Wednesday, January 30, 2013

Fishing with Bread

When I was a kid, we use to traipse down to the Arkansas River with fishing rods and a box of Wheaties to mix up dough balls for catfish.  We watched others use bread dough balls with less success.  It is possible that there were heron watching and learning from us.

Mort Shurtz shared this video with me, demonstrating another technique of fishing with bread. This green heron is a patient fisherbird, giving a whole new meaning to "cast your bread upon the waters."  It is especially interesting how it retrieves the lure so it won't lose its bait.  We have all seen people feeding fish, ducks and geese with bread crumbs.  Apparently herons have noticed this as well.

video

This behavior has been reported before.  Green heron are only one of several bird species reported to "use tools."   A chestnut-backed chickadee has been observed using a stick or thorn to pry seeds from suet in a feeder.  The brown-headed nuthatch is known to use pieces of bark to pry off tree bark to reach insects underneath.*  While not exactly a tool, burrowing owls are known to bait an area with animal dung to attract dung beetles, a favored food item. **

While the green heron hasn't yet been observed with an open-faced spinning reel, this method is quite effective and this bird caught one more fish that I did my last time out.

More details on birds use of tools is at Stanford.edu.
*    nationalzoo.si.edu
**  Nature.com

Monday, January 28, 2013

Bees Switch Roles

Forager bee- Patrick Coin
One of the many puzzles about bees has been how a genetically identical hive of bees divides into separate, seemingly permanent castes.  A study from Arizona State University and reported in www.nature.com has given the answer.

Two of the subcastes are the nurse bees and the foragers.  The nurse bees are essential to maintaining the otherwise helpless queen and her larvae.  Foragers bring back nectar to feed the hive.  While their DNA was the same, there were differences in their DNA methylation. This suppresses the gene activation or its effect on the organism.  Essentially it turns down the volume of its signal.

As explained in Naturalhistorymag.com article, they then removed all the nurse bees from the hive.  When the foragers discovered the deserted queen and her larvae, some reverted to nurse bees and assumed their duties.  The researchers found that those newly converted nurse bees showed DNA methylation changes from their forager status to those typical of nurse bees.

To quote the www.nature.com abstract:
"In honeybee societies, distinct caste phenotypes are created from the same genotype, suggesting a role for epigenetics in deriving these behaviorally different phenotypes. We found no differences in DNA methylation between irreversible worker and queen castes, but substantial differences between nurses and forager subcastes. Reverting foragers back to nurses reestablished methylation levels for a majority of genes and provides, to the best of our knowledge, the first evidence in any organism of reversible epigenetic changes associated with behavior."
The whole field of epigenetics is a hot area of research, increasing our understanding of how DNA actually effects organisms.  While seemingly impossible to understand at first glance, there is a very lucid discussion which you can find at Naturalhistorymag.com.

Picture with the kind permission of Patrick Coin.

Thursday, January 24, 2013

Fight or Flight

This one is for fun- a biological hypothetical.  "Would you rather fight 100 duck-sized horses or one horse-sized duck?"  This question was put forward to President Obama in August on Reddit.com.  I am happy to announce that he stuck to the business of the country rather than taking a lot of time pondering it.  A story in The Atlantic assumed that task for him.

Einstein- Nationalturk.com
The article considers a lot of variables.  Einstein, pictured here, may be the world's smallest horse that isn't a dwarf; and he is cute.  So as President, would you rather be seen on the evening news stomping a hundred small cute horses or shooting a giant duck (in season of course- we are still naturalists).

Now which is the most dangerous?  Horses are herbivores and tend to run from danger.  Ducks can be pugnacious and loud, and they are omnivores so a small (to them) mammal might look delicious.

