Wildlife Immigrants

by Mark Goldschmidt

Some native wildlife species have found ways to make their lives in our patchy “natural” environment of yards, streets, and open spaces. Skunks, coyotes, raccoons, and blue jays thrive here. But non-native wildlife species introduced by humans, intentionally or unintentionally, have found niches in our urban ecosystem, too.

Opossum aka: PossumDidelphis virginiana

For many early settlers in Southern California, hunting supplied an important part of the diet. Native raccoon, rabbits, squirrel and deer, were relished, but southerners missed the possums they had enjoyed back home. So opossums were imported as “game” early in the 20th century and the population has taken off. I’ve never heard of anyone eating a back yard opossum, but “roast possum and ‘taters” was celebrated in the South.

The Virginia opossum migrated from South to North America when the gap between the continents closed about 2.8 million years ago. The opossum is the only marsupial on our continent, with a native range through Mexico and the southern US. It is a peculiar beast. It bears its young less than 2 weeks after mating; they are tiny, the size of a bee, and must “swim” to the mother’s pouch through the fur of her abdomen. Once arrived, each locks on to one of 13 teats where they remain for two months. When it gets too crowded, the pups exit the pouch and cling to the mother’s back as she forages. Opossums’ reproductive setup is fascinating: the male has a bifurcated penis, and the female a bifurcated vaginal tract and two wombs. Two other odd facts: the opossum’s body temperature is much lower than other mammals and it is immune to snake bites.

True omnivores, opossums forage at night on insects, slugs, snails, insects, fruits, nuts, small animals including lizards, snakes, frogs, birds and their eggs, rats and other small mammals. In our environment, they have little fear of people, and are famous for using pet doors to access a meal. In urbanized Altadena they den under stairs, garden sheds, beneath houses, and in wood piles.

Possums are classified as “non-game animals”, and may be controlled by any legal means if found to be pests. In fact, the little creatures are not normally destructive of plants or gardens. They do possess sharp incisors and can injure cats, dogs or people if attacked and cornered, but they usually avoid confrontations, most famously by “playing possum” They They do this very convincingly, tongues hanging out and a suppressed heart rate — they really do look dead. In Altadena their chief predators are coyotes, bobcats, and automobiles.

Red Crowned ParrotAmazona viridigenalis

Simpson’s Garden Town, a sprawling garden center that covered several acres on Colorado Boulevard in East Pasadena, was a wonderful bazaar featuring landscaping supplies, fishponds, a flower shop, lawn mower shop, pets, and aviaries full of exotic birds. In 1959 the whole place burned, and in the conflagration the aviaries were thrown open to save the birds –– among them an unknown number Red Crowned parrots, ancestors of the flocks that now inhabit the San Gabriel Valley. Another origin story credits a plane load of poached birds that escaped around the same time. These parrots, native to north-eastern Mexico where they feed on tropical seeds and fruit, have thrived in our suburban environment with its rich variety of introduced plants and few predators. (There are other species of feral parrots in Southern California, but the Red Crowned are by far the most abundant.)

Currently an estimated 3,000 inhabit the San Gabriel Valley, well known to us as the raucous flocks foraging in our treetops. California flocks exceed numbers in their native range where they are endangered due to habitat destruction and poaching for the pet trade.

Red Crowned Parrots mate for life, breeding high in trees in natural hollows or woodpecker holes, where they raise 3 or 4 fledglings a year. Parrots reach maturity at 5 years, and live 30 to 50 years,. With no serious predators, the flocks promise to keep growing. Intensely social, they vocalize constantly when flying, and sound almost human as they “talk” while foraging.

Exotic, colorful and amusing to watch, the red-headed green birds are enjoyed by many; others are annoyed by the cacophony. It certainly must be unpleasant to live under the trees where flocks roost each night. A 1964 LA Times article “Wild Parrots Cause Squawk in Pasadena” started out: “A policeman’s bullet silenced Friday the squawking of a wild parrot, and thereby touched off another round of controversy over the birds who have inhabited a residential neighborhood here for seven years.” There had been dozens of complaints about the roosting birds at Glenarm and El Molino Avenue  ––  perhaps shooting one bird encouraged the flock roost elsewhere.

