• Yellow-crowned night heron from Texas
    This yellow-crowned night heron was photographed in Lubbock, Texas. © Joe Manthey
  • Asian weaver ants from Thailand
    Asian weaver ants dismember the queen of a rival colony in Thailand. © Pipat Soisook
  • Short-tailed weasel from Utah
    This short-tailed weasel in Utah was one of 1,870,000 observations recorded in this year's Challenge. © Adam Olsen
  • Carnival candy slime mold from the SF Bay Area
    These fruiting bodies of a carnival candy slime mold were spotted in the Santa Cruz Mountains. © Ryan Pearson
  • Western fence lizards from the SF Bay Area
    The western fence lizard was the most observed species in Los Angeles County. © Donna Pomeroy
  • Giant electric ray from Mexico
    This giant electric ray—which displays either albinism or leucism—was seen off the coast of Mexico's Socorro Island. © Hector Hernandez

SAN FRANCISCO, CA (May 8, 2023) — In its eighth year, the annual City Nature Challenge—one of the world’s largest community science events—has surpassed 1,870,000 wildlife observations for another record-breaking year! Over the four-day event held last weekend, more than 66,300 people across six continents participated however they could—from attending local wildlife surveys to finding the species in their own homes—to document the wondrous diversity of wild plants, animals, and fungi that share our planet using the free mobile app iNaturalist. From observations of critically endangered and elusive species to sightings of species outside of their known ranges, the City Nature Challenge underscores the power of community science in tracking real-time changes in our planet’s biodiversity—especially in urban areas.

Started in 2016 by the California Academy of Sciences and the Natural History Museum of Los Angeles County as a friendly competition between San Francisco and Los Angeles metro areas, the Challenge has expanded to over 450 cities around the world. This year’s Challenge broke previous observation records, tallying over 1,870,000 observations and recording over 57,200 species worldwide—including more than 2,500 rare, endangered, or threatened species. The highest number of observations were tallied in La Paz, Bolivia, where over 3,000 participants made more than 126,400 observations during the Challenge weekend! This year’s Challenge was made possible by the hundreds of individuals and partner organizations around the globe who empowered their respective communities to safely explore nature in their neighborhoods.

“I'm always excited to see new cities, especially those in new countries, join in the City Nature Challenge,” says Alison Young, co-Director of Community Science at the Academy and co-founder of the Challenge. “This year, we were thrilled to welcome participants from Baku in Azerbaijan, Maputo in Mozambique, Nairobi in Kenya, as well as several cities in Eswatini, India, Rwanda, and Thailand.”

See below for highlights for this year’s City Nature Challenge.

San Francisco Bay Area by the numbers

  • More than 31,900 observations submitted to iNaturalist
  • Over 2,480 observers
  • Contributors averaged 12.8 observations
  • Over 2,850 species documented
  • Most observed species: California poppy (Eschscholzia californica)

San Francisco Bay Area highlights

Highlights from around the Bay Area include an endangered California tiger salamander, two sunbathing western fence lizards, a vulnerable and endemic wild onion, fruiting bodies of cotton candy-like slime mold, a male valley carpenter bee in mid-flight, a pair of Steller sea lions, a watchful great horned owl in San Francisco’s Presidio, an American beaver in the South Bay, and a California newt carefully navigating the forest floor.

World by the numbers

  • More than 1,870,000 observations
  • Over 66,300 observers
  • Contributors averaged 28 observations
  • Over 57,200 species documented
  • Most observed species: Mallard duck (Anas platyrhynchos)

World highlights

Highlights from around the U.S. and the world include an inquisitive yellow-crowned night heron in Texas, a giant electric ray with albinism or leucism near Mexico’s Socorro Island, an Indo-Pacific humpback dolphin off the coast Hong Kong, a playful pair of red fox pups in England, a short-tailed weasel after a successful hunt in Utah, Asian weaver ants dismembering the queen of a rival colony in Thailand, a carefree southern sea otter in California’s Monterey Bay, a dazzling sea slug in New Zealand, a critically endangered buchu plant in South Africa, a desert-dwelling coast patchnose snake in Orange County, and a portly Pacific horned frog in Ecuador.

For Young, the Challenge is not only a source of critical biodiversity data but an opportunity for people to connect with nature and each other. “Slowing down and really seeing how many different species are around you no matter where you are—maybe even finding something you had no idea lived around you—helps to build a deeper appreciation for the natural world.”

About the California Academy of Sciences

The California Academy of Sciences is a renowned scientific and educational institution with a mission to regenerate the natural world through science, learning, and collaboration. Based in San Francisco’s Golden Gate Park, it is home to a world-class aquarium, planetarium, and natural history museum, as well as innovative programs in scientific research and environmental education—all under one living roof. Museum hours are 9:30 am – 5:00 pm Monday – Saturday, and 11:00 am – 5:00 pm on Sunday. Admission includes all exhibits, programs, and shows. For daily ticket prices, please visit www.calacademy.org or call (415) 379-8000 for more information.

About the Natural History Museums of Los Angeles County

The Natural History Museums of Los Angeles County (NHMLAC) include the Natural History Museum in Exposition Park, La Brea Tar Pits in Hancock Park, and the William S. Hart Museum in Newhall. They operate under the collective vision to inspire wonder, discovery, and responsibility for our natural and cultural worlds. The museums hold one of the world’s most extensive and valuable collections of natural and cultural history—more than 35 million objects. Using these collections for groundbreaking scientific and historical research, the museums also incorporate them into on- and offsite nature and culture exploration in L.A. neighborhoods, and a slate of community science programs—creating indoor-outdoor visitor experiences that explore the past, present, and future. Visit NHMLAC.ORG for adventure, education, and entertainment opportunities.

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