Wednesday, February 10, 2016

Carnivore Attacks

Noppadol Paothong - MDC
A recent study of carnivore attacks on humans is worth reading.  It focuses on attacks by brown and black bears, coyotes and cougars. which are increasing in frequency.  While the 24 hour reporting cycle of media with sensational video reports catches our attention, the attacks are infrequent and frequently preventable.

The species most likely to attract out attention in Missouri is the black bear which is actually an omnivore, carnivorous primarily when the exceptional opportunity presents itself.  Steven Herrero of the University of Calgary is an authority on bear attacks and safety, and he reviews the study's results at this link.*

As the human population climbs, we move further into landscapes previously the domain of coyotes, bears, wolves and cougars.  More outdoor activity in the wild and an emphasis on extreme adventure puts people at greater risk.  On the other hand attacks remain rare, especially when we consider the increasing numbers of humans out in the wild.  They found 700 attacks from all species in North America and Europe since the 1950s.  Their results are summarized below.

As more people enter the wilderness areas, there is an increasing need to educate the public on managing their risks.  Around half of well documented incidents were associated by risky human behavior, especially leaving children unattended, running and hiking alone at dusk.  Other factors included walking with a dog and dealing with a wounded animal while hunting.  Feeding bears and sleeping in tents with food supplies further encourages attacks. 
Click to enlarge - from Nature.com
It is important to understand relative risks of outdoor activities.  Statistics for the United States from Outdoor Life  list mortality from outdoor activities.  There are annually an average of 5 fatalities from venomous snake bites and 51 deaths from lightening.  This compares with 55 deaths from black bear attacks over the last 110 years.  Some Missouri figures are below.


Missouri Outdoor Mortality - MDC
    Take home lessons:
    1. Attacks by bears and carnivores are extremely rare.
    2. Avoid feeding bears.
    3. Become Bear Aware.

    * The complete study with the data is at Nature.com.

    Monday, February 8, 2016

    He or She or It

    Timothy Knepp - US Fish and Wildlife Service
    Sex change is in the news a lot and now the fish are joining in.  National Geographic describes the findings in Vermont's Missisquoi National Wildlife Refuge.
    "About 85 percent of male smallmouth bass collected in national wildlife refuges in the Northeastern U.S. had eggs growing in their testes. Pollutants that mimic sex hormones are the suspected culprit."
    Eggs?  Well shut my mouth! - Bill Roston
    Scientists studying fish in 19 national wildlife refuges in the U.S. Northeast have found that 60 to 100 percent of male smallmouth bass had testes growing female egg cells.  This condition called intersex is not new but the increasing frequency is alarming.  It had previously been described in a Science Friday story back in 2006 and examples were known from the 1990s.

    The suspected culprits are endocrine disrupting chemicals (EDC) entering the watersheds.  These can be found in pesticides, electronics, personal care products and cosmetics.  Chemical contaminants of concern include estrogens from birth control pills, the plasticizer bisphenol A, and the herbicide atrazine.  Laboratory studies of the diabetes drug metformin, using levels found in Lake Michigan water, has been shown to produce intersex fish.

    Intersex changes have previously been documented in alligators, soft-shelled turtles and frogs.  Studies in Europe have shown that fish with eggs in their testicles tend to produce less sperm which have reduced motility, leading to reduced reproductive rates.

    We have no studies from our Ozark streams where our smallies reside.  Studies in Northeastern US waters have shown a much lower incidence of intersex fish among largemouth bass populations, a hopeful note for fishing on the White River lakes.  One more reason to keep our waters clean.

    Keep up on the latest on the Upper White River status with Ozarks Water Watch.

    Wednesday, February 3, 2016

    Sundew Assassin Bug

    Assassin bug nymph - Mark Bower
    While photographing lichen on Monday, Mark Bower came across this insect trying to look inconspicuous on a lichen covered stick.  It had the typical morphology of an assassin bug nymph, but which one?  I sent it to Bugguide and got my answer within 30 minutes - the Sundew Assassin Bug,  Zelus luridus.

    Prominent spines on pronotum - Mike Quinn
    Z. luridus adults are basically green with a few color variations  (luridus = sallow, ghastly).  The nymphs can vary from bright orange to blended mixtures of green.  According to Bugguide "The best feature for recognition is the pair of delicate spines on the rear corners of the pronotum, which are rather long on the light colored individuals and shorter on the dark."
    Z. luridis nymph - Mark Bower

    Both adults and nymphs prey on a wide variety of insects such as weevils and leafhoppers but much of their diet is lepidoptera larvae including butterfly caterpillars and many economic pests such as cotton bollworm.   They can be considered "good" or "bad" from our perspective but as usual, it depends, and they don't seem to care what we think.

