Bay Area Bird Identification: Least Versus Western Sandpipers

Cover photo: © David Ledig / U.S. Fish and Wildlife Service, 2006, some rights reserved.

Least or western sandpiper? Check out our compilation of identification knowledge to help you decide between the two species!

Cover photo: © David Ledig / U.S. Fish and Wildlife Service, 2006, some rights reserved.

When studying shorebird identification, I often found myself scratching my head – especially when it came to identifying two common, diminutive Bay Area sandpipers: the least and western sandpiper.

Peering through my binoculars at large groups of tiny peeps, my mind would second-guess itself: Those look like dark legs, but then again it is awfully muddy… 

For those of you that may also be scratching your heads on the other side of your bins, I’ve created this post as a compilation of identification knowledge that helps me most when discerning between the two species.

I’ve separated the article into two birding scenarios: observing a group of birds that looks like the same species (of least or western sandpipers) or observing a mixed-species flock in which you have narrowed down the species to least or western sandpipers.

If you see a group of birds that looks like the same species of either western or least sandpiper:

Clue 1: Check out those legs.

The first field mark that I tend to go for in the least versus western species diagnosis is leg color. Western sandpipers have black legs, whereas least sandpipers have yellow legs.

Yet it wouldn’t be as fun if it were that easy. As nature will have it, these small shorebirds are often foraging up to their legs in water. Also, the muddy habitats that they dwell in make it easy for mud to cake on their legs – making least sandpiper’s mud-caked leg look deceivingly like a pair of western sandpiper legs.

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Least sandpipers; Photo © Roy W. Lowe / U.S. Fish and Wildlife Service, 2011, some rights reserved.

Clue 2: What kind of habitat is the bird in?

As mentioned by Joe Eaton in his clever Bay Nature article “Meet The Smallest Sandpipers of the San Francisco Bay“, a tip for discerning between least and western sandpipers is to look at the habitat that you see the bird in.

Western sandpipers will often be found near the edge of water. Least sandpipers are more likely to be in vegetated habitat on ground further away from the water’s edge.

That said, it is important to note that mixed-species flocks are not uncommon – so be sure to pay close attention to the birds’ field marks.

If you see a mixed-species flock and have narrowed the species down to least or western sandpipers:

Clue 3: If the two species are side-by-side, also compare their sizes.

The “least” sandpiper, true to its name, is smaller than the western sandpiper – making identification a bit easier if the two birds are side-by-side.

That said, things become trickier when the species is being looked at on its own. For this reason, I would suggest relying on some tips mentioned previously to make a stronger case in your identification.

Western sandpipers
Note the heavier, more blunt-tipped bills on these western sandpipers when compared to the leasts in the photo above. Photo © Peter Pearsall / U.S. Fish and Wildlife Service, 2015, some rights reserved.

Clue 4: If the two species are side-by-side, compare their bills.

Western sandpipers have longer, thicker bills with a more blunt tip than the bills of least sandpipers. If you have the chance to compare the birds side-by-side, take note of how the western sandpiper’s bill also appears more “droopy” than a least sandpiper’s.

(Bonus): If you are surveying for eBird or another citizen science program, when in doubt just record the bird as “sp”.

eBird’s citizen science data contributes to research worldwide. Thus, it’s important to report exactly what we see and discern. This means that if you are in doubt, it’s better to err on the side of caution and report a “sp.” bird rather than guess just to settle on a species in your report.

There’s no shame in admitting that you weren’t able to tell the exact species identity – you are just doing your job as a careful and responsible citizen scientist!

Which sandpipers are we looking at? Answer is at the bottom of the page! Photo © Roy W. Lowe / U.S. Fish and Wildlife Service, 2011, some rights reserved.

Have any tips of your own? Comment below to add your take on deciding between least and western sandpiper!

Resources to Learn More



Answer to the photo above: least sandpipers! 

Park Sentries: Canada Geese

Cover photo: © Don DeBold, 2017, some rights reserved.

Learn about the Canada goose, a common visitor to California’s parks and fields.

