24 February 2015

Little has changed over the past ten days; fence lizards basking midday when it’s sunny but no rattlesnakes out when I have checked. The only interesting development was on 19 February, when I found that Female 41 had moved again, this time about 7 m (23 ft) to another smaller log where she was out of sight.

Today, I started collecting data on my Droid smartphone, rather than taking paper notes. Using a program called iFormBuilder, I have been able to create a menu that allows me to record twenty-nine observations of things like where a snake is, what it’s doing, temperatures, other environmental data, nearby flora, etc., mostly by making choices on drop-down menus. When I’m done, it automatically up-links to my computer at home where the data is waiting to be saved in an Excel spreadsheet. This not only helps standardize the data I collect but it saves an unbelievable amount of time by eliminating the need to manually enter data from paper notes. I used a similar system during my 40-month field study of Mohave rattlesnakes (2001-2004) and recorded something like 150,000 data points during more than 3700 encounters with the snakes; if that had been done on paper, I would still be working on data entry!

At 12:17 PM, I found a small unmarked male rattlesnake laying in the sun at the same refuge shared by CRORs 35, 38, 39, 40 and several others. He was captured (CROR45) and processed. At 242 grams (9 oz), he is large enough for a transmitter (the rule is the transmitter should not exceed 5% of the snake’s body mass, so my 9 g transmitters require a snake of 180 g (6 oz) or larger), however, releasing him with a fresh surgery when the weather is likely to be cold for weeks to come is not good. Physiological processes in ectotherms (animals that rely on the environment for body heat rather than making their own) slow way down when they get cool, which includes their immune systems and their ability to heal wounds. So Male #45 will be processed (measured, marked, etc.) and released where he was captured without a transmitter.

Before releasing him, however, I wanted to see if he was the same snake I saw on 14 February, since his body size and rattle looked very similar. But after comparing a photo of his face with my photo of the unidentified snake from 14 Feb, I found that they are not the same animal. In the photos below, note the difference in shape of the margin of the postnasal scale at (1), the speckling pattern of the preocular scale at (2), and the shape just under the eye of the margin of the dark postocular stripe at (3). Of course, there are many other dissimilarities in the photos… bottom line, it’s not the same animal.Compare 45 with UNID

The last development to report from 24 February is that I could not get a radio signal from Male #40. Thinking that he might have left the refuge with all the warm sunny days, I walked around for awhile without detecting his signal, so I returned to the refuge and used the burrow camera to look forCROR40 24Feb15 him. Sure enough, there he was (yellow/blue paint in his rattle). This is the third transmitter to fail prematurely and all are from the same batch of refurbished units (they last a year and, after removal from the snake, are returned to the manufacturer to be rebuilt with new batteries). As I have mentioned previously, the manufacturer very rarely gets a bad lot of batteries which then affects an entire series of their transmitters. The good news is that I have no more of that batch of transmitters. The bad news: CRORs 35, 38, and 39 all have those transmitters in them. Transmitters have already failed in 36, 37, and now 40. Hopefully, I can catch Male #40 basking and catch him before he leaves the refuge – which could be any time, given the unseasonably warm days. I am reminded that one of those transmitters functioned for over a year in the last telemetered rattlesnake at my El Dorado Hills study site, so maybe all of them don’t contain bad batteries. Nonetheless, I will replace the transmitters in 35, 38, and 39 as soon as they leave their winter refuge, rather than waiting for their normal 12-month replacement.

One thought on “24 February 2015”

  1. hey mike! been looking for you for a while to get the info on myths about the mojave green. but simply couldn’t find you. somehow i missed this site. and your site seems to empty?

    glad to see you alive and well. congrats on the MS and new studies.

    i was able to photograph a new green on the 15th. very very exciting. check my flickr website listed.

    if you have a copy of or know how i can download that list of mojave green myths you wrote that would be great. i would like to share on occasion on facebook with those who were chased by mojave greens.

    the wildlife biologist was traveling with works on fort irwin relocation snakes and tortoises in the way of tanks. or guns. or humvees with guns

    latest profile of people who get bit by rattlers: young men, tattoos, t-shirts, from texas who have been drinking.

    great site here!

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