Archivos de diario de mayo 2016

16 de mayo de 2016

2016 Sudden Oak Death (SOD) Blitz

NOVEMBER 3, 2016
Here is an excerpt from an email sent out by SOD Blitz (

"2016 statewide infection levels were double those recorded in 2015. 2016 results showed many new outbreaks including multiple trees in San Luis Obispo County, Mount Diablo (Contra Costa County), the cities of Piedmont, Hayward, and Ukiah. SOD was also better established in West San Mateo and Santa Cruz Counties, and in the Peninsula East of Highway 280. These outbreaks are all on bay laurel trees and it may take years for oak mortality to show up: this is why preventive management should be investigated now in these areas."

OCTOBER 11, 2016
The results of the 2016 SOD Blitz have been posted. Of the 30 samples I submitted, 6 tested positive, 22 tested negative, and 2 seem to have been missed in the processing step. I'll have to see how to rectify the latter. The positives were all found in Wildcat Canyon - some in Upper Wildcat Canyon, and some on Wildcat Loop Trail.

NOTE: The reason the leaves have to be DNA tested is because there are other diseases that mimic SOD.

SATURDAY, MAY 14, 2016 (4 HRS)

I participated in the 10th annual Sudden Oak Death (SOD) Blitz, focusing on Rancho San Antonio OSP. A one-hour training session was held at the Los Altos Hills Town Hall Council Chambers. Matteo Garbelotto, Ph.D. from U.C. Berkeley presented the training. Cindy Roessler was there to assist in training, assign trails to volunteers, and answer preserve-specific questions. After the training, we hit the trails.

Today I collected samples from 10 infected California Bay Laurel trees and filled out a data sheet for each sample envelope, including latitude/longitude coordinates captured from the SODmapmobile app. I covered the following trails: Coyote, Farm Bypass, and a section of Wildcat Loop Trail through the canyon.

Issue: it was hard to determine how far 100 yards was out in the field, especially with counting healthy vs. infected trees along the route. I counted at least 300 footsteps between samplings, unless there was an area where a lot of oak trees have died, then I sampled near there regardless of where the last sample was taken.

SUNDAY, MAY 15, 2016 (7.5 HRS)
I continued collecting samples for the 10th annual Sudden Oak Death (SOD) Blitz. Today I collected 20 samples from infected trees. I covered the remainder of Wildcat Canyon, Upper High Meadow, Wildcat Loop Trail (from the Vista point to the bottom of Wildcat Canyon), Farm Bypass, and Lower Meadow.

Total infected trees sampled: 30
Infected Bay Laurel trees counted along the assigned route (includes sampled & non-sampled trees): 148
Healthy Bay Laurel trees counted along the assigned route: 142
Total Bay Laurel trees examined (I didn’t examine any tanoaks): 290

There were literally hundreds of Bay Laurel trees along my assigned route. There are several groves of bays, each containing dozens of trees in Wildcat Canyon. It was impossible to count and examine all of them in the time allowed. I did my best to choose representative trees.

• Because of all the rainfall this year after (5 years of drought) the number of infected trees is expected to increase substantially.
• Infection can affect 50% of a bay laurel tree’s leaves, or only one. Infected leaves usually appear on the lower branches.
• Results will be posted on October 1, 2016.


Publicado el mayo 16, 2016 12:13 MAÑANA por truthseqr truthseqr | 2 observaciones | 2 comentarios | Deja un comentario

22 de mayo de 2016

Recording Bird Calls

Since my camera is not capable of photographing most birds, I decided to try my hand at capturing bird calls instead. I spent all day yesterday working out the procedure and trying to edit several audios I recorded last week.

Instructions for Converting Video to Audio

  1. Make a video with your camera.
  2. Copy the video file to your computer.
  3. If the file is not in *.wav format, convert it to *.wav using
  4. Launch Audacity (you can download Audacity for free) and edit the file as follows:
    4a. Trim the beginning and end of the recording. Only leave a 3 sec leader and trailer.
    4b. Edit out the noise by using High Pass Filter set to 48 dB, 1000-1500 Hz
    4c. Normalize your sound recording so that the loudest sound from your target species reaches a level of -3 dB. By setting the peak level of your recording to -3 dB, you’ll be creating a sound file that is consistent with the thousands of sound files archived at the Macaulay Library. To amplify your recording, go to the “Effect” menu, select “Normalize,” and then change the number in the “Normalize Peak Amplitude (dB)” to -3.0 dB. The minus sign is important, so be sure to include it!

  5. Save as *.wav file.
  6. Upload to SoundCloud (create an account, if you don't already have one).
  7. Add the sound clip to your observation in


  1. Here's a cool video that shows you how to edit a bird recording using Audacity:

  2. Here are some references for recording bird songs with a smartphone:

  4. Here's a nice guide to editing bird recordings with Audacity::

It's amazing how much background noise there is that we're seldom aware of. Some of my clips had airplane noise that was impossible to filter out without distorting the birdsong. Today I tried to capture bird calls when airplanes were not overhead, and I had a really tough time of it. Planes fly over Rancho San Antonio literally every few minutes in a constant stream of noise. Today, in addition to the commercial flights in and out of SFO, there were military planes taking off from Moffett Federal Airfield every few minutes (and those guys are LOUD). And in between the airplanes, there were crowds of people, a burbling stream, traffic noise from Hwy 280, and my own footsteps and breathing to filter out. By the time the planes and other distractions faded away, the birds were long gone.

Now I have an even greater respect for birders who record sound, and I'm in awe of those who create those gorgeous photos on the Audubon and AllAboutBirds websites.

I realize my audio clips are not that great, but I'm hoping that the purpose of is to record information about the occurrence of species in time and space, and not necessarily about the perfection of photographs and audio clips.

I must be crazy for trying to record bird sounds at Rancho, given all of the above. A secluded place away from humanity would be much better, but this is where I hike & volunteer, so I'll give it my best and hope to improve with time and experience. Also, not many bird observations have been posted in iNat for Rancho, and I know there are dozens of species present throughout the year.

My audio collection:

Publicado el mayo 22, 2016 08:29 TARDE por truthseqr truthseqr | 4 observaciones | 0 comentarios | Deja un comentario

30 de mayo de 2016

More About Bird Recordings

I've been working with bird recordings, as time allows, for a few weeks now. I'm feeling some time pressure, because SoundCloud allows a one-month free trial subscription and then it charges $10 per month, which I can't afford right now. Time is running out... [NOTE: So far, SoundCloud hasn't charged me for using the upload service, and it's been 3 months, so I'm hoping the monthly fee doesn't apply to what I'm doing.]

I've learned how to edit out the annoying airplane noise using the High Pass Filter option in Audacity. I usually set it to: Rolloff=48 dB; Cutoff Frequency=1000, which works pretty well for most recordings. Sometimes there are annoying camera clicks that I haven't worked out how to eliminate (sometimes I cut them out, if they don't interfere with the bird sounds and timing).

Identifying birds by sound alone (when you're just a novice like me) is very hard. Sometimes I can supplement the sound recordings with photos, but my photos tend to be small and blurry when the bird is far away (i.e., most of the time). This is taking much time and patience, but I'm learning a lot about birds, and becoming familiar with those in this area.

Publicado el mayo 30, 2016 04:57 TARDE por truthseqr truthseqr | 8 observaciones | 0 comentarios | Deja un comentario