An inventory of loss on the Los Angeles River

The city weighs revitalization of an unruly river, since transformed into a concrete ditch.

 

Yellow-billed Cuckoo (Coccyzus americanus) In the early 1900s, the western yellow-billed cuckoo (Coccyzus americanus) was a common sight in the lower LA River Basin, where it nested during the summer among dense cottonwood and willow groves. But by the 1950s, its habitat was gone. Today, the cuckoo is a state and federally listed threatened species, and studies are underway to determine if habitat restoration could encourage the bird’s return.
Roberto (Bear) Guerra
In the early 20th century, the unruly Los Angeles River supported a diverse ecosystem. But as the city grew, the river became problematic, prone to destructive winter flooding. After particularly devastating floods in the 1930s, a plan was set in motion to channelize the river, and by 1960 its verdant habitat had been transformed into a massive concrete ditch. This was the final blow for many species that once swam, soared and roamed in abundance along the river. After the concrete set, few would be seen here again.

These images, then, represent the erasure of incredible diversity and beauty from the collective memory of Angelenos. But they also hint at a possible future for the city, which is currently debating a river revitalization effort. Though the river will never again flow in its natural state, some habitat restoration may allow for the return of animals that have sought refuge elsewhere. Given the city’s history of putting development before preservation, it remains to be seen what direction revitalization will take. But if we can remember what was lost, then certainly we can imagine what might be again.

Yellow-breasted Chat (Icteria virens) The yellow-breasted chat (Icteria virens) is a California “species of special concern.” While the bird is still seen occasionally during the summer breeding season, its numbers have been declining for many years, primarily due to the loss of the dense, shrubby riparian vegetation that was once abundant along the banks of the river channel.
Roberto (Bear) Guerra
Arroyo chub (Gila orcuttii) Though none of the seven native species of fish can still be found in the channelized stretches of the LA River, the tiny arroyo chub has managed to survive in greatly reduced and fragmented populations in some of the river’s lowland tributaries. Today, it is listed as a CA Dept. of Fish and Wildlife Species of Special Concern, but because it seems to be the most tolerant to the drastic changes wrought by channelization, the fish is often mentioned as a candidate for re-introduction in the river, if the habitat to support it can be restored.
Roberto (Bear) Guerra
Western Pond Turtle (Actinemys marmorata) The western pond turtle was the only native turtle species that would have been found in the LA River before channelization. While there are some non-native turtles, mostly introduced by the pet trade that live in the river today, the Western pond turtle has been completely extirpated. It is now a California "species of special concern."
Roberto (Bear) Guerra
Blue grosbeak (Passerina caerulea) Though the blue grosbeak (Passerina caerulea) is not generally a species of concern due to its relatively stable numbers and wide range in the United States and down into South America, it is declining in Southern California. Currently on the conservation group California Partners in Flight’s watch list, it is only occasionally seen in the LA area during the summer breeding season, and only where it can still find woodlands and brush near the few remaining soft-bottom stretches of the river.
Roberto (Bear) Guerra
Northern Harrier (Circus cyaneus) The northern harrier is currently a California “species of special concern.” Known as the marsh hawk in the early 20th century, it was a common breeding visitor to the marshy grasslands in the lower river basin. But by the 1940s, the wetlands habitat where it nested had all but disappeared.
Roberto (Bear) Guerra
American Ribbed Fluke Snail (Pseudosuccinea columella) A study of the freshwater mollusks of the LA River from 1984 to 1992, by C. Clifton Coney of the Natural History Museum of Los Angeles County, describes finding “overwhelming evidence that paints a picture of near extinction of an entire freshwater species,” compared to studies from the early and mid-1900s. At the time of Coney’s work, the American ribbed fluke snail was still present in small numbers, but today it is believed to be extirpated.
Roberto (Bear) Guerra
Stephens’ Meadow Mouse (Microtus californicus stephensi) While still found in some of the undeveloped upper reaches of the LA River Basin, the Stephens’ meadow mouse (also known as the California vole) is greatly reduced in number and extirpated from urbanized areas. It is currently listed as a California “species of special concern.”
Roberto (Bear) Guerra
Gray Fox (Urocyon cinereoargenteus) Before the massive urbanization of the LA River Basin over the last century, diverse populations of mammals, including a number of predators, wandered freely along the banks of the river. Though there were reports of a small population of gray foxes near the LA River at Griffith Park several years ago, the animal is now primarily limited to undeveloped areas in the nearby San Gabriel and Santa Monica mountains, where it can still find the native rodents that it preys upon.
Roberto (Bear) Guerra
Bank swallow (Riparia riparia) As suggested by its scientific name, Riparia riparia, which means “of the riverbank,” the bank swallow nests in the sandy lowland banks of the river and in bluffs near the coast. Once a regular summer visitor, it is now considered extirpated from all of Southern California due to the channelization of the LA River and the development of the coastal bluffs.
Roberto (Bear) Guerra
Side-blotched Lizard (Uta stansburiana) The side-blotched lizard was once widespread in some of the dry habitats around and across the basin. In a recent study, herpetologists from the LA County Natural History Museum determined that habitat fragmentation due to urbanization has caused there to be only a few remaining populations on the floor of the L.A. Basin and these are physically, and therefore also genetically, isolated from each other.
Roberto (Bear) Guerra
Pacific Lamprey (Entosphenus tridentatus) Now extirpated from the LA River Basin, the Pacific lamprey once migrated from the sea into the river and nearby streams, to spawn when the waterways were swollen during the winter wet season. Today, it is categorized by the U.S. Fish and Wildlife Service as a “species of concern.”
Roberto (Bear) Guerra
Western Toad (Bufo boreas) Perhaps no animal is as emblematic of the decline of native species in the decades following channelization as the western toad. One of the neighborhoods adjacent to the soft-bottom Glendale Narrows section of the river is still known as “Frogtown,” for the swarms of young toads and Pacific treefrogs that hopped through the streets each year until the 1970s. Today, toads and frogs are rarely to be found.
Roberto (Bear) Guerra

Note: An earlier version of this story incorrectly stated that the Yellow-billed Cuckoo is a federally listed endangered species; it is, in fact, a threatened species. 

Access to specimens courtesy of the Western Foundation for Vertebrate Zoology and the LA County Natural History Museum.

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