The there are the physical characteristics.  John Eadie, an expert on avian ecology at the University of California, Davis, lists eight characteristics that would make the horse-sized duck the more dangerous opponent.  Its powerful gizzard could crush you and your weapons.  Even the fact that ducks lack the intellect could make it easy to outsmart them.
"Ducks are dumb. There is a record of some research in which half of a duck's brain was removed surgically ... with no discernible change in its behavior," Eadie explained, though he didn't see that aspect of its biology as an unalloyed advantage. "The flip side, is that in battle, I could literally destroy half the terror-duck's brain and it would have no impact on the battle. Nothing worse than a dumb opponent who doesn't know how to quit."
Flying steamer duck- Wikimedia
But just how aggressive can a duck be?  You might be surprised if you ran up against a Flying Steamer Duck, Tachyeres patachonicus .  An article at scienceblogs.com describes this impressive aggressor which lives in the Falklands and Patagonia.
"Steamer-ducks are notoriously pugnacious. Heavy-bodied and robust compared to other ducks, they have tough skin, a massive head and neck, and are equipped with keratinized orange knobs on the proximal parts of their carpometacarpi. Both sexes use these wing knobs in territorial fights and displays. Fighting males grab each other by the head or neck and then whack each other vigorously with the wing knobs, and fights can last for up to 20 minutes. Both birds sometimes submerge during the fight, and come up still fighting.
An aggressive steamer-duck approaches an ‘enemy’ by either adopting the so-called submerged sneak posture (only the top of the head and back and tail tip are visible), or by ‘steaming’ noisily across the surface (the ducks charge at speed, throwing their wings like the paddles of a paddle-steamer, hence the vernacular name)."
They will actually attack and kill other duck species.  Why they do this isn't clear but this violent attack apparently excites the female Steamer, possibly bringing her to a full boil.  And why are they called the "Flying" Steamer Duck?  Because they are the only variety of steamer duck which can fly.  But even here there are exceptions.
"What makes the species especially interesting is that some males within the species actually have wing loadings that are too high to permit flight, and are thus flightless. So, within a single species, there are both flighted and flightless individuals. It is almost as if the species is poised in the transition to full flightlessness."
All of this is good news for the White House.  It is 6,344 miles from Washington D.C. as the crow flies, and these steamer ducks aren't crows and it is longer around the curve of Brazil.  It is unlikely that President Obama will make the trip to Stanley, Falkland Islands so he is probably safe.  On the other hand, if I were Great Britain's Prime Minister, David Cameron, I would be a little concerned, and might take up duck hunting in preparation for the next Falkland crisis.

Special thanks to Dr. Chris Barnhart for pointing me to the story.

Monday, January 21, 2013

Leopold Plants Bloom Earlier

Serviceberry Missouriplants.com
There is an interesting research study published in Plosone.org which could well have listed Aldo Leopold as a co-author.  The fact that plants are flowering earlier than in the past has been documented by many different studies, but this paper shows that the conclusions for experimental data from controlled studies were too conservative in predicting flowering times.

Phenology is the study of the effect of climate, including seasonal and annual variations, as well as  elevation on plant and animal life.  This has become all the more important as we face the dramatic climate change of the last decade.  The researchers studied bloom times in the same areas as classic studies that were carried out years ago.
To quote:

"From 1852–1858, Henry David Thoreau, author of Walden, observed flowering times in Concord, Massachusetts, USA. And from 1935–1945, Aldo Leopold, author of A Sand County Almanac, recorded flowering times in Dane County, Wisconsin."
"Several recent re-surveys at these locations, nearly 1500 km apart, indicate that many spring-flowering plants now flower much earlier than in the past. This trend appears to be attributable to especially warmer spring (March, April, May) temperatures. In 2010 and 2012 in Massachusetts, and 2012 in Wisconsin, spring temperatures were the warmest on record."
By comparing these careful daily observations of bloom times from 65 and 156 years ago, the authors have been able to document real long term changes in bloom times.  For example, studies on the same parcel of land shows high bush blueberries blooming 6 weeks earlier than they did in the 1850s.

