Endangered Species in California

Adult condors stand at 3 to 3.5 feet and weigh 17 to 25 pounds. Males are generally slightly larger than females.

Males and females are similar in appearance. Adult condors have a mostly bald head and neck. The skin of the head and neck is colored in shades of pink, red, orange, yellow, and light blue, and becomes more intensely pinkish orange during times of excitement and during the breeding season. Feathers are mostly black except for white underwing linings. Juvenile birds have dusky black feathered heads and bodies with limited white underwing linings. At hatch, chicks have light pink and orange skin and are covered in off-white down which is quickly replaced by gray down. 

California condors have a wingspan of about 9.5 feet.  Unlike birds of prey, condors do not have sharp talons capable of killing or grasping objects. 

• California
• Nevada
• Arizona
• Utah
• Baja California in Mexico

• This sliding map is sourced from eBirds, and these data points are condors' appearance locations recorded by citizen scientists.
• The left sliding map is the dataset recorded before 2010.
• The right sliding map is the dataset recorded after 2010.
• By comparison, even though the amount of recording is larger than that before 2010, the range of the condor's habitat is still shrinking, where they are mostly located in natural refuges.

Lead poisoning presents a major risk to condors currently. Lead ammunition, when discharged from a gun and striking an animal, tends to fragment into numerous small pieces that disperse throughout the body. Condors and other scavengers, while feeding on these carcasses, unintentionally consume these lead particles. Accumulation of sufficient lead in their system can lead to poisoning and potentially fatal consequences for these birds.

Microtrash ingestion is a major cause of mortality in condor chicks. In their initial six months, they rely solely on food provided by their parents, including regurgitated meat and bone chips for calcium. Unfortunately, adult condors occasionally mistake small trash items like bottle caps for bone chips and feed them to their chicks, leading to fatal consequences if consumed in large amounts.

The salt-marsh harvest mouse (Reithrodontomys raviventris; SMHM) is endemic to the San Francisco Bay Estuary, and is found generally only in the marshes surrounding the Bay.  The SMHM is small, about 10 grams, and probably lives less than a year in the wild, on average.  The species was listed as federally and state endangered by the U.S. Fish and Wildlife Service and the California Department of Fish and Wildlife in the early 1970’s due to habitat loss, as over 90% of the historic marshes in the San Francisco Estuary have been lost or altered. 

Salt-marsh harvest mice are known to eat leaves, seeds and stems of a variety of plant species and are considered to prefer pickleweed and salt grass, as was noted in the 2013 recovery plan. In 2019, researchers recorded salt marsh harvest mice in Suisun Marsh eating insects, including beetles and amphipods, as well as leaves, seeds and stems from a variety of both native and non-native plant species. This suggests a more flexible diet than previously thought. The northern subspecies can drink sea water, but prefers fresh water. The southern subspecies can't live completely on sea water, but it prefers moderately salty water over fresh. In general, they adapt to the nearby environment and rely heavily on the local food resources.

For decades, researchers believed that the salt-marsh harvest mouse (SMHM) was almost completely dependent on tidal marshes dominated by pickleweed. Over time, they found SMHM in other habitat types, such as diked and/or managed marshes, and marshes dominated by plants other than pickleweed. Researchers also recorded SMHM moving into adjacent upland habitats during high tide events. Over the years, captures of SMHM have been correlated with a variety of different plant cover types, heights, and structures, but a taller, complex mix of plants with abundant pickleweed and fat hen seems to be highly preferred by the SMHM.  Today, it is understood that the habitat use of SMHM is more flexible than biologists believed in the past.

The SMHM has historically been most threatened by habitat loss.  The vast majority of the tidal marshes that existed in the San Francisco Estuary and Sacramento-San Joaquin Delta have been filled, diked, or otherwise modified or destroyed.  Marshes that remain are smaller, fragmented, and isolated.  These degraded marshes support smaller populations of SMHM that have little to no genetic connectivity, which is a large threat to the continuity of the population. Left is the raster map of salt-marsh harvest mouse predicted habitats based on the data of 2016.

The SMHM has been addressed in two separate USFWS federal recovery plans, the California Clapper Rail Recovery Plan and the Recovery Plan for Tidal Marsh Ecosystems of Northern and Central California. These plans outline threats to the species, actions that should be taken to help the species rebound, and criteria that must be met for the species to be down-listed from Endangered to Threatened, or de-listed completely. The original recovery plan recommended protecting large existing marshes, restoring diked marshes to tidal action, restoring upland transition zones, performing research on human activities that could impact habitat, performing research on marsh accretion and erosion dynamics, and to perform habitat management. 

The male toad will choose a spot near a river or water bank where he will make mating calls to attract a female toad. They mate in an amplexus position, and the female toad returns to the location to lay her eggs by the water. The eggs are laid in a two-row formation with an average of 4,700 eggs.

Arroyo toads have a beautiful call compared to other Anurans. Their call is known for being a long, fast, musical trill that typically lasts about 10 seconds. Although their sound is unique compared to other Anurans, some insect and other toads make similar sounds such as the cicada (Cicada spp.) and the redspotted toad (Bufo punctatus). To the untrained ear, such calls may sound identical, but the essential difference lies in the pitches of the calls, helping experts distinguish singing arroyo toads from other species.

Since the arroyo toad can be found along the coast of central California to Baja California, Mexico, toad populations occupy different locations, often constrained by elevation. In central California, toads can be found in foothill canyons and intermountain valleys where low-elevation hills reside as well as second to fifth order low-gradient streams. In southern California and Baja California, toads can be found in coastal planes and some deserts with rivers and streams in proximity.

The total estimated breeding population is less than 3,000 individuals. In 1994 when the species was listed, only six of the 22 extant populations south of Ventura were known to contain more than a dozen adults. It has been extirpated from an estimated 75% of its former range in the U.S.

The most important threats to the arroyo toad stem from human activities. These activities include encroachment by agriculture, construction of roads, off-road vehicle use, grazing by livestock and mining. All can result in substantial habitat destruction and/or alteration of river hydrology. Other smaller threats are due to introduced non−native predators such as bullfrogs and predatory fish, non−native invasive plants, drought, wildfire and wildfire suppression, unseasonal water releases from dams, and light and noise pollution from adjacent developments.

The arroyo toad has been the subject of litigation related to its conservation status. Conservation initiatives are in place to mitigate the decline of the arroyo toad. In 2000, developer Rancher Viejo, which wished to build on a site that the toads used as a habitat, sued the  Secretary of the Interior  over whether the department was constitutionally authorized to apply the  Endangered Species Act  to prevent the development in order to protect a species that never crossed state lines. The developer's challenge to the law failed, but in his dissent to the ruling then-Judge and later-Chief Justice John Roberts famously expressed his puzzlement that "regulating the taking of a hapless toad that, for reasons of his own, lives its entire life in California constitutes regulating ' commerce...among the several states '."