A California Treasure: Conserved

Jepson Prairie Preserve is owned and managed by the Solano Land Trust, the Nature Conservancy and an active docents group. It is a living laboratory for University of California researchers and students as part of their Nature Reserve System and a treasure for the public who come to enjoy the flush of wildflowers, birds and open spaces. The Preserve supports a strong docent program to educate the public on the value of this undisturbed sample of the state’s natural prairie system, leading tours in the spring months. It is open for visitors year-round.

In a small corner of Northern California’s central valley, parched brown fields lie tucked between gently rolling farmlands. For 5 months of the year, the area is pleasant but unremarkable. Surrounded by small towns and agriculture, most people drive by without knowing about the treasures lying just over the fence line.

Then, coming over the rise in early spring after the winter rains, you’ll see a transformed panorama of lush-green Purple needlegrass meadows and riotous patches of bright yellow Goldfields and Yellow Carpet, Mariposa lilies, and sky-blue Downingia. It is a place that for the best views and most interesting photographs one has to tread carefully and lie on one’s belly in the soft grasses.

I am fortunate to live in an area rich with protected natural spaces, including this local and unassuming flat grassland in California’s Central Valley, the Jepson Prairie Preserve. This small reserve (634 hectares) protects the best remaining undisturbed sample of one of California’s most interesting and unique natural ecosystems of clay-pan vernal pools and native forb and bunchgrass prairie habitats, and is refuge to a surprising number of rare and endangered endemic plants and animals.

Vernal Pool Goldfields (Lasthenia fremontii). Jepson Prairie Preserve, April 2018.

Collecting water in the same location since the last ice age, Jepson Prairie comes alive from February through May. The playa lake Olcott fills with water and then birds, salamanders, shrimp, and insects, and the land is covered with tiny ground-growing flowers that bloom in successional waves around the vernal pools.

In early California history, vernal pools and native bunchgrass prairie habitats could be found across the Great Central Valley. Today, only a small fraction of those habitats survived the millions of people moving into the state. The extensive system of vernal pools supporting millions of migrating birds was plowed and planted into the rich agricultural lands we know now.

American avocets (Recurvirostra americana) feeding on invertebrates in Olcott lake, April 2018. This playa lake provide an important layover for migrating birds, especially critical now because they have lost their extensive feeding grounds along the Central Valley which have been converted to agriculture over the past century.

By protecting this unique ecosystem, Jepson Prairie Preserve provides wetland habitat for millions of migrating waterfowl and wading birds. It supports over 400 species of plants – of which 15 species are rare and endangered, including Bogg’s Lake hedge-hyssop, dwarf Downingia, Baker’s navarretia, Colusa grass, and Solano grass.

Included in the list of 5 rare, threatened and endangered animals protected by the reserve is the Delta green ground beetle which is known only from the 10 square-mile area surrounding Jepson Prairie. Also endemic and endangered are vernal pool fairy shrimp, Conservancy fairy shrimp, vernal pool tadpole shrimp, and the California tiger salamander, which emerges with the rains and quickly reproduces before the next dry season which could last for years.

The stunning waves of flowers attract spring visitors and docent tours, but perhaps just as importantly the flowers support solitary ground bees. University of California research has shown an incredible diversity of bee species endemic to vernal pool habitats. They synchronize their life-cycles and are vital cross-pollinators to the succession of vernal pool flowers including Yellow Carpet, Meadowfoam, Goldfields, and Downingia (UC Davis Natural Reserves link). Some of these bee species are single species pollinators and rely on a specific species of flower found only near vernal pools.

All of these plants and animals rely on a carefully evolved and dependable timeline of rain, blooming, feeding, breeding and migrating. The climate crisis has recently been changing that fine-tuned system. The Jepson Prairie area now has unpredictable periods of high heat in the spring, rains in summer, more frequent years-long droughts, and unusual cold spells in the late spring and summer, even snow in the nearby, low-elevation coastal range. Fortunately, through the work of dedicated volunteers and generous land purchases, the unique ecosystems of Jepson Prairie are being protected and managed to preserve the remarkable plants and animals that have adapted to these harsh cycles of plentiful or scarce water availability.

