Posted by:
RichardFHoyer
at Sun Sep 28 15:29:57 2003 [ Email Message ] [ Show All Posts by RichardFHoyer ]
RS:
Simply from examining the distributions of the two Contia species, one can surmise difference in habitat requirements. It is another thing to try and pinpoint what those exact requirments may be as you can find what appears to be typical Forest Sharptail habitat gradually transform into typical Common Sharptail habitat all within a dozen meters or thereabout.
As an example, highway 9 winds uphill from the west city limits of Saratoga, Calif. (Santa Clara Co.) about 5 - 6 miles to the summit or spine of the Santa Cruz Mts. that may be about 900 to 1000 ft. elevation where highway 9 intersect highway 35 or Skyline Blvd. Skyline runs north and south long the spine of those mts. and separates Santa Clara county on the east with Santa Cruz county on the west side of that road. There are virtually little to no shoulders along highway 9 with the south side hugging the hillside and covered with trees which thus shades that side of the road. At various points, the north side of the highway is more exposed to the sun and more open brush / grassland habitat occurs at spots along that side of the road and across the ravine and hillside to the north. In those open, grassy areas along the north side of highway 9 and only 50 - 80 meters across the ravine in places with open grassland/scrub habitat, I would expect to find the Common Sharptail (C. tenuis).
In May 2000, I collected two Forest Sharptails along the shaded south side. Across the road over the guard rail under small pieces of junk in the grass habitat I found Ringneck and garter snakes. The road is two lanes. I would put big money that C. tenuis occurs in the open areas just north of that road.
Along highway 35 at 0.5 miles south of the junction with highway 9, I also found a Forest Sharptail at the base of a small cliff under leaf litter. This area was far more open than where I found the two specimens along highway 9. And again, about 50 meters or less south is typical C. tenius habitat.
About 8 - 9 miles south along highway 35 my son Ryan did find C. tenuis on the same side (east) of the road as I found the Forest Sharptail but his habitat was open grass/brush.
I suspect that one would need to obtain and chart specific factors of rainfall, humidity, cloud cover, etc. and compare that with known locality sightings of the two species to possibly characterize habitat requirments. Even then, there probably would be some overlap. Possibly there is a difference between the species for mean temperatures and minimum days at certain temperatures at which eggs will hatch. The Forest Sharptail eggs can possibly hatch successful at lower number and/or with days at certain minimum temperatures than C. tenuis.
Richard F. Hoyer
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RE: Response to Contia questions - RichardFHoyer, Sun Sep 28 15:29:57 2003