Wildlife

Watchable Wildlife on the Guadalupe River
with Ranger Pam

Splitting Hares.
One of the more visible animals seen on the Guadalupe River Trail is the Black-tailed Jackrabbit (Lepus californicus). Jackrabbits are members of the order Lagamorpha, which comes from the Greek words lagos for “hare” and morphe meaning “form”. The order includes hares, rabbits, and pikas. Many people mistake rabbits and hares for large members of the rodent family. Lagomorphs, unlike rodents, have four (4) incisors in their upper jaw (rodents have only two incisors) and Lagomorphs will, for the most part, eat only vegetation while rodents will eat both meat and vegetation.

Jackrabbits are easily identified by their long, black tipped ears, long gray-brown body and large hind legs. Jackrabbits average 3 to 7 pounds in weight and are 17 to 25 inches long. Jackrabbits also have a fairly large tail that is tipped in black and usually carried upright over their back.

The long legs and strong body of the Jackrabbit make then very athletic. Jackrabbits have been measured at speeds up to 40-45 miles per hour and can leap up to 19 feet high in one jump! Besides their speed and agility Jackrabbits rely on their keen sense of hearing to protect them from predators such as coyotes, Red-tailed Hawks, Great Horned Owls, foxes, and bobcats.

Jackrabbits are most active in the late evening, night and early morning. They can be found through out California in open valleys, grasslands and into the foothills and desserts. Jackrabbits are very adaptable and will live in urban areas such as parks, golf courses, and airports. Jackrabbits eat a variety of foods depending on their location and the time of year. Like most rabbits and hares they prefer green grasses, and other small succulent plants. They will also eat leaves, bark, or the seeds of woody plants if needed. Jackrabbits will begin grazing in the evening and continue feeding all night. If there is plenty of food they may only travel a short distance each night. Jackrabbits will frequently use the same route over and over again creating easily spotted paths through the grass. Another unique feature of the Jackrabbit is its ability to go without a source of water. Jackrabbits are capable of surviving on just the moisture they get from the plants they eat. Jackrabbits are typically solitary animals but may come together in groups when food sources are limited.

Breeding season for Jackrabbits is usually from January to August. The female (or doe) will have 2-3 young that are born fully furred, eyes open and able to move about easily within a day. Young Jackrabbits are known as leverets until they are about a year old. A doe can have as many as 5 to 6 litters of babies each year. The doe does not have a burrow or nest but gives birth in a “form”. Forms are shallow bowls, slightly deeper at one end, which the Jackrabbit scrapes out of soft soil under cover of a shrub or other plant. Adult Jackrabbits will also use forms as resting places during day. While the babies are up and active quickly the doe will still nurse her babies for up to 12 weeks after birth.

Hare or Rabbit?
While we call them Jackrabbits, they are actually hares. As a general rule rabbits give birth to blind and hairless babies in underground burrows or warrens. Rabbits will have shorter ears and are typically much smaller and less athletic than hares.

Hares, including Jackrabbits, live in shallow depressions or flattened grass nests and their young are born fully furred with open eyes and able to move about a short time after birth. Rabbits have also been successfully domesticated are frequently kept as pets or raised for rood and fur. Hares are very nervous animals and have never been domesticated.

Black-tailed Jackrabbit (Lepus californicus)
Guadalupe River Park south of Taylor Street.

Do I Smell Something Funny?
Guadalupe River Park is well known by the local bird watching community for its diverse bird population but few visitors realize how many small and midsize mammals call the river park home. You may be even more surprised to find the river, even in the heart of downtown, is home to a thriving population of Striped Skunk (Mephitis mephitis).

The Striped Skunk is found throughout most of California.  About the size of a large house cat these handsome animals sport a black coat with a wide white stripe starting at the head, going down the back to the tail. The tail is thick, full, and bushy and may have additional white hairs. While black and white is the most common color pattern, scientists have documented some variation including seal brown, all white, and yellow.

Striped Skunks are best known for the specialized musk glands found under their tails. These glands are paired and surrounded by strong muscles that are capable of spraying the yellowish colored and extremely strong smelling musk several yards. Striped Skunks can also change the pattern of the spray from a mist like pattern to a more common short stream of larger droplets.  The musk of the Striped Skunk is not only pungent but is a strong irritant to the eyes and ingestion can cause severe discomfort or even death in other mammals.  Skunks use the musk as a defense to protect themselves and their young from predators.

Striped Skunks reside in underground dens and the females will typically have a litter of 5 to 7 young in May or June. The youngsters will gradually start taking short trips out of the den with their mother to learn to search for food and can been seen marching in line behind their mother during these trips into the world

Skunks are primarily insect eaters feeding on grasshoppers, beetles, crickets, grubs and other large insects. In areas where insects are hard to find skunks will eat a wide variety of food such as eggs, mice, voles, fruits, berries, and ground nesting birds. 