    Adult luncheon date
    A quick trip to a favorite insect site called Bugeric.blogspot.com* brought up lots of good stuff.  Z. luridus has a cool predation strategy, or should I say sweet one.  They secrete sticky substances from glands on the tibia of their front legs.  This covers the hairs allowing them to capture their prey rather than relying on stabbing them like most other assassin bug species.  After that it is the same old story - inject digestive juice, wait and then suck out the digested contents.  Not exactly gourmet dining but it works for them.

    A leafhoppers nightmare, Z. luridis egg mass and hatchlings - bugeric.blogspot.com
    The nymphs pass through 5 instars (stages) on the way to adulthood.  While they may commonly overwinter as eggs, Mark's didn't get the message and was moving about on a cold winter day.  Bugeric points out that the nymphs don't produce the sticky secretion but instead wipe them up from secretions that their mom left on the egg sac.  Details like this always make me wonder who bothered testing these tiny nymphs and how.  Here you can read the answer - C. Weirauch- 2006 described assassin bug methods of prey capture in detail.  Studies like this add up to the complete descriptions in field guides.


    * Bugeric's blog is a great place to check for insect lore.  He is the author of my favorite insect field guide, Kaufman's Field Guide to Insects of North America.

    Heavenly Bamboo

    N. domestica leaves- Wikimedia
    Invasive plants from "heaven" now comes in two plant species.  The more familiar species is Ailanthus altissima or "Tree of Heaven," a small tree that spreads like kudzu of the north and even grows in the cracks of buildings.  Now we have another species popping up around Springfield, Heavenly Bamboo, Nandina domestica.  It came down to us not from heaven but from Asia.

    Heavenly Bamboo berries - Wikimedia
    Not actually a bamboo but an evergreen shrub, it tends to grow around 7 feet tall and spread out to 5 feet wide.  Introduced as an ornamental in the 1800s, it can seduce gardeners with its young pink leaves in early spring, white flowers in early summer and bright red berries in the fall and winter.  Oh, and evergreen leaves that may be tinged with red in winter..... beginning to sound like invasive bush honeysuckle?  It should, as it spreads covering the same habitat.

    There are clues to look for when planting exotic (think non-native) plants.  "Needs no care," "grows in sun and shade,"  "grows in any soil," should all be a warning that escape is likely.  "Heavenly" grows readily up to 6-8 feet although there is a dwarf variety of 3-4 feet.  It spreads out by rhizomes, seeking to grow beyond the gardener's plan, and can cover the ground quickly like bush honeysuckle.  Nandina can take heat and cold, from −10 to 110 °F.  It grows in sun or under forest canopies and near forest edges like bush honeysuckle and Arkansas is an epicenter for Nandina in forests.

    All parts of the plant are poisonous, producing hydrogen cyanide.  They are listed as Toxicity Category 4, the category "generally considered non-toxic to humans," but the berries are considered toxic to cats and grazing animals.  They generally do not affect birds except when consumed in large numbers by voracious frugavores like cedar waxwings.  I recall sampling honeysuckle berries and neighborhood kids mashing them for "tea."  These berries potentially could sicken small children who sample them in excess.

    Leaves - Invasive.org
    They were planted in the Master Gardener's Xeriscape Garden on National Avenue in Springfield.  And a confession, we have had some planted in our yard for 20 years, although Barb suspected they might be a problem and has picked the berries off each year before they ripen.  For some time they have been classed as invasive in the southern states including  Florida, Georgia and Texas.  Now it looks like Missouri's turn has come.

    Fayetteville has just banned planting 18 invasive species in major developments as described here.
    Detailed information of Heavenly Bamboo control is at this Forest Service link.

    Monday, February 1, 2016

    Birdwatchers Unite!

    Bird migration routes by eBird- New York Times
    Studies of bird migration have always been complex and expensive, using an array of techniques such as traditional VHF, digital coded VHF, GPS transmitters, Argos satellite transmitters, geolocators, and GSM transmitters.  While giving good information these require capturing a bird and attaching a device.  The bird has to haul around the extra weight and when you are done, you have a path for one bird only.