A study done on Leopold's land recently showed a changes in bloom time.  While Leopold recorded the flowering of serviceberry (Amelanchier arborea),  between 10 April and 9 May, this study found it flowering on 25 March, 2012.  Barb's diary shows it blooming in Bull Creek valley 16 March, 2012, ten days after the Bradford pear along the roads.
"These long-term datasets thus provide a rare opportunity to investigate if historical relationships between flowering times and spring temperatures apply during these record-breaking years." 
While their going out daily to record the time that plants first bloomed over a number of years might seem strange or even outright weird to many today (though certainly not Barb) our present day botanists are grateful for their help.

Thursday, January 17, 2013

Traffic Noise

We recently posted on grasshopper mating including studies of a species which produces louder calls when living along busy highways, attracting mates over the competing sounds of traffic.  Our Master Naturalist Bob Korpella posted a similar story about birds on Freshare.net. To quote his source from the Max Planck Institute:
"To attract mating partners and defend their territories, urban robins sing later in the night, once traffic noises decrease after the evening rush. Many other bird species, including blackbirds, sing in urban environments at a higher pitch, so that their song is easier to distinguish in the lower-frequency traffic noise."
National Geographic
Like young people at a loud party, communication has to get above the ambient noise.  For the most part, birds are faced with a more constant sound, unlike the constantly changing background of a DJ's selections.  And like humans dancing, they learn their own moves to attract a female's attention.  The highest points for style go the the Bird of Paradise as seen in this video.

Probably the most athletic is the Golden-collared Manakin.  As you can see in this video, he leaps between parallel branches, using his wings only to soften the landing, and even throwing in a back flip from time to time.  During these athletic moves, its heart rate jumps from its normal 600 beats per minute to an astounding 1300 beats per minute (21 beats a second)!
“The females pre­fer the males that pe­r­form the el­e­ments of the dance faster and dem­on­strate bet­ter mo­tor co­ordina­t­ion,” said lead au­thor Jul­ia Bar­ske, a grad­u­ate stu­dent and doc­tor­al can­di­date at the un­ivers­ity. “Females pre­fer more ac­tive males that do more court­ship ac­ti­vity.”

“Jul­ia’s da­ta show that the females se­lect the males that com­plet­ed el­e­ments of the court­ship dance in 50 mil­lisec­onds (thou­sandths of a sec­ond) over the males that took 80 mil­lisec­onds,” Schlin­ger added. "  World-Science.net
Different species have different styles and hopefully always will.  The thought of a collection of different bird species dancing Gangnam Style in our yard is too horrible to contemplate.

Monday, January 14, 2013

Grasshopper Mating


Grasshoppers are sexy- take it from our Master Naturalist Towanda Warriors.  During a recent outing along Bull Creek they hiked, practiced yoga (I can't send those over the Web) and observed nature.  

A highlight was watching a pair of grasshopper who patiently ignored us for 10 minutes while they went about their business.  It appears that November was mating season.  I was curious about their species but didn't have the heart to interrupt them to check their wing pattern.  They finally jumped away, flying awkwardly to a more private rendezvous.



Click to Enlarge
Males attract mates in the fall mating season with some combination of calls, appearance, pheromones, and in some species by drumming and posturing.  Their calls, called stridulation, are created by rubbing the rasp-like lower back legs against the forewings.  Mating itself may last from 45 minutes to all day.  Some species mate with multiple males, the newest males sperm replacing the the prior male's donation.

A recent study reported by Time demonstrated that some grasshoppers have learned to adapt to human noise.  They demonstrated that "male bow-winged grasshoppers, Chorthippus biguttulus, who live near highways adapt their mating calls to make them audible to females over expressway noise."   They placed 188 separate grasshoppers in a box facing a female and recoredd their calls.  Those collected by highways produced a higher-pitched call to rise above highway noise.  This study was done in Germany and it hasn't been repeated yet along I-44.