However one may feel about them, these birds have found their niche in our environment. Barring disease or a new predator the population will increase and spread.

PeafowlPavo cristatus

The first peacocks were brought to the San Gabriel valley by Lucky Baldwin sometime in the 1880s to ornament his showplace, Rancho Santa Anita. Descendants of the original flock continue to inhabit the site, including the Arboretum and much of Arcadia. Andrew McNally kept peacocks and other exotic birds at his 1890 house on Mariposa (site of AH’s 2022 Holiday Party), possible precursors to Altadena’s current feral flock.

Peacocks — male peafowl — are magnificent creatures; their tails (called trains) are a wonder of nature, and make up to 60% of the 8 to 12 pound body weight of a male., yet they are able to fly quite well. Although native to tropical India, they tolerate cold weather, even snow, and have no problem finding plenty to eat and trees to roost at night in Altadena. Peacocks have a lifespan of 15 to 30 years, they are polygamous and a female can raise as many as 20 fledglings per year.

Our local peafowl are domestic birds gone wild. They don’t fear humans,  and while beautiful to look at, they are no fun to live with. The frequent cry — more of a scream — of the males can carry up to 5 miles. They wreck gardens, poop everywhere, hang out on roofs where they damage shingles and tiles. When they see their reflection males will frequently attack it with beak and spurs, and can seriously scratch a shiny car.

Peacocks are large, formidable birds, and while they will do their best to flee danger, they can be vicious when cornered. They have few predators in Altadena, just coyotes, bobcats and perhaps the occasional large dog. They are reputed to be delicious but no one I know would kill and eat one. Dressing and cooking instructions can be found on line (they are notoriously difficult
to pluck).

If a flock has invaded your yard, spraying them with water may drive them off.  Squirt them enough, and they might move on to someone else’s yard. Feral peafowl are listed as an invasive species and are not protected. If you have a problem with peacocks, don’t call County Animal Control, they do not deal with nuisance fowl.

Eastern Fox Squirrel Sciurus niger

There are four species of squirrel native to California, but the one that has completely  taken over in Altadena’s urban ecosystem first arrived in California when some were intentionally released in the 1920s at a Veterans Home in the San Fernando Valley to amuse the residents. This is the Eastern Fox Squirrel. In fact, there must have been multiple introductions, because their range now extends to many other western states where they are non-native and invasive. California grey squirrels still inhabit the oak woodlands on the urban fringes of Altadena, but are rare to non-existent in urbanized areas.

These rodents are outstandingly agile, fun to watch as they take breath-taking leaps, chase each other around tree trunks, sit upright on alert, or flick their tails and chatter atop fences. On the minus side, these little guys can be real pests, which you’ll know if you’ve ever seen a squirrel tear through a fig tree taking a bite out of every fruit before throwing it to the ground. They are also disliked for their habit of invading attic space where they gnaw on wiring and cause significant damage.

Eastern fox squirrels make dens in tree hollows, or nests of leaves high in trees, where  a female bears two litters of an average of 3 pups each year. They are fairly solitary animals, not playful but highly territorial. With few predators they are very successful in Altadena. Raptors probably get a few, as do automobiles, but these squirrels are too wary, alert, and quick to fall prey to most cats or dogs.

Tree squirrels are listed by the California Department of Fish and Wildlife Code as “a game mammal” which may be hunted with the proper permit. The exception is our Eastern Fox Squirrel, which may be trapped and killed as a pest. It can certainly be eaten –– like the possum squirrel is savored in the South. The Joy of Cooking had recipes and directions for dressing and cooking squirrel up until the 1975 edition.

