14 de enero de 2021

January 13, 2021- south side

14 dead newts (0 juveniles), 0 live newts.
January 13th, 2021 (Wednesday) 1:15pm-4:30pm.
Weather: Nice clear day, mid/high 60s. No rain for many days prior.
Other roadkill: 1 large millipede.
Rainfall: MTD 0.47in, YTD 3.62in (per http://www.weathercat.net/wxraindetail.php?year=2021)
Traffic: 55 motor vehicles, 7 parked vehicles, 22 bicycles (actually a fairly quiet day, I was just out longer than the usual two hours)
Midpen study: Pit traps were emptied before I arrived, and there were no roadkill newts in their road sections.

Few newts today; this might be my all-time lowest count (and a sharp contrast to last week when I did the north side after a day of rain). A few fresh/ish, but mostly old or dried-out crackers.

My newt observations for today: https://www.inaturalist.org/observations?on=2021-01-13&place_id=any&taxon_id=27816&user_id=sea-kangaroo&verifiable=any

Newt map:

Ingresado el 14 de enero de 2021 por sea-kangaroo sea-kangaroo | 0 comentarios | Deja un comentario

11 de enero de 2021

Jan 9 - South Side

40 dead newts, 4 juveniles, 0 live newts.
Jan 9, 2021 (Saturday) ~8:45-11:00 am
Weather: Dry and sunny in the mid 50s. No rain for many days.
Other roadkill: Flat skunk GONE!
Coverage: Aldercroft parking to first stop sign
Traffic: 16 cars, very few considering its the weekend.
Zero commercial trucks.
Pit traps: Empty.

Two conversations:

1) Female runner who adores the newts and had a million questions and wanted to know how to help. Asked to take photo of me (!) because of our snazzy vests, so thank you @merav for increasing the public visibility of our project. You might consider arming us with some sort of business cards with a link "for more information and how you can help" since this seems to happen regularly.

2) Friendly chat with the biologist from HTH at the south pit traps. He's a nice guy; went to Cal Poly SLO where he studied burrowing owls. In addition to working for HTH, he's working on his masters at SJSU with a project on red-legged frogs and CA tiger salamanders. He mentioned that the biggest newt massacres he's ever seen occurred when it was raining at night AND there was an accident on Highway 17, which detoured all the highway traffic onto Alma Bridge Road. I'm not sure where you'd find highway closure data, but it might be interesting to try and correlate those dates/times with the bigger mortality spikes we observed from previous years.

Ingresado el 11 de enero de 2021 por anudibranchmom anudibranchmom | 1 comentario | Deja un comentario

10 de enero de 2021

Pacific Newt Roadkill and Rainfall (Jan 2021)

The following charts show Pacific Newt roadkill at Lexington Reservoir and cumulative rainfall amounts (measured in inches) for each of the four migration seasons we've been surveying. We use the Weathercat website based in Santa Cruz for rainfall and temperature info due to its proximity to Lexington Reservoir and its convenient numeric format which is easy to copy into Excel for analysis purposes.

Cumulative rainfall as of Jan 10, 2021 is much lower than the three previous seasons (Figure 2). This correlates with the lower newt mortality we're seeing for these months (Figure 1).

JanRainfall-2

(Updated on Jan 14, 2021.)

Ingresado el 10 de enero de 2021 por truthseqr truthseqr | 1 comentario | Deja un comentario

How to Measure SVL using ImageJ software

The ImageJ software, developed by the NIH, is a freeware tool for analyzing photographs. It is a useful tool for our purposes of measuring snout-to-vent length (SVL) of Pacific newts, especially those that are curved. Here are instructions for using ImageJ to calculate SVL:

(1) Download the ImageJ software from the NIH website: https://imagej.nih.gov/ij/download.html. The download includes a detailed (and somewhat overwhelming) user's guide of all the software's features & capabilities. Don't worry - we only need to use a few simple features.

(2) Make a copy of an iNat newt picture and save it on your computer. To do this:
--> Right-click on the picture in iNat and select "Save Image As..."
--> I use the 8-digit iNat ID as the file name so I can later go back and enter the SVL (snout-to-vent-length) value.

