The Parrots of Silicon Valley: An Ecologist’s Perspective

First there were the Pirates of Silicon Valley. Then there were the wild parrots of Telegraph Hill. And now, the parrots of Silicon Valley. *Dun dun dun*

Corny Bay Area references aside, I grew up in the sleepy Silicon Valley suburb of Sunnyvale, and on occasion I would hear the ear-piercing shrieks of big flocks of birds. My mom told me they were parrots, and I never put much thought into it. It never even occurred to me that parrots are not native to California, or anywhere in the US (unless you count the extinct Carolina parakeet). I always knew them as the noisy green birds that would sometimes fly across our neighborhood. Fast forward many years, and I had since forgotten about the birds. Then just a while ago, when I was visiting home and hung out with my friend at nearby Las Palmas park, we were suddenly mobbed by dozens of the parrots, and once again, the ecologist in me became just as excited about them as I had been for just about every animal as a little kid.

I returned to the park the morning after, as eager as an intrepid explorer in the Amazon rainforest (only I was at the heart of a heavily urbanized area known for its tech industry and less so its animals), and brought out my DSLR camera, ready to document the spectacular parrots that somehow carved out a little niche here in Silicon Valley. Sadly, the cries of parrots were now all but absent, save for one individual too far out in the distance for me to capture on camera. Where could they have gone? Then it dawned on me, they must be out foraging during the daytime! I had seen them the day before resting on trees at the park just before dusk, which also made sense since I used to see them flying en masse during the day. The aptly named Las Palmas Park must be the perfect place for them to roost, what with all the nonnative palm trees that it has.

I found myself back at Las Palmas a few days later, this time in the late afternoon, and my intuition had paid off. There the parrots were again, dozens of them squawking and flying about from tree to tree. Success! A couple hundred photos later, and I came home ecstatic and with one more reason to love my hometown. Even in the heart of the tech industry, I was able to find natural (or introduced) beauty in the form of my one true love: wildlife.

*Warning: the following contains science!*

The predominant species of parrot in Sunnyvale is the mitred parakeet or mitred conure (Psittacara mitrata, or is it P. mitratus, or Aratinga mitrata? Seems like scientists can never agree on scientific names). Found in the Andes Mountains from Peru through Bolivia to Argentina, the noisy mitred parakeet has a green body that is lighter in color on the breast, a slightly mottled red head, and a white ring around its eyes. It is similar in appearance to its relative, the red-masked parakeet (Psittacara(Aratinga?) erythrogenys), though the red-masked is smaller in size, has a more solidly red head, and noticeable red on its shoulders. In its native range, the mitred parakeet resides in forests and woodlands, though in its introduced range, it occurs mostly in urban parks. Like many other parrots, it feeds on fruits, seeds, and nuts. It typically gathers in very large flocks outside of the breeding season, and raises its young in tree cavities. Due to its popularity as a pet, escaped mitred parakeets have established populations in Florida, Hawaii, and California, such as the ones that I saw. In the Bay Area, they are most commonly found in Sunnyvale, though they are slowly expanding into other nearby cities such as Campbell, Cupertino, and Mountain View, to name a few.

The mottled red color on the head is a telltale sign of the mitred parakeet.
The introduced parakeets seem equally happy in the conifers as they are in the palm trees.
A great example of urban ecology: despite being an introduced species, this mitred parakeet is making itself at home eating conifer seeds, which might not make up much of its original diet back home. Also, hummingbird!
Palm nuts are another favorite food of the mitred parakeets.

The mitred parakeet, being an introduced species, provides a great opportunity for ecological studies. Unfortunately, there has been surprisingly little research on its introduction into the US. You think scientists would find such an exotic species warranting further investigation, especially in regards to how it adapts to such a foreign environment, and its impact on other forms of wildlife in the area as well as the ecosystem at large. It would be really neat if the parrots here develop a slightly different morphology from their kin back home to help them adapt to a novel environment. Despite extensive searching, I came across very few, if any, papers describing the introduced parrots in California. This paper here (https://www.westernfieldornithologists.org/archive/V28/28(4)%20p0181-p0195.pdf) talks about the population status and distribution of parrots in Southern California. However, the paper was published back in 1997, and much could have changed since then. Besides, it wouldn’t have helped too much with understanding the Bay Area parrot population anyway.

Yet another point of concern is the role the mitred parakeet, as well as other introduced parrots, could play in West Nile virus (WNV) transmission. Although WNV only transmits through the bite of infected mosquitoes and not through dead infected birds, I learned through my former position as a WNV dead bird hotline operator that certain species of birds are good indicators of the distribution of the virus, parrots possibly being one of them. If anything, there is a chance that they could serve as an effective host reservoir for the mosquitoes to feed off of, thereby increasing the incidence of WNV. Yet, this has not been looked into at great detail, so who knows?