Cover photo: © Don DeBold, 2017, Flickr Photo Album, some rights reserved.

The Canada goose has the most widely-distributed range of any goose in North America.

They are found year-round in parts of the northern United States. Birds that breed closer to the Arctic will migrate south to the United States for the winter. In some parts of California, there are areas where geese are found year-round. For more information on their range, check out this map by the Cornell Lab of Ornithology.

Their migratory v-formations headed north in the spring and south in the fall are widely recognized as symbols of the changing seasons.

Canada geese tend to forage in moist fields and manicured lawns.

There, Canada geese graze on grasses and grains from cultivated plants. Manicured lawns are particularly attractive to Canada geese, as the short vegetation allows them an unobstructed view of the landscape to look out for potential predators.

Canada geese are also known to eat aquatic plants.

Canada geese build their nests near water.

Females select the location, and do most of the work to construct a cup-shaped nest. They lay 2 – 8 eggs, which hatch after around a month of incubation. The hatchlings are covered in yellow down. As precocial hatchlings, they are able to walk, swim, and dive as soon as they leave the nest. The young will stay with their parents for a year, traveling as a family group.

Breeding pairs are monogamous, and have low rates of “divorce” – or splitting up. They form pairs usually during their second year of life.

When birdwatching, it pays to look closely at flocks of Canada geese.

I’ve been delighted during some birding walks to find another species mixed in with flocks of Canada geese. While at Shoreline Regional Park, I was lucky enough to find some greater white-fronted geese foraging with the Canada goose flock I was watching. Greater white-fronted geese are a rarer species in the Bay Area, so it was a treat to be able to watch them.

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Greater white-fronted geese foraging alongside Canada geese at Shoreline Regional Park in Mountain View, Ca.

Cool facts about Canada Geese:

  • Contrary to popular belief, the term “Canadian Goose” is incorrect. The common name of this species is “Canada Goose”.
  • Canada goose populations in urban areas have been increasing since the 1950’s.

Resources to learn more:

Bay Area Science: An Interview with a Kelp Biologist

Meet Sara Gonzalez, a kelp biologist from the University of California, Santa Cruz.

A view of the Pacific shore from Santa Cruz, Ca. Note the giant kelp floating on the water’s surface in the distance.

Gulls cried in the distance as we walked along the shore at Natural Bridges State Beach. The air was crisp with a twinge of salt. We had passed numerous brown mounds of kelp when Sara excitedly pointed to a kelp mass strewn on the beach closer to the water’s edge. We found just what we were looking for: giant kelp, Sara’s primary study species.

Sara knelt down beside a piece and picked up one of the bladesthe kelp’s leaf-like structures.

“You can see the really deep corrugations here, and the blade’s serrated edge.” She pointed to the corrugations, or grooves, carved into the kelp’s blade. She gently traced her finger along the serrated edges as I watched intently, realizing I would have missed these delicate details had I not been with Sara.


Giant kelp is widely distributed around the world, found along the coast of North and South America, Africa, Australia, and beyond. Distinct geological regions are home to giant kelp populations that look vastly different – despite being the same species.

“Some of these forms are so distinct that they used to be classified as separate species,” Sara explained. “Now they are termed ‘ecomorphs’ of the same species.” Different kelp ecomorphs, or individuals of the same species with different physical characteristics, vary in the form of their blades and the structures they use to anchor themselves to the ocean floor.

Sara Gonzalez is a graduate student in the Department of Ecology and Evolutionary Biology at the University of California, Santa Cruz. Previously, she studied biology at Cornell University. Trading upstate New York’s bitter winters for warmer weather and sandy beaches, she came to Santa Cruz to study kelp with Dr. Pete Raimondi.

Sara’s work with kelp began during a Fulbright Scholarship project in Chile. There, she collaborated with other marine researchers at the Pontificia Universidad Católica de Chile to study the influence of nutrients from fish excrement on kelp growth. I imagined her on the incredible Chilean coast studying its marine life, acquainting herself with the landscapes praised in poems by the famous Pablo Neruda.

