A Young Person’s Guide to Exploring Nature By Susan Rothrock Deo
How Did THAT Get There: Pt. 2: Animals
The first time I heard a peacock, we were visiting my husband’s family in India. Their calls here in Palos Verdes conjure up fond memories. Not everyone shares my sense of wonder about peafowl (only the male is a “peacock”). They are like dandelions—a joy to some, a pest to others. Around 1900, the exotic birds were a status symbol for superrich Americans.
In 1880, real estate tycoon Elias “Lucky” Baldwin brought a few back from their native India to wander around his Arcadia estate. When banker Frank Vanderlip bought up the Palos Verdes Peninsula in 1913, he thought it was too quiet. It’s unclear whether it was Baldwin’s daughter or a daughter of chewing gum magnate William Wrigley Jr. who fixed that by sending
Vanderlip two crates of peafowl, but the rest is history. Although peafowl are not native to the peninsula, they are not invasive. Even though messy and loud, they don’t out-compete native species, cause habitat loss or major economic harm.
Scientists are rethinking the term “invasive.” Nonnative species aren’t an army mov- ing in to take over! Every species is trying to live a full life and reproduce. Some- times they’re disruptive to habitat; sometimes they become a welcome member.
Once a nonnative population is large enough to be noticed, scientists can study its environ- mental and economic impacts and decide whether controls are needed. Most species “simply become one more local species with a story to tell,” according to a book published by the Natural History Museum, Wild LA: Explore the Amazing Nature in and Around Los Angeles.
The Catalina fox has lived on Catalina Island for 5,400 years and is an important part of the island’s ecosystem. How did they get there? Did they float across the channel on logs or debris? Did the first Catalina settlers bring them? People brought bison to the island in the early 20th century.
Since 2009 conservationists have used birth control to manage the population. Domestic pigs and goats escaped into Catalina’s wilds, out-competing native species for food. They decimated some plant populations and had to be removed.
Nonnative insects are among the most “invasive” species, especially if they have no natural predators and attack food crops or carry new diseases. The cottony cushion scale found its way to California in the late 1800s. Luckily, scientists discov- ered and introduced its major predator, the Vidalia ladybug, soon after and helped protect our citrus crops. Things don’t always work out, however. The Argentine ant is ranked among the world’s 100 worst invaders. You probably have some within a 100-foot radius of you right now,. They are outcompeting many California ants and have caused a decline in native horn lizards; whose main food is local ants. They also threaten our economy because they “farm” aphids and mealy bugs and feed on the “honeydew” they produce. Aphids and mealy bugs eat beneficial plants and crops. We don’t need more of them!
Even native species can cause problems. For example, we humans are creating the perfect habitat for crows and brown-headed cowbirds. Their ranges have expanded, and their populations too. Crows out-compete some native birds for food and habitat. Cowbirds pose a unique threat. The female cowbird lays her eggs in another bird’s nest and lets that bird incubate them. Her aggressive hatchlings, often bigger than the host birds, out-compete their foster siblings for food and sometimes push other eggs out of the nest. Local songbirds haven’t figured out how to thwart the cowbird’s tactics as birds in other habitats have. Trapping some cowbirds and moving them seems to help.
Native, nonnative, invasive or not, nature is complex and on the move!