Friday, October 17, 2014

An October Farewell to the Blue Ridge Mountains.

Sourwood Fall colors
It is time for our annual migration to Florida so we are bidding a fond farewell to our beloved Virginia Blue Ridge mountain farm.  During the brief interludes in rain over the past week I have been able to catch some typical fall views of this area.  Of course the overwhelming impression one gets now is of the beautiful fall leaf colors.  One of my favorites is the sourwood, a small forest sub-canopy tree in the heath family that has an amazing  combination of red and yellow leaves and sprays of dry whitish fruits.  The leaves actually have a sour taste as the name implies.  

Viburnum rufidulum fruits 
Our rusty blackhaws, a viburnum, are covered in fruits, many of which surprisingly are not yet ripe.  Note that of this cluster of 11 fruits, two are black/ripe, four are reddish and approaching ripeness, and five are greenish and far from ripening.  The use of color to signal birds when fruit is ripe and edible, and the seeds are ready for dispersal, is very interesting since it allows a plant to maximize its seed production.   The process of sequential rather than simultaneous ripening of a group of fruits may also reflect the efficiency of seed dispersal, so that one bird eats only a few and then another bird comes that is going in another direction and eats another.

Autumn meadowhawk (dragonfly)
You normally think that fall is a time when insects decrease in numbers and then disappear when frost occurs.  That is generally true but this beautiful male autumn or yellow-legged meadowhawk is one of the few dragonflies that is characteristic of fall.  It is the latest dragonfly to emerge from its aquatic larval phase and one of the latest breeders. This essentially allows cold-tolerant species to occupy a distinct niche.  

Great spreadwing damselfly 
Banded garden spider captures great speadwing damselfly
The meadowhawk was present with shadow darners and great spreadwing damselflies around one of my fish-less ponds.  The damsels were in tandem and thus breeding. One damselfly, which is a predator on other insects, encountered another larger predator, the barred garden spider, and became a meal.  The food web here was literally the spider web of death!   

Gravid female praying mantis
I also encountered a very large gravid female praying mantis which will soon be laying a capsule that will protect the eggs though the winter.  In most cases the adults die during the winter and continuation of the species is due entirely to the eggs.  This is likely a Chinese mantis, introduced to the US for insect control.  The problem is that the mantis does not limit its predation to noxious insects but eats beneficial ones as well.  

Garter snake
Reptiles are not seen often during the fall as temperatures drop.  This garter snake seemed to be warming itself in a sunny opening in the forest.  I picked it up to admire its colors but you may be unaware that garter snakes actually are mildly venomous!  They have enlarged rear teeth and can chew and deliver a mild neurotoxic venom from the Duvernoy's gland.  It would be harmless to most people unless you were allergic to the secretion.

Female northern yellow shafted flicker
There is a lot of bird activity in fall with migrants passing through.  This female northern flicker was hard at work digging in an old stump looking for insects.  Although flickers occur throughout the eastern US all year, birds in your yard may not be the same individuals in summer and winter.  Canadian flickers may move south into your area and your flickers may move south.  

There is much natural history to enjoy in fall but prepare yourself for the approaching winter and the huge changes to come.
Bill Dunson , Galax, VA and Englewood, FL

Thursday, October 16, 2014

Nature in Some Western Mountain Forests

Whitetail deer feeding in pond_Heron, MT

A bonus of a recent visit to our kids and grandkids that live out west is that I got to experience some wonderful montane habitats in Montana and Utah.  It is not only exciting to see new habitats and critters but to renew a sometimes jaded outlook when one remains a long time in your home place.  We encountered a fabulous forest of ancient cedars along Ross Creek in Montana; such old growth trees evoke an amazing feeling of pristine beauty.  

Black Bear at Amber Bear Inn

Cedars at Ross Creek, MT
Although other nearby forests were made up of spruces, firs and pines of more modest proportions, there were giants of another kind present;  we encountered a huge black bear just outside our room in northwestern MT, and the landlords had many tales of cougars and bears killing their goats.  Whitetail deer were common and several were seen feeding in a pond; this aquatic behavior is thought to provide a needed nutrient, sodium, which is generally lacking in their diet of terrestrial plants.  

Kokanee salmon_Kootenai River Falls, MT

A visit to the Kootenai River falls near Libby, MT, not only revealed a beautiful glacier-fed river but a spawning run of bright kokanee salmon (landlocked sockeyes).  It is thought that prehistoric ice dams may have trapped a population of salmon, preventing their migration to the ocean, and they adapted to this new circumstance and were able to complete their life cycle in fresh water.
Red shafted Northern Flicker,_Midway, UT
Some western birds are distinct species, and others are instead subspecies of a single widespread North American species. The red shafted version of the northern flicker is an example of the latter; this photo of an adult male primarily differs from eastern flickers by the reddish instead of yellowish color of the bases of the tail and wing feathers, and a red instead of black "mustache." 

Stellers jay_Whitefish, MT
Certainly geographic isolation can lead to very distinct far western and high altitude species such as the Steller's jay, which is a brilliant blue with a dark head and crest; this photo was taken in Whitefish, MT.   A jay in Park City, UT, had white marks on the forehead which is indicative of a different population.

Dipper_Cascade Springs, UT
One of the strangest and most appealing of the far western birds is the dipper, a unique swimming songbird.  It is generally difficult to observe closely in fast flowing streams where it lives but we found a group of them inhabiting Cascade Springs in the Wasatch Mountains of Utah  that were habituated to human visitors.  Their peculiar habit of bobbing as they walk is similar to the movement of unrelated spotted sandpipers and waterthrushes  (warblers), which feed along the edges of water; one wonders what the function of this common behavior is.  

Flame skimmer dragonfly_Midway, UT
The most beautiful insect I observed was the male flame skimmer, a predaceous dragonfly, near a pond in the Uinta Mountains of Utah.  As is often the case in dragonflies, the males are much more brightly colored than the females.  This appears to be a means of advertisement by the males who compete for territory and females.  Indeed one guide book describes "Red Baron" aerial battles between males competing for perching sites.  

So when you travel, enjoy the biodiversity of new areas and prepare to be dazzled by the surprising colors, behavior and structure of the new species you encounter.   

Bill Dunson