Dripping Springs TrailDripping Springs Trail, Irvine Ranch 04/07/2013 In January of 2013 a friend invited me to participate in a butterfly survey with the Irvine Ranch Conservancy, which had started the year before. Here I am nine years later and still counting. While each month I enjoy a fun walk with great people and taking photos of the butterflies, I hope my input contributes to restoration and conservation. 

During the pandemic, only the official volunteers from the conservancy were allowed to participate in the survey. I am a 'public' volunteer and therefore could not participate. Additionally, at the end of 2020, there was a fire that hopscotched through the area. Since I have rejoined the butterfly surveys, post pandemic and post fire, I thought I noticed a change in the butterflies. This got me curious. Was it merely my perception or reality?

I requested access to the data and spent the several weeks looking deeper into it than I had planned. This has been a project of my own creation to satisfy my own curiosity.  I think my curiosity is insatiable, but for now I have spent enough effort on it. Since the inception of the surveys there were 6,072 entries, 52 species, and 32,376 individual butterflies counted. From this data I created a five page report summarizing some of my findings, and twenty-seven pages of charts (I learned a lot about Excel spreadsheets).  I then prepared another four page addendum comparing my findings to findings in "The Butterflies of Orange County" by Larry Orsak published in 1977.  I looked at all 52 species on our list. In many cases, the names have changed over the years, both common and scientific, and I had to "reverse engineer" them to find them in Orsak.

A Summary of My Summary

Years 2015, 2016, 2017 and 2019 were banner years in terms of numbers of butterflies for many species. Painted lady - Vanessa carduiPainted lady - Vanessa cardui
Dripping Springs and Limestone Canyon Trails, Irvine Ranch 04/07/2019
Year 2019 was also the year of the Painted Lady. They were everywhere across the state; numbers of Ladies across Southern California soared. I'm not sure of the reason, but those were great years. My mind immediately jumps to rainfall over the winter, but I haven't been able to confirm that theory.

Behr's metalmark - Apodemia virgultiBehr's metalmark - Apodemia virgulti
Dripping Springs and Limestone Canyon Trails, Irvine Ranch 04/07/2019 The ‘500 Club’: These species have had counts of 500 or more individuals in a single year. Behr's Metalmark, Woodland Skipper, Checkered White, Western Pygmy Blue, California Ringlet hit over 500 in multiple years. In 2019 Painted Lady made it for that year. In 2015 White Checkered Skipper hit the 500 mark.

For the species that occurred in greater abundance, I mapped out the flight periods. I could see where some seemed to have only one brood per year while others are multi-brooded. I compared these to those documented by Orsak, and in many cases found similar findings. This has validated many of my observations from the data.  However, I noted that in several cases, Orsak listed that for some of the multi-brooded species, the earlier spring broods were larger, while our numbers indicate the later broods were larger.  I have no explanation, but did note the differences.

Since the December 2020 fire, I notice that numbers and species have changed a bit. I looked at some of our more numerous species. Behr's Metalmarks, California Ringlets, and Woodland Skippers disappeared in 2021.

Checkered White - Pontia protodiceCheckered White - Pontia protodice
Dripping springs to Limestone Canyon Trails, IRC 06/08/2022 Cabbage white - Pieris rapaeCabbage white - Pieris rapae
Irvine Ranch, dripping Springs/Limestone Canyon Trails, 02/02/2020

The interesting changes have been in whites and sulphurs. Numbers of Checkered Whites soared since the fire. Orsak noted that where together with Checkered Whites, Cabbage Whites are more abundant. We see more Checkered whites than Cabbage Whites, but there has been an increase in Cabbage in recent years. We should watch to see if numbers of Cabbage increase over time comparatively.

Orange sulphur - Colias eurythemeOrange sulphur - Colias eurytheme
Dripping springs to Limestone Canyon Trails, IRC 06/08/2022 Dainty Sulphur - Nathalis ioleDainty Sulphur - Nathalis iole
Dripping springs to Limestone Canyon Trails, IRC 06/08/2022
Orsak indicated that Orange Sulphurs are rarely common and are found primarily in lowlands. We only have three months of data in 2022 and Orange Sulphurs are looking stronger than in the past.

While our numbers are not significant, Orsak noted that Dainty Sulphurs are never common. We have seen them more frequently and in increasing numbers recently.

Are these lasting changes? Are these significant? Will we have another 10 years of data to compare to in 2032?

If you are interested in more details or have comments, feel free to leave a comment or contact me.