Saturday, January 3, 2009

The Barnyard Brats - Rattlers Again

The barn is big and not currently used by humans or livestock. In this semi-abandoned state, it seems to be a popular place for small rattlesnakes. This posting exhibits the 9 rattlesnakes I have encountered in or near the barn.

Consider this a detective story. Why are there so many rattlesnakes at this location and why are they almost always small-sized? Are the same snakes returning to the barnyard after being chased or relocated? How can we determine if snakes viewed on different dates are the same or different individuals? What will happen next year?

Subject 009
Discovered 10/24/07 while co-worker of Samson & Son ilk was investigating barn for potential salvageable finds. Fortunately, same co-worker had experience working outside and instinctively ran out of barn as soon as he heard familiar buzzing sound. I peeked in barn just in time to see small rattlesnake slip behind one of the ancient cabinets. No photo taken.

Subject 013
Small rattlesnake found 05/12/08 behind garage next to barn. First blotch at top of neck was butterfly-shaped. Captured with muslin butterfly net and relocated approximately 0.1 mile in a northeasterly direction.

Subject 017
Large greenish rattlesnake discovered under picnic table after 5 people had been meeting for one hour around same table to discuss grazing. All 5 meeting participants leapt away from table and brave ranger dispatched rattler with shovel. No photo taken.

Subject 019
Small rattlesnake found coiled up between studs and by screened vent in garage on 05/18/08. Caused serious consternation and disruption of plans to clean garage for the day. Couldn't scoop up snake between studs with round net. Borrowed litter picker tool from ranger office. Rattler successfully eluded capture and slithered behind boxes and beneath shelves with constant rattling for one hour. Eventually captured Subject 019 and relocated 0.4 miles in easterly direction. Second photo taken as snake slithered away at relocation site and shows a blotch broken into two dots near the tail end.

Subject 020
A few hours later on the same day, 05/18/08, while moving heavy equipment on a dolly and precariously nudging a lawn chair out of the way with one hand, discovered another small rattler coiled up at northeast corner of barn by hose. I had spent several hours reading in the same chair at this location the day before. Quickly captured rattlesnake with litter picker tool and stored in sealed container for several hours to determine if any more visitors required portage to remote location on the ranch that day. Released at same location as Subject 019 at 7 pm.

Subject 027
Small rattlesnake discovered at northeast corner of barn near hose on 06/18/08, one month after finding similar-sized rattler at same location. However this snake had a thin white line through the brown blotch between the eyes and the blotch at the top of the neck appeared forked on the top, whereas neither of these patterns were evident in photos taken of Subject 020. Moved 0.1 miles in westerly direction next morning at 6:30 am.

Subject 028
Small rattler discovered 06/19/08 at northeast corner of barn by hose and chair at 18:00 almost 12 hours after releasing similar-sized snake found at same location previous day. Subject 028 had white lines between nose blotches and a split blotch at top of neck similar to Subject 027 and it is highly likely this snake crossed a ravine and returned to the same location by the barn and chair in less than one day. Captured and held Subject 028 for several days to see if any additional rattlers showed up - none did. On 06/22/08, moved Subject 028 in southeasterly direction 0.6 miles. Marked snake's rattle with red spray paint.

Subject 034
Discovered small rattlesnake stretched out on concrete sidewalk at foot of kitchen steps on warm night at 10 pm on 08/11/08. Jumped over snake to get snake tongs in garage; captured that night and released 08/15/08 in easterly direction 0.4 miles (same location released Subjects 019 and 020). Marked rattle with black spray paint.

Subject 040

Discovered by unsuspecting visitors on 10/26/08 as they reached for a decorative horseshoe on large rock outside northwest corner of barn. Visitor was so enamored by horseshoe art (which I had never noticed) that he did not see rattlesnake on same rock until I grabbed him by the shoulder and pulled him back. Small rattlesnake was neatly tucked into notch in sunny rock. Snake had double-forked blotch at top of neck, kidney-shaped blotches 2/3 way down length of tail and small rattle. Snake captured by tongs and net with assistance of wary visitors and relocated 0.4 miles in easterly direction. Marked rattle with white spray paint.

CONCLUSIONS: In at least one case, moving a rattlesnake (Subject 027) a short distance (0.1 miles) probably resulted in it returning in one day (Subject 028). None of the marked rattlesnakes (Subjects 028, 034, 040), which were moved 0.4 to 0.6 miles away, have reappeared at the barnyard yet - assuming that the spraypaint doesn't rub off. Since northern Pacific rattlesnakes give live birth in August through October, and 5 of the 8 small rattlesnakes were found in May or June, these snakes likely were born in a previous year. We, therefore, cannot assume that they were located near the barn because they had been born in that general vicinity and had not dispersed yet. Two gopher snakes were also observed repeatedly in and near the barn during the first consistently warm week in May 2008, and since gopher snakes sometimes den with rattlesnakes (Klauber), it is possible that the barn or some nearby location is serving as a winter den.

The most likely scenario is that the barnyard provides or recently provided suitable rodent prey and sunny basking sites which attract snakes including rattlers. A hardworking crew cleaned up many years of junk in the barnyard 2 summers ago, and a change in tenants on the property has resulted in careful disposal of garbage so as to not attract mammals, and discouragement and trapping of rodents around the house. These actions, along with safe relocation of rattlesnakes over 0.5 miles away, should result in less sightings of rattlesnakes near the barn in future years. Tenants and visitors will be educated to use caution when working in the barnyard during warm parts of the year.

Laurence M. Klauber, Rattlesnakes, Their Habits, Life Histories, & Influence on Mankind, abridged edition, University of California Press, 1982.

Barn photo by Mark Walchuk.

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