BCS Mar 2024: Guerrero Negro to Estero San Jose

From 2 to 15 March 2024, I was in Baja California Sur (BCS) with the primary intent of birding from La Paz to Guerrero Negro, a stretch of desert, oases, marshes and bays that I’d spent very, very little time in. My accomplice, neigh, my guide in this adventure was Gerardo Marròn, a skilled ornithologist and good friend living in La Paz. In the album below, photos are ordered as follows, based partly on the interests of my friends: birds, other vertebrates, invertebrates, plants, and finally, scenery. The photos are selected partly for their visual appeal, but some are included because the species is rare in BCS (Bay-breasted Warbler, for example) or are endemic to the area (for instance, the cactus Creeping Devil – gotta love that name – which occurs only on the west side of central BCS). Gerardo schlepped down to the Los Cabos airport on 2 March, and we birded together from 3-10 March. Gerardo then schlepped back to the Los Cabos airport, where I rented a car. Thereafter, which I birded south of La Paz, from Estero San Jose to San Antonio de la Sierra, and was fortunate to be accompanied by Daniel Galindo at San Antonio.

Over the last 30 years, I’d visited BCS over 40 times, largely prowling the area from La Paz to Los Cabos, an area sometimes referred to as “The Cape.” The Cape straddles the Tropic of Cancer and reaches from the sea to mountains towering >2000 meters above. Though the area is generally arid in temperament, it is also subject to tropical storms and hurricanes from July to November, a time during which the air is often laden with moisture. There is some “classic” desert there, but also a lot of thornscrub, and in the mountains, pine-oak woodlands. The coastline is dotted by several estuaries and marshes as well as some exceptionally productive mudflats (nothing is more productive than mud, really). The Cape (which was an island in the past) is inhabited by a number of endemic plants and animals (including birds) and has various patches (usually centered around the presence of water) that attract birds in large numbers, including -- over time -- a spectacular array of rarities hailing from Asia, eastern North America and mainland Mexico (examples include Yellow-browed Warbler, Terek Sandpiper, Swallow-tailed Kite, Flame-colored Tanager, and White-necked Petrel).

To the north of La Paz, the landscape is generally harsher, drier, more foreboding. Parts of the Vizcaíno Desert in the north do not see rainfall for years on end (though the desert as a whole averages 2 cm/year). The countryside there varies from flat and monotonous (in spots, resembling an unkempt gravel parking lot), to hilly and almost lush, including swatches of riotous and fantastical landscape populated by a crazed assortment of cacti as well as yuccas, boojum, and elephant trees. Breezes from the Pacific bring moisture from the ocean, sometimes in the from of dense fog, which not only helps these plants survive, but also encourages their ornamentation by a variety of lichens and bromeliads. However, the Peninsula from La Paz to Guerrero Negro is more than just the Vizcaíno. There are a number of oases thick with palms and marsh-fringed ponds, thornscrub-covered hillsides, and large estuaries. Indeed, BCS has several impressive and globally important estuaries and bays, including Laguna Ojo de Liebre and Bahia Magdalena, that support an astounding amount and diversity of life. Additionally, important to us birder sorts, there are specks of manmade habitats such as golf courses, town parks and sewage ponds, that attract a lot of birds, especially those that normally inhabit far away places.

The most fascinating, intriguing, spectacular and (add your superlative here) place we visited has to be the Guerrero Negro Saltworks. Even the name, Guerrero Negro, is intriguing, meaning Black Warrior in English. Knowing this sent my mind spinning off into a myriad of fascinating fantasies about the area’s origin story. A potential origin story involved Vincente Guerrero, a leader of the Mexican War of Independence and Mexico’s second president; Vincente, who was partly of African heritage, was indeed known as "El Guerrero Negro." The origin of the town's (and saltworks') name, alas, is distinctly more mundane: In 1858, a U.S. whaling ship, from Massachusetts, named Black Warrior wrecked itself in the lagoon, a happy ending for the region’s whales.

Back to the saltworks. They cover 82,000 acres along Laguna Ojo Liebre and produce 7,000,000 tons (or 14 billion pounds) of salt annually, which is 34% of world salt production! This is done by a series of evaporating ponds; the outer impoundments, adjacent to Ojo Liebre itself, are the least saline, and the innermost (which are dry) are 99.3% NaCl, with sunlight and wind removing the H2O from the equation along the way. Those outer ponds provide excellent habitat for brine shrimp and their avian predators, whilst some impoundments have mudflats and saltmarsh; together, these outer areas host enormous numbers of shorebirds, herons, and Eared Grebes. The adjacent Laguna Ojo Liebre is beloved by Brant, Surf Scoter, loons, cormorants, etc. The saltworks and adjacent laguna host 32% of the Pacific Coast population of Marbled Godwits, 32% of the roselaari subspecies of Red Knots, and 68% of the caurinus subspecies of Short-billed Dowitchers during winter! The bird populations of the saltworks are regularly surveyed, but access to the general public is rather restricted; fortunately, Gerardo formerly surveyed there, and with a little (well, actually, a fair bit of) wrangling, he was able to gain our entry.

Our trip had inertia. It was a bit like a steamroller that needed a push-start. On day one, Gerardo and I pushed with all of our combined might, but we were not sure that anything moved. On day two, we gained a bit of traction and could feel those wheels starting to turn. On the third day, well, on that day, it was rolling good, and we knew the ignition was ready to fire up. After that, nothing could stop us as we glided across the landscape, finding rare birds and perusing a fascinating world.

For more specifics on lodging, food, etc – see my trip report on ebird at (copy and paste the part in quotes from https to 213333) ebird.org/tripreport/213333 -- Note, currently the travelogue portion of the trip report has been partly stymied.