I am hopeful the Jepson Prairie Preserve will survive and thrive through the changing climate with its strong system of support from the Nature Conservancy’s visionary land purchase in 1980, Solano Land Trust’s management and stewardship, the committed docents, and the inclusion of the Preserve in the University of California’s system of natural reserves.

For more information visit the Jepson Prairie website, or see the excellent field guide produced by the Jepson Prairie docents “Jepson Prairie Preserve Handbook” to learn about the natural history, geography, plant and animal species, cultural significance, and conservation of this area.

A Western Meadowlark (Sturnella neglecta) singing from a Jepson Prairie Preserve fence post, March 2021. In the background lies the dry lakebed of Olcott lake. In a normal year during the month of March, this area would be brimming with water and migrating birds.

Photos by Kathy West, ©2018 and ©2021.

Strikingly Beautiful and Behaviorally Fascinating

White-tailed tropicbird (Phaethon lectures)
White-tailed tropicbird (Phaethon lepturus) Kathy West

Glowing brilliant white in the early morning tropical sun, graceful and balletic, I’ve recently added the white-tailed tropicbird (Phaethon lepturus) to my list of all-time favorite bird species for both their beauty and their interesting behaviors.

After photographing the birds every morning for almost two weeks on the coast of Bermuda, it would only take the sound of their courtship call for me to be rushing for my camera. I was addicted to watching and photographing their interesting behaviors as they renewed their monogamous bonds after being solitary nomads at sea for most of the year.

The mornings on the coast of SW Bermuda are quiet and radiant. Dark clouds (and rainbows!) are often on the horizon and the water glows a turquoise blue as the sun breaks around the cliffs.

White-tailed Tropicbird (Phaethon lepturus)
White-tailed tropicbird (Phaethon lepturus) in morning light. Kathy West

Tropicbirds have striking white feathers, but in the soft, early light they reflect the color of the water on their wings and bellies. Later in the day, when the sun is stronger, the feathers have a burnished luster.

White-tailed tropicbirds
White-tailed tropicbird (Phaethon lepturus). Wings and belly reflect the turquoise color of the ocean. Kathy West

Biology. Tropicbirds can remain at sea for indefinite periods and can stay in the air for remarkably long periods of time. In the air these birds have a tern-like flight pattern with rapid wing-beats, but they also exploit their long wingspan and streamlined body shape to attain impressive altitudes by soaring upwards on rising thermals. While resting at sea, tropicbirds float on the sea surface, due to their waterproof plumage, and will take to the air again after powerful beats of the wings and thrusts of their webbed feet.

White-tailed Tropicbird (Phaethon lepturus)
White-tailed Tropicbird (Phaethon lepturus) hovering.  Kathy West

Quite graceful in the air, the tropicbird’s short, weak feet and backward-set legs cannot support their body-weight, limiting movement on the ground to an awkward shuffle with their webbed feet and by stabbing the ground with their sharp bill and hefting themselves along.

Mating. White-tailed tropicbirds have a intricate, ritualized courtship display – flying together, one bird slightly higher than the other and cocking its head to keep the lower bird in view, they synchronize their wing beats as they fly high into the clouds all the while chirping a distinctive call. As they climb, the bird above dips its elongated tail down and the bird below bends its tail upwards until they touch. Once they reach the apex of their climb, as high as 100 meters, they break apart and fly separate ways, only to repeat the pattern. No, they don’t mate in the air, but they do renew their bonds and come to the same nesting site each year to mate and lay a single egg.

White-tailed tropicbirds
White-tailed tropicbird (Phaethon lepturus) in courtship flight.  Kathy West

White-tailed tropicbirds
White-tailed tropicbird (Phaethon lepturus) touching tails in courtship flight. Kathy West

White-tailed tropicbirds
White-tailed tropicbird (Phaethon lepturus) in courtship flight. Note the upper bird’s visual tracking of the lower bird. Kathy West

White-tailed tropicbirds
White-tailed tropicbird (Phaethon lepturus) in courtship flight. Green blue color on underside is a reflection of the turquoise water. Kathy West

Nesting. A single egg is laid and incubated by both the male and female at intervals of 13 days for around 40 to 43 days. Tropicbird parents use their large, webbed feet as an important heat source when incubating the egg.