Click to enlarge
National Geographic discussed the nutritional value of grasshoppers and other insects.  Did you know that a 100 grams of grasshoppers contains 20 grams of protein and 153 calories?  Did you care?  I think that they would be an excellent diet food as you would burn at least 1000 calories catching that many grass hoppers.

Friday, January 11, 2013

Beaver Facts

Our latest beaver adventures in beaver trapping led me to review their chapter in Mammals of Missouri by Charles and Elizabeth Schwartz.  This is a tremendous resource, compiling more mammal details than any other single source.  The Missouri Department of Conservation web site has good general information but doesn't have space for all the little incidentals that Schwartz lists.

Underfur, guard hairs and front claws
The beaver hide is covered with dense soft underfur for warmth.  Reddish to black longer guard hair on the outside protects the underfur from environmental factors and trauma, keeping the animal fluffed, dry and warm.  Slipping my fingers into the underfur, it felt soft and almost dry, providing excellent insulation.  The front feet are equipped with long claws, allowing it to dig its den into the creek bank. The beavers' large hind feet are specialized for swimming with webbed toes.  The webs also help it walk across soft muddy ground.  

Webbed hind foot
Click to enlarge












Beaver have especially large lungs which hold a supply of air as well as an enlarged liver which stores enough oxygenated blood to permit beavers to stay underwater for 15 minutes at a time.  They can thus swim long distances under water and into safety, avoiding predators.

Double-edged secondary claw
The hind toes of a beaver have special grooming adaptations.  The three outer toes of the hind feet have typical claws, but the two inner toes possess specialized claws that are used to comb the fur, remove parasites, and distribute oil. "The innermost toe has a long, double-edged claw that clamps down over a long, soft lobe, forming a 'coarse comb'; The second toe has a similar claw but possesses a horny growth with a sharp finely cut upper edge between the claw and the soft lobe below, forming a "fine comb."*

Beaver in southern Missouri seldom construct lodges and tend to live in bank burrows.  The fast flowing, flood prone streams tend to wash out the dams frequently, making the mounded homes they build up north more temporary.  Here we identify their location by food piles of sticks stored under water as well as their slides and harvested stumps.  Their burrows along Bull Creek are frequently limited by the rocky shelf under the soil.  They will raise the roof close to the top soil, causing a collapse.  This may cause them to create a new burrow as well as promoting further bank erosion with the next flood.

In the 1860s there were still lots of beaver in all the Missouri watersheds in spite of commercial trapping.  By 1895 there were only a few left due to landscape changes and uncontrolled trapping with improved techniques.  From 1928 to 1955 there was a restocking program, importing beaver from other states.  As far as Bull Creek is concerned, this has been a tail-whopping success! 


* Quotes from The Wild Mammals of Missouri by Charles and Elizabeth Schwartz, University of Missouri Press. 2001.

Wednesday, January 9, 2013

Beaver Timber Stand Improvement


Our recent Battle with Beavers left me with a question.  Why do beavers cut down trees far bigger than they can use?  They had girdled over 15 trees in the 8-14 inch range on a small patch of creek side bank between Bull Creek and an adjacent oxbow pond.  Animals adapt to their territory and rarely spend energy on activities that aren't necessary for survival such as eating, procreating and escaping danger.  This was far more that they could ever eat and yet they used a lot of energy in the effort.


Willow cuttings
Beavers eat mostly soft herbaceous plants in the summer and woody species in the winter.  In general, they prefer eating the soft xylem wood under the bark of young trees and limbs, especially willow.  Unfortunately in the area where we had to trap beaver recently there are nice high banks for dens but few young tender trees.  They therefore have been girdling and felling mature ash trees of 6 to 14 inch diameters.  I couldn't understand why they would invest that much time an effort on big mature trees until I read about coppicing, the practice of cutting a tree to produce basilar shoots.
Greeneway Tree Care

In the middle ages, coppicing was a common method of managing a forest.  It was a lot of work to cut a large tree with the crude axes of the timeSince the King and his nobility owned the forests and controlled wood harvesting, the peasants weren't allowed to cut any trees.  They were allowed to harvest any dead sticks for firewood, including dead branches they could break off a standing tree.  They used a hooked tool for this, felt to be the origin of the saying "by hook or by crook."