What is interesting about the parrot populations of the Bay Area is that although mitred parakeets are the dominant species in the South Bay, the famed parrots of Telegraph Hill in San Francisco are overwhelmingly red-masked parakeets. Is there a reason why these two closely related species dominate in one area yet are less widespread in the other? It could simply be that San Francisco escapees just happened to be mostly red-masked parakeets and established themselves as the dominant parrot species there, whereas South Bay escapees were predominantly mitred parakeets. Even then, this possibility warrants further investigation, and unfortunately, no one really knows exactly when escaped parrots established themselves in the area. If anything, data would have to be gathered from pet stores for the past several decades on what species of parrot were sold in what area, which doesn’t sound too feasible, especially considering much of the pet trade is unregulated and undocumented. As of this point, all I can assume is that a mixture of random chance and certain environmental differences allowed one species of parrot to outcompete the other in their areas, through a process of competitive exclusion. If that were the case, then I would have to delve deeper into the literature as well as do a comparative life history study between the two species to further confirm this suspicion.

Despite the clear divide between both areas, there are definitely mitred parakeets living in San Francisco, and red-masked parakeets living in the South Bay. In fact, the two parrot species have been observed congregating in mixed flocks in both areas. Conversely, in the wild, they have separate, non-overlapping ranges. The red-masked parakeet ranges west of the Andes from western Ecuador into western Peru, whereas the mitred parakeet ranges east of the Andes from central Peru through Bolivia into northern Argentina. At the closest ends of their range, they are about 100 miles apart, separated by the Andes Mountains. Excluding infrequent migration to both sides of the Andes, it can be assumed that the mitred parakeet and red-masked parakeet rarely interact in the wild. That they regularly come into contact here in the Bay Area presents so many fascinating questions: what are their interactions like? Does niche differentiation occur to allow them to adapt to slightly different parts of the environment and coexist together? If so, can we expect to see morphological changes as a result of their coexistence, further enhanced by them adapting to the environment here?

From here comes one of the most intriguing and significant questions of all: what about hybridization? Amazingly, there have been documented sightings of hybrid mitred/red-masked parakeets. Birders are able to identify the hybrids, as they have color patterns that are an intermediate between both species. Since their native ranges don’t touch, this is not only a rare occurrence, but also unprecedented! Despite being similar species, both species still likely behave slightly differently from each other in the wild. Were there any prezygotic, namely behavioral, barriers that had to be overcome for them to successfully mate with each other? Depending on how females choose mates, certain problems could arise. What if the females choose mates by call, and both species had a different call pattern? How would the female recognize a male of the other species as a potential mate? Additionally, does interspecific mating occur between both sexes of each species? If so, would the resulting offspring be different, like tigons and ligers depending on whether the tiger or lion parent were the mother or father? Or does the interspecific mating only work with one sex in each species, such as how mules are produced only through a male donkey and female horse, whereas the reciprocal crossing is much more rarer? And what about the hybrids themselves? What is the prevalence of hybrid offspring here? Are they fertile or sterile? Do they display hybrid vigor and have adaptations from both species to allow them to doubly succeed here? Or are they weaker than either species and represent a dead-end genetic sink, fertile or not?

There could potentially be a hybrid among this group of mitred parakeets.

In conclusion, there are an innumerable amount of questions that come with the mitred parakeet’s introduction to the Bay Area. To even begin any investigation into this subject matter, I would have to do extensive literature review to better understand the mitred parakeet’s biology in its native range, then conduct even more extensive field observations to observe their behavior, catch them using mistnets to gather morphometric measurements as well blood/tissue samples for genetic and disease testing, and subsequently raising feral parrots to perform behavioral/mating trials. I can only imagine this study would take many, many years and thousands, if not millions, of dollars to do. Of course, this is not very feasible, and even though many people find parrots beautiful, I doubt NSF would be willing to fork over that much money just to have someone study an introduced, non-endangered species that has little known impact on the environment here (the operative word being “known”). Even though I may never get all my questions answered, the fact that I have so many questions to ask just from a few days of observing the parrots as well as a couple internet searches to get more insight is great practice for my budding ecologist skills. Whenever I become a professional ecologist, I’ll still ask these same questions, just on different systems with native wildlife that actually require conservation. Until then, check out this map I’m making to document the spatiotemporal range of Bay Area parrot populations and potential parrot roosting sites! Whether or not you’re as interested in wildlife biology and ecology as me, you still have to admit that parrots are pretty awesome creatures.

“Bye bye, now!”