Once hatched, the chick is largely left alone in the nest while the parents forage out at sea. It is at this time that the chick is most vulnerable to attacks, particularly from adults of the same or different species, which are looking for nesting sites. The single chick fledges after around 2 1/2 months in the nest, and join the adults in wandering as far as 1,000 kilometers out to sea in search of favorable feeding grounds. (1)

Although not strictly territorial, there is sometimes fierce competition for the best nesting sites and there may be bloody fights between birds, with stabbing, slashing and the interlocking of bills.

Juveniles. Often I saw 3 birds flying together. However, only 2 birds took part in the courtship flights. The third bird may have been a previous season’s offspring. White-tailed tropicbirds lay only one egg per season and juveniles take 2-5 years before reaching sexual and physiological maturity (2). This extended period may be needed to develop efficient methods of feeding and locating prey or for development of mating behavior and claiming a territory. The juveniles can be identified by a yellow bill that turns orange as they reach adulthood.

White-tailed tropicbirds
Juvenile (yellow bill) white-tailed tropicbird (Phaethon lepturus). Kathy West

Feeding. When at sea for most of the year, the birds hunt during the day, diving with a rapid, vertical, spiraling plunge from 15–20 meters for flying fish and squid, and rest at night floating on the water. I observed them hovering (fishing?) above the coastal waves – they would swoop down and often get drenched with splashing ocean water, flying off and shaking themselves like a dog after a swim. They would also hover in front of the rocks and along the cliffs, perhaps feeding on the small crabs and periwinkles. Since adult Bermuda crabs are one of the main predators for their chicks (besides introduced cats and rats), it would be ironic if they were eating tiny crab hatchlings.

White-tailed tropicbirds
White-tailed tropicbird (Phaethon lepturus) hovering. Kathy West

White-tailed Tropicbird (Phaethon lepturus)
White-tailed tropicbird (Phaethon lepturus) feeding along coast. Kathy West

White-tailed Tropicbird (Phaethon lepturus)
White-tailed tropicbird (Phaethon lepturus) hovering. Kathy West

White-tailed tropicbirds
White-tailed Tropicbird (Phaethon lepturus). Kathy West

White-tailed Tropicbird (Phaethon lepturus)
White-tailed tropicbird (Phaethon lepturus) hovering. Kathy West

Distribution. White-tailed tropicbirds live in tropical areas and have a very complex life-cycle, scattered over deep, open ocean waters in the southern Indian Ocean and western and Central Pacific, as well as tropical and sub-tropical parts of the Atlantic Ocean and the Caribbean. They use pelagic areas for feeding and oceanic islands, such as Bermuda and the British Virgin Islands, for breeding. In the fall and winter (October–February) ranges extended as far west as North Carolina in the US and as far east as the mid‐Atlantic Ridge.

White-tailed tropicbirds
White-tailed tropicbird (Phaethon lepturus). Kathy West

Conservation. The white-tailed tropicbird is protected by law at most key breeding sites, and has benefited from a number of conservation measures. On Bermuda, where the bird is the national symbol and known as the “long tail”, artificial nesting sites have been built into the sides of quarries, increasing the amount of available nesting habitat. A dedicated campaign to remove rats in Puerto Rico by trapping and poisoning has seen a significant increase in breeding success.

With a warming climate and sea level rise there has been increasing storm damage to nesting sites for the white-tailed tropicbird. Climate change may play a negative role in successfully raising chicks – both in the stability and safety of the nesting sites and in the abundance of food.

White-tailed Tropicbird (Phaethon lepturus)
White-tailed tropicbirds (Phaethon lepturus) flocking off nesting cliffs, Whale Bay, Bermuda. Kathy West


  1. The breeding biology of White‐tailed Tropicbirds Phaethon lepturus at Cousin Island, Seychelles. Phillips, NJ. Ibis Vol 129(1) pp10-24, 1987
  2. Breeding of White-tailed Tropicbirds (Phaethon lepturus) in the western South Atlantic. Leal GR, Serafini PP, Simao-Neto I, Ladle RJ, Efe MA. Brazilian J of Biol no76(3) 2016