Teton Tuesday: Necessary Violence

Ever since civilization happily elevated most of us from the toothier, nutrient-supply side of the food chain, violent aggression has lost much of its practical value to human beings and our society. That is not to say that violence doesn’t continue to propagate itself into our way of life, but for every example of modern violence that would be generally considered warranted and useful to our species, there are ten-fold examples of its costly and often tragic misuse. Even those rare instances where violence is justified are most often just a reaction to another individual or group’s misguided indulgence in the primal bloodlust that still lingers in our DNA despite its diminished value to our species as a whole. This is not true, however, in the animal kingdom. In the woods as in the sea (for predators at least) violence remains the only way dinner stays put. It also plays a key role in the way territories are established, hierarchies are settled, offspring are protected, mates are competed over and key resources are distributed. The wilds of Tejon are no different, and this week we are going to look at examples of the way violent aggression is used by some of our resident wildlife to advance themselves along the pitiless cycle of survival that so characterizes the natural world.             

Young male boars square-off in order to determine a dominance hierarchy that can be used to establish territories and access to females.

 

Nesting ravens attack this red-tailed hawk for threatening their chicks. Notice how the Ravens always try and engage the hawk from above and behind. 

Rival coyotes compete over access to a wild boar carcass.

 

Here a young cougar refines its hunting skills by going after smaller prey. Unfortunately my camera's sensor was too slow to capture this cougar pouncing on a gray squirrel.

Restoration on the Olympic Peninsula

Elwha Dam constructed 1913, slated for demolition 2012. Photo by Larry Ward, Lower Elwha Fisheries Office (2005).

At the core of the Conservancy mission is to enhance and restore the native biodiversity and ecosystem values of Tejon Ranch.  The Conservancy’s Ranch-wide Management Plan presents a number of conservation activities directed at restoring streams and wetlands. We also love to hear about really positive stories of environmental restorations.  Please see this inspirational story of restoration from the Olympic Peninsula.  The Conservancy congratulates and thanks the many, many folks who steadfastly pursued the removal of the Elwha dams!  

World's Largest Dam Removal Unleashes U.S. River After Century of Electric Production

Consider how reaches of the Elwha River such as this might change with increased and punctuated flows, rather than controlled release. Photo courtesy of Elwha Jeff via Wiimedia Commons.

A map of the Elwha River watershed. Image courtesy of the National Park Service via Wikimedia Commons.

Climate Change and Bird Habitat by Tom Maloney, Executive Director

The report on climate change (http://climate.audubon.org/) released today by the Conservancy’s close partner the National Audubon Society reveals distressing trends and projections on the distribution of birds in North America.  The Conservancy shares National Audubon’s concerns over the ecological impacts from climate change and has been working with partners to anticipate the changes.  The Southern Sierra Partnership prepared a region-wide framework (http://www.southernsierrapartnership.org/ssp-framework.html) for climate change adaptation.  Also, Conservancy Board member Dr. Frank Davis and several colleagues are conducting a large scale macro-systems experiment with a couple study sites on Tejon Ranch that seeks to refine our understanding of how important tree species will respond to anticipated climatic changes.  Despite all of the worrisome news, Tejon Ranch’s large size and 6,000 foot elevation range offer a number of micro-climates that may provide refuge to species as they attempt to adapt to changes in climate.  The Conservancy’s conservation planning seeks to ameliorate other stresses to foster the ability to adapt to shifts in climate.

Let's have a look at how researchers are modeling these changes for a few common species on Tejon Ranch:

Golden Eagle (Climate Endangered)- We are lucky to have this iconic species on Tejon Ranch year-round. As climate changes and prey habitat/abundances shift, these amazing predators may not be so common on the property. Click the photo for a map of modeled range fluctuations as a result of climate change. Photo courtesy of Greg Smith www.flickr.com/photos/slobirdr

Western Bluebird (Climate Threatened)- This jewel of the west is one of Tejon's most common and attractive birds. Visitors to the ranch will often see large family groups flying, calling, and feeding with one another. Although their habitat looks secure in California, climate change will likely affect bluebird habitat throughout the West. Click the photo for a map of modeled range fluctuations as a result of climate change. Photo courtesy of Greg Smith www.flickr.com/photos/slobirdr

White-breasted nuthatch (Climate Threatened)- This diminutive denizen of forests throughout North America will likely see some major habitat shifts over the next several decades. Fortunately, due to the elevational gradient on Tejon Ranch, we will likely see this species for the foreseeable future.
Click the photo for a map of modeled range fluctuations as a result of climate change. Photo courtesy of Greg Smith www.flickr.com/photos/slobirdr