    The first migration study was by marking swans with a nick in their beak in 1560 England.  Other methods listed in Wikipedia (scroll down to "study techniques") have included "an older technique to quantify migration involves observing the face of the moon towards full moon and counting the silhouettes of flocks of birds as they fly at night."

    A story in the New York Times describes an exciting new approach involving citizen science.  Ornithologists at Cornell Lab of Ornithology have compiled more than a million observations reported by amateur bird watchers through eBird.  Many of our own Master Naturalists have participated through GOAS* field trips and as observant birders.

    Nocturnal migration is difficult to study as the birds tend to take off 30-45 minutes after sunset.  Cornell's Birdcast program is combining eBird data with two other high-tech data sources.  Flight calls of migrating birds are species specific, allowing species identification during nocturnal flights.

    Weather Surveillance Radar (WSR-88D) network has over 140 sites dedicated to collecting meteorological phenomena.  These can also track the movement of masses of birds at night, "determining where flights are occurring, how many birds are aloft, and in what direction and speed they are moving." (BirdcastWhile not species specific, this can be correlated to flight calls and eBird data to describe species-specific bird migration routes.

    Even if you don't read the article, this link is worth a click just to see the flow of  migrating species shown as moving dots over the year.

      * GOAS - Greater Ozarks Audubon Society.

     This story was contributed by my fantastic editor and wonderful wife.

    Saturday, January 30, 2016

    The Price of Extinction

    Lord Howe's Stick Insect - "World's Rarest Insect"- Australiangeographic.com
    Lonesome George - Wikimedia
    There is a price we pay for extinction as well as the cost of preventing it.  Condors, whooping cranes, even pandas can be considered charismatic species we struggle to preserve.  For Lonesome George in the Galapagos it was too late as he lived for years with no remaining female to mate with.



    All this leads up to a fascinating update to a story by Robert Krulwich about the Lord Howe stick insect, Dryococelus australis, that was found barely hanging on, literally, to an isolated 1700 foot volcanic remnant named Ball's Pyramid.  This is in the South Pacific 13 miles from Lord Howe's Island, the insect's original home where it had gone extinct 80 years before.  The followup ends with a video of its amazing emergence from a tiny egg, much like clowns emerging from a circus VW.

    In Missouri, a less charismatic American Burying Beetle comes to mind as an example of the public's efforts to restore an endangered species.  Although far from being cuddly, its habits are fascinating and the restoration efforts include the St. Louis Zoo and volunteers from around the state.

    While I personally think that attempts to "restore" the Wooly Mammoth
    is more a gee whiz exercise in DNA sequencing and genome editing rather than a pure species restoration, I think it is worthwhile to try preventing extinction of those species around us. I would hate to lose the Missouri Bladderpod or the American Burying Beetle on our watch.

    In a somewhat related story, a recent study has demonstrated that early Australian settlers around 50,000 years ago caused or contributed to the extinction of the 500 pound, 7 foot tall flightless bird, Genyornis newtoni.

    Monday, January 25, 2016

    Shocking Bear Video

    Grizzly bear facing a shocking carcass - Montana Grizzly Research
    Bears are among the most intelligent mammals.  Some have suggested they are as intelligent as a 3 year old child.  It is at that point that we have to separate intelligence from trained performance.  Obviously a child can perform far more tasks as they grow and are trained.

    Sophisticated studies have shown some limited numerical abilities of bears.  This was demonstrated by captive bears using touch screens with their noses.  They could be trained to make a selection based on the limited number of dots on the screen.  (If the bear used its paw the researchers would have gone through a lot of touch screens). 

    Does this translate to bears in the wild?  Children don't start out life with counting and language skills.  Teaching a child requires their concentration and avoiding distractions.  Likewise the bear needs to focus.
    "What's most interesting is that this level of intelligence and cognitive reasoning is not often observed among bears in the wild. A possible explanation for this is that a bear in the wild is so driven by the single-minded purpose of survival and finding enough food before the onset of winter that the full scope of what they're capable of must often take a backseat to wild instinct. Researchers like Else Poulsen and Doug Seus have shown that when a bear is kept in captivity, well-fed, cared for, and given a stress-free life, the other side of their nature becomes more apparent and takes precedence over instinct."  Where the Bear Walks
    It is frequently hard to separate intelligent behavior from random chance as described in this blog.  Dave Shanholzer sent me this video of a grizzly bear faced with a carcass wired to shock it.  The bear's response looks to be the result of tenacity and an accidental solution.  It would be interesting to see what its response would be if tested with several more carcasses.  Would it "know" to disconnect the battery first?  Who knows?