Pollinator Study

Sunday, November 30, 2014

The Thanksgiving Salamander Hunt

    It is the day after our American Thanksgiving.  We are stuffed full of roast turkey and pumpkin pie.  We are sedentary, groaning from too much rich food and disinclined to leave the warm comfort of our couches,  but I have a longstanding tradition:  I make a point of getting out somewhere for a nature walk during this weekend, no matter how bad the weather.  So I grabbed a friend and we went on the great salamander hunt.

     We both have a burning ambition to see a mass amphibian migration.  In the Pacific Northwest the salamanders, newts and frogs march to the breeding ponds in spring and then march back into the upland woods to find a safe quiet place to hole up for the winter.  They often do these marches in large groups and we would love to see this.  Over the last couple of years, we seemed to have missed these moves:  they happen in unpredictable surges in the dead of a wet winter night so that’s not a surprise.  Part of catching these migrations in the act is to have a deeper understanding of the animals themselves.  So today’s field trip was in the nature of a scouting expedition to some possible breeding pond sites.  Long-toed salamanders, Northwestern Salamanders and Rough-skinned Newts were on our search menu, since they often time their return to the breeding ponds in early November into December.

Northwestern Salamander, sadly flattened
    Our first site showed no signs of amphibians and I was pretty disappointed. But then we moved on to another site in our region which is known to be a rich area for amphibians.  It is a county road that cuts through some high quality Douglas fir woods.  On one side are the woods, but on the other side are a series of shallow ponds.  The amphibians cross the road to get to the pond. On this road, there is little traffic and most make it across.  Though there are occasional fatalities:  here is the remains of a Northwestern Salamander, who met its doom under the tire of a car.  Far too many of our migrating amphibians are meeting this fate;  in Thurston county there is a real effort to identify the high-risk crossing areas and look at strategies for reducing this mortality. 

Rough skinned Newt in an alert, partially defensive posture
    As we drove along we saw more car-flattened remains.  Then suddenly I hollered STOP STOP STOP!!!!!  A salamander was lurching across the road.  When it saw us (or felt the vibration of the car) it stiffened its forearms and raised its head and tail in defensive posture.  That stance tipped me off to a salamander rather than a stick or leaf in the road.  This was a rough-skinned newt.  

     There was a mad scramble to park the car, grab cameras and boots and get to the critter before it made it across the road and into impenetrable shrubs.  Slipping and sliding on the wet grassy verge, we raced towards the newt. 

     The newt stayed where it was, still in defensive posture.  Rough skinned newts are poisonous to most other animals; only garter snakes seem to eat them with impunity.  Part of this defensive posture may be letting the bright orange underside be visible, which is a warning coloration to predators:  (if you eat me we’ll both be sorry).
   
Checking the newt for gender
     We gently moved the critter on to its back:  this was to check for gender.  In the breeding season the males have a swollen vent or anus at the base of the tail, just below the back legs.  The males also develop special dark friction pads on the bottoms of their feet, to allow for a better grip during a top-mounted copulation.  This animal has neither, so is probably a female.  Except it’s November and the breeding season has yet to begin.  So who knows?

     There are also adaptations it makes for living in the drier woods in winter versus the breeding ponds in spring.  In winter, its skin is tough, even warty and the tail is round.  For the breeding season it spends most of its life in water, so the skin loses its wartiness and the tail flattens out into a blade suitable for navigating in ponds.  This animal is still pretty warty on top so may just now be making its first move to the breeding pond. 

Rough skinned newt in pond
     We began prowling around the ponded waters on either side of the road.  Here we found a large rough skinned newt that had probably been living in water for a while:  its skin is fairly smooth on top and its tail forms a narrow blade for swimming.  In these ponds we found several more salamanders.

     We trotted up and down the road, from pond to pond, exploring all the salamander sign.  Though it is late November, cold and rainy and dark, there are still plenty of signs of life.   In the midst of winter, these animals are getting ready for the season to come.  It gives us great hope:  the wheel of the year is turning and sometime soon spring will be on its way. Yet another good reason for Thanksgiving…

Janet

Resources:
• Photos by Nancy Partlow, Glen Buschmann
   Some YouTube videos we made of this field trip:
•  Olympia Stream Team newsletter:  http://streamteam.info/pdf/current.pdf
    For local folks, Stream team will be offering a workshop on amphibians on Saturday Feb. 7, 2015
•  Amphibians of the Pacific NW by Lawrence Jones, William Leonard and Deanna Olson
•  Wikipedia - Rough-skinned Newt (Read the section Toxicity, which explains the RSN's neurotoxin and garter snakes' resistance to it.)


Freshwater amphibian pond near Olympia, WA

Tuesday, November 11, 2014

Predators and Prey

Bald Eagle adults in nest tree
      Today my sister Nancy, our dad and I took a walk around the middle part of the Deschutes estuary.  This is one of our favorite places and we visit it often in fall and winter.  The walk allows for a great view of a Bald Eagle nest on the eastern shores of the estuary.  Today we lucked out and saw the pair of eagles in their nest tree, perched high in a Douglas fir overlooking the estuary.  Their white heads gleamed like brand new tennis balls in the late afternoon sun.  Just underneath the tree, in the waters of the estuary, floated a variety of overwintering ducks.  I remarked that it was a great place for an avian predator to sit and survey the dinner table below, checking out which ducks would make a tasty midday snack.  This reminded Nancy of an experience she had had.  

     A few days ago she was also at the lake, taking a leisurely walk.  Suddenly she noticed a crow flying in big swooping loops, screeching at top voice, with a flight pattern which seemed to be directed at one spot on top of a nearby cedar tree.  She  immediately stopped her walk and started scoping out that tree:  as an experienced nature watcher, she knew the crow was zeroed in on something that Nancy had not yet seen.  The crow was absolutely right:  here’s what it showed Nancy:

    This is an adult Bald Eagle and most likely one of the mated pair that we saw in their nest today.  At this time of year the young eagle fledglings that were hatched last April are moving into independent life, so this adult is back to its usual winter schedule, perching near the lake edge,  looking for any late salmon in the fish runs up the Deschutes, or going after one of the wintering ducks on the waters of the impounded river. Or when that fails, waiting for one of the local Peregrine Falcons to make a duck kill, then forcing the hunter to dropping its catch.  (This is a mode of hunting called kleptoparasitism.)  

     This eagle is directing a fierce look at the crows who are harassing it. It is clear to me that the eagle would loooooove to get its talons on the taunting crow, but though the crow is smaller it is also far more maneuverable: it can easily evade any eagle attack.  It’s like a Volkswagen beetle dodging a Boeing 727 : this is no contest.  Now if the crow is sick, slow or stupid, all bets are off.  If I were the crow in question, I’d be pretty damn careful:  the look in that eagle’s eye gives me the willies.

     But the crow is not being foolish.  It knows that Bald Eagles eat crow babies and like all crows, it is born knowing how to make life uncomfortable for such predators.  So there is method in this crow’s madness.

      Over thirty years of birdwatching, I have seen similar examples of birds who respond to and give warning of the presence of predators.  One of my favorite examples comes from this same lake.

     I’ve been watching winter ducks at this place for many years.  It often happens that I’ll be watching a beautiful pastoral scene of quiet ducks, nibbling away at vegetation, dabbling for food.  Then all off a sudden every single duck on the lake rises up in screeching cackling cacophony, beating wings high and fast for distant parts, running for their lives.  When I see that behavior I start looking for the predator.  Today we saw exactly this at the Deschutes estuary:  we were
enjoying a beautiful view of the ducks on the water when all of a sudden they got really restless and took off in panicked flapping flight.  We all started looking for a predator and bingo!  both of the Bald Eagles were had left their nest tree and were flying over the lake to hunt that snack.  And the ducks knew it.

American Widgeons in flight
    One another occasion I was leading a field trip for a class of beginning birdwatchers.  We went to our friend Sherry’s house, where she had a fabulous feeding station set up on the edge of wetlands and woods.  We parked our butts on some lawn chairs and watched the activity:  we saw the usual winter guild of black-capped and chestnut-backed chickadees, red breasted nuthatches, songs sparrows, juncos and etc.  The chickadees were especially active, darting in and out of the tube feeder, grabbing a sunflower seed and taking it off to a private cache.  I was in teacher mode, identifying each bird and describing field marks.  Suddenly,  all the chickadees stopped what they were doing, rushed en masse into a nearby thick shrub and started making LOUD alarm calls.  This was clearly a teachable moment:  I told the students to start looking for some sort of predator, probably a sharp-shinned hawk.  And sure enough, lurking in the woods off to one side, we finally saw the sharp-shinned hawk.  But the chickadees had seen it long before we did and took steps to save their lives.

     Then there was the time I was out at Cape Lookout on the Oregon coast.  The Cape has tall cliffs in which gulls nest as a group during spring.  Bald Eagles are infamous for raiding these colonies and making off with shrieking gull chicks.  Not surprisingly, gulls hate eagles.  During one April visit to the Cape, I watched an immature Bald Eagle.  It had been perched low on the cliff and was attempting to take off in windy conditions.  As a novice bird it was struggling in the wind and some nearby gulls noticed this.  They grouped up and mobbed the eagle, striking repeatedly at it and doing their best to drive it into the sea, where it would most likely drown.  I watched for about ten minutes as  they very nearly pulled it off.  The young eagle came perilously close to the high surf crashing against the cliffs before it managed to pull itself up and away to safety.    
     We have no personal pictures of this but here is a link to a fabulous photo/story from Europe, where White tailed Eagles prey on Herring gull colonies:  http://io9.com/5856819/see-gull-take-on-eagle-in-mid-air-piggyback-attack

     There are all kinds of ways to be a birdwatcher.  One of my favorite ways is to watch behavior and in doing so, allow the animals to show you their lives and their concerns.  Today at the Deschutes estuary, we got an eyeful .

Janet

Resources:  all photos by Nancy Partlow