A Lil’ Rundown on San Francisco’s Invasive Flora and Fauna

The SF Bay Area’s alien animal and plant neighbors are as diverse as the city’s residents… and didn’t chase six-figure salaries to get here.

San Francisco’s green spaces and waterfronts are crammed with a myriad of flora and fauna. We have seals, native dolphins, whales, and even the breathtaking San Francisco garter snake slithering south of SOMA. Not too long ago, there was even a gator living its best life in Presidio’s Mountain Lake.

Interestingly, most of the beautiful species we San Franciscans see on a daily basis didn’t come from here. San Francisco Bay has one of the highest concentrations of invasive species anywhere in the world. And as a self-knighted ecologist, I’ve always found this San Francisco quirk interesting—and sometimes worrisome.

Let’s get to know some of our Bay Area transplants.

The Chatty Cathies of Telegraph Hill

Ahh, the parrots of Telegraph Hill. The omnipresent, emerald-colored parrots are as friendly as they are vociferous. Beguiling, yes. Invasive? Absolutely.

It’s been widely hypothesized (and documented) that these Amazonian invaders were likely once pets until they escaped, having established a healthy breeding population in the early ’90s. Now, some years later, their numbers are growing as well as their home range. No longer are they just hanging out near Coit Tower; they’re branching out to other nearby landscapes in Nob and Russian Hills, and they’ve reportedly been seen as far south as the Mission.

Word to the wise: they’re friendly and Instagrammable, sure, but never feed them. As with (most) wildlife, offering Polly a piece of your Odwalla Bar will only make him or her unnaturally comfortable around other humans. It’s this friendliness that gets animals into trouble in urban areas.

The (Bullying) Bottlenose Dolphins in Our Bay

Little-known fact: Flipper, the charismatic, larger-than-life cetacean we all think fondly of, is an oceanic instigator. Because of warming waters and shifts in maritime currents, bottlenose dolphins are trolling our very own waters off the Embarcadero, a far stray from their Southern Californian home.

The Bay Area, however, is home to a native blowhole-bound critter — the harbor porpoise. Weighing in at no more than a small person, they’re among the smallest sea-dwelling mammals anywhere, having just returned to their endemic Bay Area waters about 70 years ago. (The ’20s and ’30s left the San Francisco Bay and her sister straits gray with pollution, which wasn’t cleared until the mid-’40s.) But now Flipper and Co. are competing with them for space and resources.

We already know that “dolphin rape” is a real thing that makes for viral Facebook videos, so it should be of no surprise to learn that these 200-plus-pound dolphins don’t play well with other marine mammals either (except for humpback whales, apparently).

Just in our Bay Area waters alone, bottlenose dolphins have been documented not only driving out resident harbor porpoises but, in some cases, killing them. Sometimes it’s done by forcing them under, drowning them within minutes. Other times, the act is conducted far more bluntly. Members of the attacking pod literally use their rostrums as battering rams to beat their smaller opponents till they succumb to excessive internal bleeding. Brutal.

All This Damn Eucalyptus

Tired of Eucalyptus bark dirtying your patio or crowding the running paths throughout Golden Gate Park?

As mesmerizing as this iridescent flora is, Tasmanian blue gum — a.k.a. “rainbow eucalyptus” to you and me—was never meant to root in and around our parks and city streets. Towering, knotted, stripy barked, with flowering white bodies that resemble moon jellyfish, these charismatic trees have firmly planted themselves in the San Francisco Bay Area, despite the fact that they come from halfway around the globe.

Back in the 1850s, they were planted for either our area’s burgeoning timber industry or in place of more fragile trees for scenery. Suffice it to say that they not only did well but thrived. In a recent tree census survey, it was revealed that there might be as many as 20,000 of these Aussie sinus-clearing plants in San Francisco proper.

Oh, and did I mention that eucalyptus, unlike other indigenous Bay Area plants, is incredibly flammable? During 2017’s horrendous wildfire outbreaks, gnarly winds and drier-than-average conditions weren’t the fires’ only incubators. Large swaths of this highly ignitable lumber were one of the biggest roadblocks to containing the blazes. Santa Barbara, especially, contains one of the densest populations of eucalyptus anywhere in the state — which only exacerbated the state’s now second-largest wildlife population.

Living With Aliens

In a globalized world, where goods of all sorts are shipped and sent across oceans and continents, I’ve come to terms with a less-than-ideal reality: we just have to make the best out of a bad situation.

Two summers ago, I was tapped to be a “python hunter” in the Everglades during its inaugural season. An acquaintance of mine, who, like myself, had a long history in dealing with large exotic reptiles, joined me for the sponsored outing. That initial 24-hour odyssey ended up being a three-day witch hunt for free-roaming Burmese pythons along moonlit roads. By the end of that trip, we had caught nearly 30 animals and wrestled to the ground this sobering fact: these animals are here to stay.

Like the Asiatic pythons swallowing swamp life whole in the marshlands of South Florida, our invasive species aren’t going anywhere. They’re healthy and breeding and expanding their territories well beyond our backyards. Once a species takes hold in a new neighborhood, it’s nearly impossible to eradicate them—it merely becomes a game of cat and mouse. For better or worse, San Francisco’s alien flora and fauna neighbors are here to stay.

Feature Image: A parrot enjoying blossoms in Sue Bierman Park. (Photo: Courtesy of Flickr via Byron Chin)

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