While collaborating with Chilean academics studying kelp, Sara realized how embedded kelp is in today’s society as a natural resource. Kelp is harvested for its alginates, a polysaccharide found within the cell walls of all brown algae. When alginate combines with water, it forms a thick gum-like texture, which can be used in products ranging from cosmetics, daily-use items such as toothpaste, and foods such as ice cream.

“It was an interest that grew over time – being around kelp, and talking to people about kelp all the time. I got really excited about it,” Sara said, smiling and looking out towards the water.

Sara examining kelp on the beach of Natural Bridges State Beach.

Kelp is a foundation species, meaning it plays an important role in its community. It also forms an entire ecosystem: the kelp forest.

“The high productivity of the kelp forest and varied physical structure from the base to the canopy provide the foundation to support a diverse array of life, including many commercially and recreationally harvested species such as kelp bass, several species of rockfish, and the kelp itself,” Sara explained.

Organisms, ranging from invertebrates to fish to mammals, rely on kelp forests as a place to live, forage, and reproduce. Kelp forests also protect shorelines from erosion by creating drag against waves coming to shore.

Sara’s time in Chile piqued her interest in the morphological differences between Californian and Chilean kelp. This interest grew into a well-formed project as a graduate student. At Santa Cruz, she is studying the environment’s role in determining the kelp ecomorphs and its effects on the production of alginate.

However, today, we were two just two naturalists combing the beach shore.

We approached another mass of kelp, flushing a swarm of small insects as we knelt down beside it. Sara, ignoring the insects, reached down her hands to pick up a kelp mass the size of a soccer ball.

A kelp holdfast, held by Sara.

“This is the holdfast,” she explained, turning over the ball, which appeared to be a mass of root-looking structures. “It’s composed of haptera, which are these root-looking things.” She pointed out the network of twisting haptera, growing tightly together in a pattern which resembled the creases of a brain.

On our coast, giant kelp forests grow up to 50 meters from the ocean floor, eventually reaching the water’s surface.

“As it grows, the kelp forms more and more of these haptera, until you end up with this big, netted mass of them.” Sara slowly turned over the holdfast for me to see, pointing out the layers the haptera formed. Despite its resemblance to a mass of plant roots, she explained, a kelp’s holdfast doesn’t act like a root system at all. Rather, it’s used by kelp to anchor itself to substrate. She carefully placed the holdfast back near the pile of kelp blades.

Over the course of our walk along the beach, we encountered 3 different species of kelp: the giant kelp with its densely grooved blades, the chain bladder kelp with its line of bubble-like protrusions, and the feather boa kelp, which looked, not surprisingly, like a long feather boa.

However, our giant kelp specimen was by far the most physically impressive. Scientifically, giant kelp is equally astounding: it is one of the fastest-growing plants in the world, accumulating 12 to 18 inches of growth per day. Their high growth rates make kelp forests one of the most biologically productive communities – comparable to tropical rain forests.

Moving forward, Sara plans to continue her kelp studies by conducting a series of experiments. By rearing kelp in the lab and simultaneously planting them in the ocean, Sara will be able to elucidate the importance of environmental versus genetic factors in kelp morphology and alginate production.

Sara’s work in Chile also shed some light on the importance of nitrogen in fish excrement for kelp growth, and its role in reducing blade decay. These preliminary results prompted Sara to focus on the effects of ammonium on kelp – being the nitrogen product from fish excretion, after the ocean’s pH conditions react with the ammonia from the waste. Less is known about ammonium’s effects on kelp when compared to its close chemical relative, nitrate.

“In parts of California, there are times of the year when nitrate levels are reduced, so it is important to understand the potential contribution of fish-derived nitrogen, especially as oceanic conditions in the future are likely to change,” Sara explained.

We continued down the shore, eventually reaching a rockface with shallow pools carved into it. Inside the pools, anemones dotted the edges like flowers, their tentacles spread out like delicate sea petals. Around the pools, masses of washed-up giant kelp spread out like carpets on the rocks.

