations wintering in South America dropped over 50% from the mid-1980s to 2003.

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