(3) Launch the ImageJ software. You'll see the ImageJ toolbar on your desktop.
(4) Select File --> Open... and open the newt picture.
(5) Right-click the line tool on the toolbar and select "Straight Line."

Analysis-2

(6) Draw a line on the measuring device in the picture (for example, 1 inch). See the yellow line on the ruler below.

Analysis-2b

(7) Select Analyze --> Set Scale... The "Set Scale" dialog is displayed.
--> Enter the "Known Distance" and "Unit of Measure."
--> Click OK.
Analysis-3

(8) Right-click the line tool again, but this time select "Segmented Line."
--> Double-click on the tip of the newt's snout to start the segmented line.
--> Click to place pivot points along the segmented line.
--> Double-click to stop at the newt's vent. Refer to this drawing:
Diagram for measuring snout-to-vent length (SVL)

(9) Select Analyze --> Measure. The calculated length is displayed in the Results dialog box.
Analysis-7

(10) According to the cutoff of 50 mm (2 in) suggested by @tyap and other herpetologists, this newt would be categorized as an adult. In iNat, set the "Life Stage" Annotation to "Adult" and add the Observation Field "SVL" along with the value calculated by ImageJ.

Ingresado el 10 de enero de 2021 por truthseqr truthseqr | 3 comentarios | Deja un comentario

09 de enero de 2021

Jan 9, 2021 - North Side

January 9th (Saturday) 2021 08:15 am -11:34 am
Weather: 42F, mostly sunny

Documented 52 dead newts, 2 of which were juveniles. No live newts observed.
Did not find any dead newts on HTH survey sites since they were ahead of me. They did mention when they passed by that they found a few dead ones and 4 live males in the pitfall traps(all heading towards the water).

Other documented roadkill:
4 centipedes, 1 Jerusalem cricket, 1 moth

Also spotted a dead Western Screen Owl on the road(but it was not due to roadkill, it seemed this one fell out of the sky)

Documented human activity:
Moving Cars: 128
Pedestrian: 52
Bikes: 48
Motor bikes: 1
Trucks: 0
Parked cars: 71

Notes: The road had a lot of traffic today, can be because it was a sunny day but can also because I saw a lot of beginners on the row boats in the reservoir(Introductory session maybe)
3 hikers stopped and asked me about what I was doing. One person said he loves the newt patrol. One person said he had stayed in that area for more than 25 years and he used to see a lot of newts and cottontail rabbits but does not see them as often anymore. And he thought we were doing the lord's work documenting this tragedy. One hiker asked what should she do if she found a dead newt on a trail, I said just leave it as is since we are only documenting roadkill. She thought the HTH buckets were to dump dead newts.

Also I was scanning car tires for signs that deep treads might carry the newts some distance. And in one instance of a truck with huge tires, I found some evidence.
20210109-110714

20210109-110727

Link to all my observations:
https://www.inaturalist.org/observations?on=2021-01-09&place_id=any&q=roadkill&user_id=karangattu&verifiable=any

Ingresado el 09 de enero de 2021 por karangattu karangattu | 9 comentarios | Deja un comentario

08 de enero de 2021

January 7, 2021- north side

98 dead newts (of which 3 were juveniles), 0 live newts.
January 7th, 2021 (Thursday) 10:20am-12:20pm. Meant to get out Wednesday morning but had some knee issues.
Weather: Completely overcast with fog, 54F. Rained the previous afternoon.
Other roadkill: 1 Jerusalem cricket.
Coverage: County parking lot to second stop sign.
Rainfall: MTD 0.46in, YTD 3.61in (per http://www.weathercat.net/wxraindetail.php?year=2021)
Traffic: 23 cars, 14 parked cars, 6 bicycles, 3 walkers. Quietest day in a long time.
Midpen study: Pit traps were emptied before I arrived, and there were no roadkill newts in their road sections.

Hardly any of the newts were fresh, most were rehydrated crackers.
My observations for today: https://www.inaturalist.org/observations?captive=any&on=2021-01-07&place_id=any&subview=grid&user_id=sea-kangaroo&verifiable=any

Newt map (with obvious "holes" where the midpen study plots are!):

Ingresado el 08 de enero de 2021 por sea-kangaroo sea-kangaroo | 6 comentarios | Deja un comentario

07 de enero de 2021

January 6, 2021 - South side

January 6, 2021 (Wednesday), 11:39am - 1:43pm.
Coverage: Aldercroft Heights intersection to first stop sign.