CatsFelis catus

Ancestor of our domestic pets, the African wild cat began hanging out with people around 8,000 years ago when agriculture was invented. Stored grain attracted rodents, rodents attracted the cats, their natural predators, and a symbiotic human/cat relationship developed. Extremely effective predators of rats and mice, as well as beloved furry companions, cats have accompanied humans throughout the world. In most environments, cats don’t really need humans; strays have led to populations of feral cats worldwide that have devastated wildlife and even whole ecosystems in places they were introduced, especially island habitats.

In Altadena feral cats form an important component of our urban wildlife ecosystem; in fact they been players in its development since its founding when our desiccated outwash plane evolved into agriculture, then into suburb. Cats keep a lid on the rat population, reducing the likelihood of a population explosion. Cats are also prey for our larger predators, coyotes and bobcats. Unfortunately, all cats kill birds and other animals we would rather keep around, like moles and lizards.

Feral cats often live in group dens called “colonies,”  sometimes supported by people who feed them. When I moved to Altadena years ago, a colony nearby was fed by an elderly neighbor. The colony disappeared after she died, but there are still strays in Altadena and will be as long as there are rats.

An ongoing movement to trap feral cats, neuter, vaccinate, and release them back into urban areas (called Trap Neuter Release or TNR) is active in LA and nationwide. The idea is to develop and maintain a stable, healthy population of “community cats” to keep the rodent population under control. Proponents of TNR have claimed success in some cities; they point out it is better to have non-breeding, healthy community cats than untold numbers of feral diseased ones. Furthermore, felines provide non-toxic rodent control. The movement has its skeptics, including some scientists who have studied TNR, and the Audubon Society. The fact is that it is  impossible to eradicate either cats or rats, and  they both play important roles in our urban ecosystem.

Tree Rat, aka Black Rat/ Roof Rat/ Wharf RatRattus rattus

Everywhere humans go, so go rats. In many ways, rats and humans are alike. Like us, rats are omnivores and generalists, they thrive on all kinds of food and adapt to many environments. Rattus rattus has followed people for centuries, hitching rides on ships throughout the world (thus one common name “wharf rat”). It is believed they came to Europe from Asia along Roman trade routes, eventually unleashing repeated human tragedies as they and their flea parasites brought the plague. Rats have assisted humankind in our destructive program, modifying habitats all over the world, indelibly altering ecosystems, devouring flora, bird and reptile eggs, and competing with native wildlife for food, often leading to extinctions. (The larger Brown Rat, or Sewer Rat Rattus norvegicus, is also present in the Los Angeles metro area, but its range is near the coast.)

A great climber, the roof rat prefers lairs above ground, but will burrow in the soil if that’s what’s called for, or make a den in a wood pile. They often build nests in trees, but your attic or a similar dry, dark place is better, where they can hang with their buddies during the day, going out to forage at night, often in groups. They are social animals.

Altadena with large trees, irrigated gardens, berry, fruit and nut bearing plants, lots of shrubbery, and older frame houses is prime roof rat real estate. There is such an abundance of forage here that garbage and pet food make up an insignificant part of their diet. Roof rats are great climbers, and will find a way into an attic if there is an opening the size of a quarter; if the opening isn’t quite big enough, they will gnaw to enlarge it. They eat only about half an ounce of food a day, and an equal amount of water — but they proliferate at a great rate, each female bearing 30 or so young in a year. Average lifespan is a bit more than a year.

As prey animals, roof rats are an important component of the wildlife Altadena’s ecosystem, supporting nocturnal hunters including coyotes, raccoons, owls, bobcats and feral cats. For us, they are the most undesirable of neighbors; they invade our homes, eat our food, foul their nests, stink up our attics, and carry diseases and parasites. Yet they are here to stay.

If you need to kill rats due to an infestation, please, never use poison; birds and mammals will consume poisoned carcasses, sicken and die. Poisoning the rats’ natural predators can lead to explosive growth in the rat population.