The king and nobles owning the forest could control the frequency of cutting trees and the number of mature trees left for future construction of buildings. By cutting a tree and using the lumber for construction, they would also produce a future dozen smaller shoots around the base of the stump to harvest in a few years.  This could be more easily cut for fire wood.  
"The shoots (or suckers) may be used either in their young state for interweaving in wattle fencing (as is the practice with coppiced willows and hazel) or the new shoots may be allowed to grow into large poles, as was often the custom with trees such as oaks or ashes. This creates long, straight poles which do not have the bends and forks of naturally grown trees.  Coppiced hardwoods were used extensively in carriage and shipbuilding, and they are still sometimes grown for making wooden buildings and furniture."  Wikipedia
Beaver Coppice- Click to enlarge
When a tree is girdled by a beaver, the stump usually will produce a dozen or so shoots around the base.  Left alone, these will grow into nice bite size small trunks, just perfect for beaver food.  They get some of the branches from the felled tree and produce a food factory for coming years, their own quick shop.  How they discovered this old forestry technique is unknown, but I suspect that they learned it before we did.

 Unfortunately they tend to girdle more trees than they fell, not necessarily saving some for the future.  Our beavers did something even more puzzling.  They chewed one large trunk into a "string of pearls" configuration.  The area they had settled in has only mature trees instead of their preferred willow.  I have to think that they weren't finding enough young branches and were eating into the more dense heart wood.  Or maybe they just wanted more fiber in their diet to improve their colon function.
Little innocent beaver with beaver log

Monday, January 7, 2013

Hawk Moth

I received this picture from fellow Master Naturalist, Michael Baird with a note:
"Here is the Pink-Spotted Hawk Moth, Agrius cingulatus (Fabricius), I found outside of Maschinos, laying in the alley. After doing a little research I found that they are common to Missouri in the fall, occasionally breeding in southern counties.  The adults visit flowers, usually the deep-throated species."
Butterflies and Moths of Missouri* has this to say about A. cingulatus: "In Missouri, there are records from June to mid-November."

by Paul Ingram on silkmoths.bizland.com
As Michael notes, "Adults nectar from deep-throated flowers including moonflower (Calonyction aculeatum), morning glory (Convolvulus), honey suckle (Lonicera) and petunia (Petunia species)."**  It feeds by hovering like a hummingbird while unrolling its incredibly long proboscis into the deep well of nectar.

The Agrius cingulatus (a.k.a. Sweet Potato Hornworm) larva is shaped like a typical hornworm (think Tomato Hornworm) but with different coloration and vertical stripes on its head.  Like other hornworm caterpillars, it shares a digestive affinity for the same vegetable plants that we do, in this case eating the leaves of a tuber, the sweet potato.  Some would call this a pest, others a beauty.

Originally it was a neotropical species with a range from South America and Mexico with some migrating as far north as Canada.  Since then A. cingulatus has really taken advantage of the Columbian Exchange and become a world traveler as in this early report:  "Specimens have been found in England (Barrett, 1895) and on ships off the French coast."  Now it really gets around.

"Extra-limital range: The tropics and subtropics of the New World, and the Galapagos and Hawaiian Islands. As a migrant, Agrius cingulata flies north to Canada, south to Patagonia and the Falkland Islands and, occasionally, to western Europe. A. cingulata has recently established itself in the Cape Verde Islands west of Senegal, West Africa (Bauer & Traub, 1980), adults having arrived, presumably, from Brazil." silkmoths.bizland.com

So what is the secret of its successful travel around the world?  I speculate that like Popeye, it is in what A. cingulatus larvae eat.  The favorite food of its larvae is the sweet potato, Ipomoea batatas.  Unlike Popeye, who said "I yam what I yam and that's all that I yam," the sweet potato is not a true yam but a member of the morning glory family, producing the same deep flowers that the moth likes to nectar upon.

