This project collects observations of juveniles found dead on Alma Bridge Road near Lexington Reservoir, Santa Clara County, CA.

"While mortality at any life stage is concerning, juveniles should be of special interest when assessing road mortality and mitigation... because their fate can have a disproportionate impact on population dynamics."(1)

Important: Volunteers, please enter the word "Juvenile" in the Notes or Tags field (or both) so that it's easy to search for and find these juvenile observations. As of this date, it's not possible to search for observations based on Annotations or Observation Fields.

When we first started this project in Nov 2017, we didn't realize the importance of collecting data on juveniles. We started annotating juveniles during the 2019-2020 season and measuring them during the 2020-2021 season.

How to Differentiate Juveniles from Adults:
Tiffany Yap, Ph.D. (@tyap) provided the following info and references:

According to the Amphibiaweb accounts, the smallest recorded reproductive adult was 5 cm/2" in snout to vent length (SVL), though there is variation and average adult size is 6.9-8.7 cm/2.7-3.4 in (SVL). So there is some fuzzy area, but this provides a conservative threshold.

If we estimate the tail length is about the same as the SVL, then total length of smallest reproductive adult recorded is about 10 cm/4 in.

How SVL is Calculated
We're using the ImagJ software app developed by the NIH to measure SVL.

Method:

1. Copy the photo of a juvenile to your computer.
2. Launch the ImageJ software.
3. Select File --> Open and open the picture.

4. To set the scale:
   4a. Right-click the line icon and select "Straight Line."
   4b. Draw a line on the ruler (e.g., for 1 in).
   4c. Select Analyze --> Set Scale... and fill in "Known Distance" and "Unit of Length"

5. Right-click the line icon again and select "Segmented Line."
6. Draw a segmented line on the newt from snout to vent. Double-click to start & end the line.
7. Select Analyze --> Measure to display the newt's measurement.

References:

1. Neglected juveniles; a call for integrating all amphibian life stages in assessments of mitigation success (and how to do it)
2. Diagram for measuring snout-to-vent length (SVL)
3. https://amphibiaweb.org/cgi/amphib_query?where-genus=Taricha&where-species=torosa&account=lannoo
4. https://amphibiaweb.org/cgi/amphib_query?where-genus=Taricha&where-species=torosa&account=amphibiaweb
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