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Green Hairstreak Corridor Workday

July 19 2014

I'm fascinated by the butterfly people - the citizens working to protect biodiversity inside the city. The Green Hairstreak Corridor are the first group I'm going to join and work with. (All $ contributions go to Nature in the City -

July 19 2014


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Name: Amber Hasselbring
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Debriefing Stage

Students at San Francisco State University have conducted a Green Hairstreak Corridor Assessment for Nature in the City. Professor Barbara Holzman, PhD, supervised students Melissa Haas, Jessica Amidjojo, Jonti Shepherd, Tatiana Manzanillo, Josh Nuzzo, Joy Querida, and Adriana Austin in their work.

Three of the students, who pioneered the study in 2012, chose to repeat their efforts again in 2013. Nature in the City is incredibly grateful to Barbara and her students. Their comprehensive assessment makes possible a more educated perspective as Nature in the City plans for the future. This student work helps us set monitoring protocol accurately helps us to assess the success of the now 12 habitat sites.

Overall, the students noted an increase butterfly population from 2012 to 2013, and with more students, they were able to monitor 12 sites up from six in 2012. At a site in the center of the Corridor (14th & Pacheco), the students noted that the butterfly population almost doubled since 2012.

Students also created a very useful map with 100 meter diameter circles measured from the center of each habitat site. This distance is roughly how far a butterfly flies from its original habitat.

The map is intended to help determine the connectivity of the corridor. The students concluded that adopting new sites at the northern tip and southern areas (to connect a successful site at 15th & Quintara site an original population at Hawk Hill) would be even more effective at sustaining the butterfly population and assuring their survival.

In addition to strictly adhering to visits to the corridor when conditions were right for the butterfly, the students also noted vegetative cover, sex, and butterfly behavior: basking, taking nectar, mating; and condition, and whether the butterflies were fresh, faded, or with bird strike.

Due to organizational constraints at Nature in the City, the students began their 2013 survey at the end of March, when the first butterflies were seen in mid-January. In effect, last year’s study may have missed the height of flight season.

In addition, in 2012, the students surveyed the corridor for just two months, most likely at the height of flight season, making the data a little difficult to compare. In 2014’s study, Nature in the City is working to prepare the students well in advance of flight season, from January through May.

The students conclude their assessment with this:

"In conjunction with Nature in the City, [this] data can be used by future San Francisco State University students and other groups doing research on the corridor, such as monitoring the butterfly's populations and assessing the current state of the habitat sites. Further research on the corridor will provide data essential to the conservation of the Green Hairstreak butterfly within San Francisco's ever-changing urban environment."


I've told this story to so many people. Really amazing!

We're excited too. Thank you for helping to spread the word!

Mission Underway

Then plant the natives. Mark them with a flag for monitoring (and easy watering for neighbors).


More buckwheat (and others) to plant.


Most of the Workday group worked on this site. Weeding.


An area they had recently planted. Watering and maintenence is done by neighborhood volunteers.


This is great! The same thing is being done in Norway to keep the bees around.

A few other species that they'd planted. ____ daisy?

Preparation Stage

Dune Buckwheat. This is the main plant Nature in the City is planting for Green Hairstreak habitat.


Here are the results from a recent BioBlitz in the area, that the Nerds for Nature crew ran:

Photo via Mr. Wolf on iNaturalist:


Worth reading this whole interview with Liam O'Brien about how he became a lepidopterist:

"ES: You almost have your own creation myth about how you took up with lepidoptery.

LO: It was down the street from here, in the Duboce Triangle. I had just come back from New York, where I did Les Miz for three years, and I was like, get me the hell out of New York City. I had a weird career as an actor. I had a lot of success, a career people would dream of, but I never had an emotional investment. So I got cast to replace Garret Dillahunt in Angels of America. And where I was staying, there was a window facing the back and this butterfly flew into the yard and it was a tiger swallowtail, which is this huge new project I have now. That’s oddly serendipitous, 15 years later. But it’s only in retrospect I can look at that moment and see the change: 180 degrees. Theater was waning. I don’t miss it at all. It was a lot of stress."

Amateurs FTW!

Expedition Background

The Green Hairstreak Corridor was started by Liam O'Brien. The story of how he got involved (after a long career in the theatre) is quite good. Bay Nature wrote a wonderful article:

Nature in the City continues his work, and now organizes the workdays to maintain the corridor. I'm going on Saturday to learn more.