Originating in the Western Hemisphere, the sweet potato has been spread around the world by man.  It is propagated by vine cuttings and not by seeds.  It first traveled to central Polynesia around 700 AD, possibly transported by Polynesians who some feel reached South America around that time.***  Following the Columbian Exchange created by early European exploration of South America, it traveled to Africa where the sweet potato became a popular staple.  Transported by cuttings, I would speculate that the A. cingulatus larvae  and eggs also made the trip on the vines necessary to survive the long ocean voyage.


*       Butterflies and Moths of MissouriJ. Richard and Joan E. Heitzman.
**     This quote and a picture of its incredible proboscis is from silkmoths.bizland.com
***   For more on this see wikipedia.org Sweet_potato 

Saturday, January 5, 2013

Beaver Battle


Beaver willow harvest
It has been a good beaver year on Bull Creek... or a bad one depending on whether you are a beaver or the land owner.  Every year at this time the beaver dams appear and the willows along the downstream banks start to disappear, only to reappear as pealed sticks in the creek.  It is always a treat to check out as we cruise the creek. 

Beaver love the willows whose bark is a primary food source. They can mow the gravel bar nearly clean and yet the next year it will be a dense thicket with thicker trunks.  With a renewable resource like this, we should be theoretically able to enjoy beaver entertainment forever.

Threatened riparian bank
We have never gone a year without beaver living along our banks.  Unfortunately, every few years the parents will make their way upstream and then the problems begin.  Suddenly there are new mature bankside trees girdled daily.  With time, some are felled while the rest are sentenced to death by lack of circulation.  Trapping a few will give the problem areas some time to regenerate but a few years later the numbers increase and the tree slaughter begins again.

This year the damage was particularly dramatic, killing over 50% of the trees along the oxbow pond.  Pencil point stumps both fresh and old dot the area, a few surrounded with a dozen suckers sprouting into a replacement. While we are invested in expanding the riparian plantings, they follow their dietary urges, decimating the existing mature corridor.  Man is now their only significant predator.
"In some situations, these animals can enhance the value of wetlands for other wildlife. Yet, populations of beavers must be closely monitored and occasionally controlled to avoid problems associated with their over-abundance." MDC

Trapping is now a part of the balance of nature in Missouri and it is now trapping season* through March 31.  I quit trapping some years ago.  Wading in waist deep water, and reaching down into the freezing water to set the traps is a younger man's sport.  Traps must be checked every 48 hours.  Cleaning and stretching the pelt on a willow frame took hours and ended any "mountain man" fantasies quickly. 

50# plus beaver
We had friends come in to trap again this year.  They caught two big fat beavers on this stretch of creek, each weighing 50 pounds or more.  We assume that these are the parents of the offspring living downstream.  One way to know that the beaver are all gone from the area is to break a hole in their dam.  They will generally repair a hole overnight.  The dam is now remaining open and hopefully the remaining trees are safe for now.

Disrupted beaver dam
Some years ago when I was trapping beaver, I worked over an hour to create a hole in a two foot high dam across a wide stretch of Bull Creek.  I set a trap six feet up stream above the hole, anchored with large cedar poles creating a channel they would have to enter to do their repair work.  The next morning I found the dam repaired with my trap and the poles deeply imbedded in its structure.

It should be several years before the beaver population reaches a level where they are destroying the large trees.  As long as they are feasting on our tasty willows, we will remain good neighbors.

* Off-season trapping is only done by the Missouri Department of Conservation when beavers are causing significant financial damage.  This includes destroying urban plantings and obstruction of waterways of importance.