While many predatory mammals will eat skunk if food is scarce skunk is not a preferred food item. The largest predators of Striped Skunks are the birds of prey such as the Great Horned Owl, Eagles, and large hawks.

Striped Skunks are active at night. They will begin their active time about 1 hour before sunset and return to their dens about dawn. Striped Skunks are very docile and non aggressive animals. The cost common reason for conflict between skunks and other species, including people, is surprising or cornering a skunk. When surprised a skunk will often display a threat posture where they arch their backs, raise their tail, stamp their front feet and walk backwards. If the other animal or person does not back away, or the skunk feels too surprised to give a warning, the skunk will turn its tail towards the threat and spray its potent musk in defense.

Visitors using the trail just after sunrise or just before sunset may see a Striped Skunk start out on it’s night time search for food. At least one family of 5 young have been seen near the Taylor St. over crossing and several adults have been seen from Coleman Ave. to Alviso.  Like all wildlife, please watch from a respectful distance and never try to handle or capture any animal that appears sick or injured. Please report sick or injured wildlife to the park rangers or animal services.

The Common Merganser  (Mergus merganser)

The Common Merganser is a large, slender diving duck that has a long, thin, toothy bill designed to catch fish.  The Merganser is common along the Guadalupe River and can be easily identified by the unique bill that is also bright orange in color. The male merganser is a handsome fellow in breeding plumage. During the spring he sports an iridescent greenish-black head with a crest, a bright white neck, underbelly and sides with a gray back and tail. The male also displays a black line along the sides of his back.

During the non-breeding times of the year the male will look very similar to the female showing a rusty, brown head with short crest and a white chin. The body will be slate gray with white on the belly and sides.

The female merganser can be identified by her rusty brown head with a short, ragged looking crest, a white chin, slate gray back, wings and tail and white on the flanks an d belly. Like the male, the female has the bright orange, narrow toothy bill.

Mergansers can be found nesting along the Guadalupe River.  A Common Merganser will lay 6-17 creamy white eggs per clutch. The eggs will usually hatch within 28-32 days. The female, who raises the young by herself, typically nests in a large tree cavity. Sometimes the cavity is in an old woodpecker nest or another naturally occurring cavity from a broken limb or other defect in a large tree. On rare occasions a merganser may use an artificial nest box or chose a cavity in hollow log or rock crevice.

Newly hatched mergansers jump from the nest within a day or two of hatching and can swim and dive as soon as they reach the water. Unlike most other birds, the parent mergansers do not feed the babies. Young mergansers start diving and catching their own food right away. The young chicks will start by catching aquatic insects but quickly move up to catching the fish that make up a large part of their adult diet.  The mother merganser will usually leave the young on their own before they can fly. Broods of young mergansers, sometimes as young as two weeks old, will band together after the mother leaves. The Common Merganser is considered migratory waterfowl but can be found most of the year along the Guadalupe River.

Christmas Bird Count in the
Guadalupe River Park & Gardens

The Audubon Society's Christmas Bird Count is an all-day census of early winter bird populations that takes place every year between December 14 and January 5. More than 50,000 volunteer observers across the Americas take part in counting all birds in their particular area. The result is over a century of data on bird populations from North to South America. This data is crucial, as it is used by scientists to monitor bird population changes over time.

For the past three years we, along with the Audubon Society and other volunteers, have completed the census of birds in the River Park from 280 to 880, and in Guadalupe Gardens. Please see the list below for the birds that were counted in 2001, 2002, and 2003.

Wish you could have been there? Don't wait for the next Christmas Bird Count to enjoy the birds, just grab your binoculars and head on down to the Guadalupe River Park & Gardens and let us know what you find! Also, please visit the Audubon Society's website at www.audubon.org to find out more about the birds in our area.

To view the bird count data from this, and past years, click here.

New Guadalupe River Park & Gardens Wildlife Watch!

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Wildlife List

Birds
Fields and Gardens
White and Golden-Crowned Sparrows, W. Scrubs Jays, Amer Robins, Brewer's Blackbirds, starlings, American Kestrels, Black Phoebe, Yellow-rumped Warblers, Ruby-crowned Kinglets, House Finch, Lesser Goldfinch, House Sparrow, Anna's Hummingbird, Northern Mockingbird, California Towhee. 

Riparian (river) Corridor
Those listed above, plus Great Egret, Snowy Egret, Black-crowned Night-Heron, Great Blue Heron, Belted Kingfisher, Mallard, Pied-billed Grebe, Amer Coot, Red-winged Blackbird, Song Sparrow.

Others
Red-shouldered Hawk, Red-tailed Hawk, Peregrine Falcon, Osprey, Downy Woodpecker, Nuttall's Woodpecker, Common Merganser, Townsend's Warbler, Lincoln's Sparrow, Common Yellowthroat.

Fish
Coming Soon

Amphibians
Coming Soon

Identification

Click on the type of animal you would like to identify.

Amphibians & Snakes