I thought of the kelp’s holdfast: its dense network of haptera forming a stronghold to the ocean floor as the kelp grows towards the water’s surface. Then, I thought of Sara. Her ideas seemed to grow in an analogous way, forming a dense network of enthusiasm and curiosity to anchor her as she reaches towards the answers.

We returned to the beach and meandered back towards my parked car, absorbed in our conversation as gulls flew overhead.

Footprints in the sand along Natural Bridges State Beach.

If you are a scientist living in or around the Bay Area and are interested in an interview, feel free to contact bayareanaturalist (at)

Forest Clovers: Redwood Sorrel

When hiking in redwood forests, it’s likely that you’ve encountered redwood sorrel in the forest understory. A true shade-lover, redwood sorrel will fold its leaves when exposed to direct sunlight.

Places to See Redwood Sorrel

Cowell Circle

Henry Cowell Redwoods State Park

Redwood sorrel folds its leaves when exposed to direct sunlight.

When the leaves are in direct sunlight, they shrivel up and fold downwards within minutes. Sensitive cells in the plant detect the wavelength of light hitting it, causing the leaves to fold downwards when exposed to harsh light. This process is called nyctinasty.

Redwood sorrel’s folding is attributed to its sensitivity to bright sunlight. Because it is adapted to growing in low light conditions, intense light can damage the plant. Thus, folding its leaves is thought to protect it from harm.

To watch a time-lapse of this movement, check out this YouTube video. Please note that the plant shown is Oxalis triangularis, a different plant species in the same family as redwood sorrel.

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Redwood sorrel in bloom at Limekiln State Park in Big Sur, Ca.

Redwood sorrel is found on the West Coast of North America, from California to Canada.

It prefers understory habitats, often growing in coast redwood or Douglas fir forests beneath the shade of trees. It is one of the most common plants in the coast redwood understory.

Redwood sorrel leaves resemble clovers.

The leaves are 0.4 – 1.8 inches long. Redwood sorrel also has tiny (0.5 – 0.8 inch) flowers, which range from white to pink in color. Flowers can be seen in bloom from February to September.

Redwood sorrel is a good replacement for English ivy in a native plant garden.

Looking to make the conversion to native plants in your garden? Alternatively, are you looking for more native plants to introduce to your existing native garden? Consider the redwood sorrel. This plant grows well in shady conditions, forming a dense carpet beneath trees.

For more information on the planting and care of redwood sorrel in your garden, check out this article by S.F. Gate.

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Redwood sorrel at Henry Cowell Redwoods State Park in Santa Cruz, Ca.

Cool facts about redwood sorrel:

  • Redwood sorrel is truly adapted to shady environments, as it is able to photosynthesize in levels of light that are 1/200th of full sunlight.
  • The family name of redwood sorrels, Oxalis, is derived from the Greek word “oxys”, meaning sour. This is because the leaves of plants in this family have a sour taste.
  • Beware of eating too much of any plant in this family, as they contain oxalic acid. Oxalic acid can be toxic when consumed in large quantities.

Resources to learn more:

Explore Santa Cruz Redwoods at Henry Cowell Redwoods State Park

Santa Cruz, Ca – Home to four different ecosystems – redwood, riparian, sandhill chaparral, and grassland – Henry Cowell Redwoods State Park is an exciting experience rich in biological diversity.

Species to Look Out For

About the Park

Santa Cruz, Ca – State Park

Science Spotlight: One Park, Four Ecosystems

We began our hike at Henry Cowell Redwoods State Park in a riparian habitat – a habitat characterized by being adjacent to a river or stream. As we passed by the San Lorenzo River, I couldn’t help but admire the clear water running over smooth, flat stones. Close to the water’s edge, a black phoebe perched on a low-hanging branch, ever-ready to snap up unsuspecting insect prey.