68 dead newts (of which 3 were juveniles), 0 live newts. Many more dead newts found on the side of the road further from the reservoir. A majority were relatively fresh.

Other roadkill: One very mangled, gelatinous creature, which I'm guessing is a frog.

Weather: Mid 50s, mostly cloudy, started to sprinkle as I left.

Traffic: 22 cars; 7 bikes; 3 pedestrians

One of the dead newts was curious, on the side of the road, not flattened or mangled, but belly damaged, and mostly dried hard, almost feels petrified. I brought them home to finish petrifying.

After spending the better part of an hour putting together these observations, and fixing the way-too-many whose locations were bad, my iNat browser tab blew a gasket and I have to start over, so will get these posted when I have another chance.

Ingresado el 07 de enero de 2021 por newtpatrol newtpatrol | 16 comentarios | Deja un comentario

02 de enero de 2021

Jan 2, 2021 - North Side

Conducted survey of North side 08:10 am-10:23 am. Weather was 49F, cloudy with a light drizzle. Rain MTD 0.14 in, YTD 3.29 in per http://www.weathercat.net/wxraindetail.php
Coverage: north part - the county park parking lot till the second stop sign.

Documented 20 dead newts, 1 of which seemed like a juvenile. No live newts observed.

3 dead newts was observed in HTH survey location (Note I have attached another pic in the observation in the style Merav requested, also in the image it mentions which study site it was)
https://www.inaturalist.org/observations/67477476
https://www.inaturalist.org/observations/67477475
https://www.inaturalist.org/observations/67477474

Other documented roadkill: None observed.

Documented human activity:
Moving Cars: 48
Pedestrian: 20
Bikes: 1
Trucks: 0
Parked cars: 23

Notes: I documented dead newts in the study sites on both sides of the road before the HTH team removed it. When I was returning, I met them at one of the sites(site# 3) and the number of dead newts they found on those sites matched the number I had documented. They also said it was strange that they did not see any live newts in their pitfall traps today.(For sites 1 through 3)

A link to all my observations:
https://www.inaturalist.org/observations?on=2021-01-02&place_id=any&q=roadkill&user_id=karangattu&verifiable=any

Ingresado el 02 de enero de 2021 por karangattu karangattu | 0 comentarios | Deja un comentario

January 2, 2021

Jan 2nd, 2021 - Southern Sector
Saturday 9:08-11:20 am: 17 dead newts found, no live newts
Weather - overcast/partial sun. Very light sprinkle for 2-3 min.

I documented 17 dead newts, no juveniles. Most of them were very fresh, others were a bit more weathered, one the color of mud. 12 of the observations were made on the uphill side of the road, 5 on the reservoir side.
Other roadkills: 1 skunk and a banana slug.
Coverage: Southern sector - the Aldercroft Heights to the second stop sign.
Fairly light traffic, when compared to the northern sector - Traffic: 23 cars ( including 2 Ranger trucks, 2 HTH Biologists, 5 bikes, 7 pedestrians, and 2 cars parked by the road.

*Edited to fix date.

Ingresado el 02 de enero de 2021 por joescience1 joescience1 | 3 comentarios | Deja un comentario

01 de enero de 2021

Pacific Newt Roadkill and Rainfall (Nov/Dec 2020)

The following charts show Pacific Newt roadkill at Lexington Reservoir and cumulative rainfall amounts (measured in inches) for each of the four migration seasons we've been surveying. We use the Weathercat website based in Santa Cruz for rainfall and temperature info due to its proximity to Lexington Reservoir and its convenient numeric format which is easy to copy into Excel for analysis purposes.

Notice the relatively low amount of rainfall for Nov/Dec 2020 in (Figure 2). This correlates with the lower newt mortality we're seeing for these months (Figure 1). Also, the HTH population study accounts for some of the reduction, since they have only shared a few observations with us to date from the extremely high mortality sections of the road they've included in their study.

Rainfall-Dec

Ingresado el 01 de enero de 2021 por truthseqr truthseqr | 0 comentarios | Deja un comentario

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