Lastly, it is important to differentiate between the climate and the weather.  Dr. Neil deGrasse Tyson does a good job of that in the video below:

WILDLIFE WEDNESDAY: DRAGONFLIES AND DAMSELFLIES

Flame skimmer (Libellula saturata) is one of the more striking (and common) dragonflies on Tejon Ranch. Photo courtesy of Chuck Noble

Late summer in California is often seen as a time of senescence. Hot temperatures and dry conditions conspire to make many plants lose their leaves (drought-deciduous) and force animals to estivate. Fortunately for us naturalists, we can use this time to seek out water sources and turn our attention to insects. In particular, dragonflies and damselflies (members of the order Odonata) present themselves as some of the most colorful, acrobatic, and fascinating creatures around. 

Mesurupetala dragonfly fossil By Daderot (Daderot), via Wikimedia Commons

Part of what makes this order so fascinating is how ancient it is. Fossil records provide evidence that dragonflies and their kin have been on planet Earth since before dinosaurs. According to the University of California Museum of Paleontology website, dragonflies have been around since the Carbonifeous - that is over 300 million years!

Dragonflies and damselflies are also fascinating because of their life history. After hatching from their eggs, dragonfly larvae live underwater as jet-propelled hunters. That’s right- they take water from their mouth and shoot it out of their rear end to generate rapid bursts of movement. Damselflies in contrast will wiggle their abdomens from side to side as a means of propulsion. If their hunting speed wasn't formidable enough, these larvae also have a labium, or lower lip that they project forward in order to catch their prey (Biggs, 2004). It's almost like these creatures are miniature versions of the extraterrestrials in the Alien movies! Members of the order Odonata typically spend extended periods of time in their larval stage. In the case of some species of dragonfly, it can take up to 6-7 years before they find a dry place to emerge as adults. 

Blue dasher (Pachydiplax longipennis) adult perched above the abandoned larval exoskeleton of a larger dragonfly. Photo courtesy of Chuck Noble

Once they emerge as adults, dragonflies and damselflies become aerial hunters extraordinaire. Dragonflies in particular have been observed as having a hunting success rate around 95%! Check out this New York Times article (http://www.nytimes.com/2013/04/02/science/dragonflies-natures-deadly-drone-but-prettier.html?pagewanted=all&_r=0) if you don’t believe it!

One of the biggest factors contributing to their success as hunters is how their flight has evolved. Unlike many other insects, dragon and damselflies can move each of their four wings independently, allowing them to move forward, backwards, and make immediate stops. The two videos below provide some great information about how these can be so maneuverable.

In addition to their incredible life histories, dragonflies and damselflies can be extremely fun to watch and identify in the field. Like most insects, their relatively small size and fast flight can make it difficult to tell one species from the next. However, there are a few rules of thumb that can help:

First, it is important to know whether you are looking at a dragonfly or a damselfly. Dragonflies tend to be larger and keep their wings out when at rest. Damselflies, on the other hand, are typically smaller, much more slender, have a bug-eyed look where their eyes stick out to the size of their heads, and often hold their wings along their bodies when at rest (unless they are spreadwings, which hold their wings in a posture in between dragonflies and most damsels).

Next, look for bold patterning on the wings and body of your insect. These markings can indicate what species you are looking at and whether it is a male or female. Size can also be a great clue for helping you determine exactly who you are looking at. 

This eight-spotted skimmer (Libellula forensis) has a distinctive wing pattern

Filigree skimmers (Pseudoleon superbus)  of Arizona and New Mexico also have distinctive wing patterns and interesting markings along the thorax.

One of the best ways to figure out which species you have encountered is to look at a field guide. We recommend these:

Dragonflies of California and the Greater Southwest by Kathy Biggs

Dragonflies and Damselflies of California by Tim Manolis

Dragonflies and Damselflies of the West by Dennis Paulson

There are also some great web resources for identifying these incredible creatures:

Kathy Biggs Website-  http://bigsnest.members.sonic.net/Pond/dragons/

Bug Guide- http://www.Bugguide.net

iNaturalist- http://www.inaturalist.org  

References:

Kathy Biggs, Common Dragonflies of the Southwest (Sebastapol: Azalea Creek Publishing 2004), 9.

University of California Museum of Paleontology website (http://www.ucmp.berkeley.edu/arthropoda/uniramia/odonatoida.html). Accessed 3, Sept 2014