As we made our way uphill, more and more redwoods began to tower above us. Their shade created cool microclimates – refuge from the September sun’s heat. The coast redwood bark formed gnarled knots at the bases of the trees. The bark smoothed out as you craned your neck to follow the tree’s trunk upwards. The sounds of the river earlier on our walk were replaced with the sharp calls of Steller’s jays.

Over the course of our hike, we had the chance to witness just two of the four ecosystems present at Henry Cowell Redwoods State Park: riparian and redwood habitat. The state park’s unique geologic history has shaped it to be the home to redwood forest, riparian areas, sandhill chaparral, and human-created grassland ecosystems.

The park is a mixture of different types of rock formations: to the north, the park is dominated by softer sandstone and mudstone. To the south, the park is comprised of harder rock formations such as granite and schist. The variable geology in the different regions of the park laid the foundation for the diversity of ecosystems that we are able to observe today. The diversity of ecosystems also begets diversity of species – making a visit to Henry Cowell Redwoods State Park a rich and exciting experience.

Park History

The park’s area is deeply-rooted in California’s industrial history. The surrounding area was logged for lumber, and the park itself was once home to a busy lime industry. The area is rich in limestone, which when heated in a kiln, becomes lime – an important material for building. Much of the surrounding forest was cut and burned as fuel for the operating kilns. The lime kilns operated from 1865 to 1919.

The park was also the site of an important moment in Bay Area conservation history. Andrew P. Hill, a local photographer, visited the redwood grove in the area to photograph the towering coast redwood trees. After a confrontation with the owner of the grove’s operating resort, Hill formed the Sempervirens Club, whose mission is to protect redwoods so that they can be enjoyed by the public (see the related park history for Big Basin State Park).

In 1930, Santa Cruz County took control of the resort, resulting in the land’s dedication as a county park. In 1954, Samuel Cowell joined his family’s land to the county park, resulting in the naming of a new state park after his father, Henry.

Visit the Park

Please note that there is no entrance fee to enter the park. Dogs are allowed at select locations in the park. For more information on where dogs are and are not allowed, visit the California State Park site’s General Information for the park.

Here are some helpful resources to help plan your visit:


Lantern Flowers: Crimson (Western) Columbine

Learn about this outstanding Californian wildflower – from its evolutionary history to the best time to see it bloom.

Crimson columbine is native to California.

Its full native range extends up north to Alaska’s coast, and east into Idaho, Montana, and Wyoming. It is also found in areas of the Southwest. They are absent in California’s Central Valley.

Columbines are hypothesized to have arrived to North America 10,000 to 40,000 years ago.

Scientists hypothesize that the columbine ancestor made its way from Central Asia to Alaska thousands of years ago by the the Bering land bridge that connected Asia to North America. Evidence of the columbine’s travels have been supported by DNA analyses of columbine species from around the world.

After its arrival in Alaska, the columbine ancestor begin to radiate out to other parts of North America. The evolution of North American species is hypothesized to be driven by pollinator specialization. For example, multiple species of red columbines have adapted red flowers (distinct from blue and yellow-flowered columbines found in other parts of the U.S.) and higher sugar contents in their nectar – an adaptation thought to meet the demands of their hummingbird pollinators.

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Crimson columbine at Purisima Creek Redwoods Preserve.

The best time to see crimson columbine bloom is March – May.

The plant can be found in forest and meadow habitats where the soil is moist.

The outer, red parts of the flower are actually sepals. The “true” petals are the yellow parts on the inside of the flower. Overall, the entire flower is about 2 inches long.

Crimson columbine attracts pollinators, including hummingbirds.

These flowers are also relatively deer-proof, making them a great option to include in a California native plant garden. For more tips on how to cultivate crimson columbines in your garden, check out these tips from the Las Pilitas Nursery.

Cool facts about crimson columbine:

  • Its genus name, Aquilegia, is derived from the latin word aquila, meaning “eagle”. This name is thought to refer to its upright red sepals, which look like an eagle’s talons.
  • The flower’s common name, columbine, is derived from the latin word columba, meaning dove-like.
  • Crimson columbine is a perennial plant.

Resources to learn more: