Partial Migrants: Should I Stay or Should I Go?

By Sonia DeYoung

Outside my window, a robin pecks around in the rain. It’s the day before Thanksgiving, and the forecast calls for the rain to turn to snow tonight in my Massachusetts hometown. So why isn’t this robin right now flying south toward a warm, easy winter?

American robins are facultative partial migrants:  they decide each year whether to migrate

American robins are facultative partial migrants: they decide each year whether to migrate

Casual birdwatchers see robins as harbingers of spring, but you can actually find them year-round throughout much of the U.S. Based on my own observations, robins seem to stick around more now than they did twenty years ago—perhaps global warming plays a role in that trend (see November 6 post). But climate change can’t explain why some robins flee wintertime and others take their chances.

[Update: The day after publishing this post, I stumbled across an article by biologist Mark Davis saying that more robins stay in the north for the winter now because of a greater winter food supply: they happily eat the berries of several increasingly common non-native species.]

Many birds, like warblers and hummingbirds, migrate annually no matter what. Others, including robins, kingfishers, and chickadees, are “partial migrants”: within a single population in a given year, some will migrate and some will not. Backyard birdwatchers who rejoice in the first robin of spring aren’t necessarily unobservant. There are fewer robins around in winter, and those that do stay often roost in bogs and swamps instead of backyards. Each year, a robin must decide based on the available food supply whether to migrate; a snowy winter landscape can never provide as much food as the same land in summer. Some robins may even leave mid-season if the conditions turns especially harsh.

They’re taking a gamble either way. Birds who reside year-round in temperate climates risk a 50-80% chance of death each winter. Migrants do a little better, with at most a 50% chance of death. But they invest a great deal of time and energy in migration that they could have put toward reproduction. Temperate residents make up for their high winter death toll with their better success raising offspring.

European robins are obligate partial migrants: genes determine which members of a population will migrate

European robins are obligate partial migrants: genes determine which members of a population will migrate

Not all partial migrants have to make this annual choice. Within a single population of European robins (not closely related to American robins), genes dictate which individuals will migrate and which will stay. With these birds, migrants are born, not made. Gene-determined migrants like European robins are called obligate partial migrants, while American robins are examples of facultative partial migrants.

Still other kinds of migrants do make a choice, but it’s a group decision. Evening grosbeaks and snowy owls, for instance, will leave their typical wintering grounds en masse if the autumn produced a poor seed crop. Then they pop up in unexpected places in what’s called an irruption: an unpredictable winter boom of birds.

The robin outside my window, though, didn’t have the advantage of consensus to decide where to spend this winter. She reminds me that animals are individuals who must make daily life decisions based on their experiences. Watching her hunched under the cover of a dripping rhododendron, I hope she made the right one.

Information gathered from The Handbook to Bird Biology published by the Cornell Lab of Ornithology; Living on the Wind: Across the Hemisphere with Migratory Birds by Scott Weidensaul; and the Audubon Society and Smithsonian field guides to North American birds.

 

Give it a Shot: Staying Safe in the Woods During Rifle Season

Shelby and one of her dad's bucks sometime in the early 90's.

Shelby and one of her dad’s bucks sometime in the early 90′s.

It’s hunting season, and this year I’m working through my end-of-semester stress with a rifle.  I’ve never been a hunter before, but, as a native Vermonter, deer camp, hunter-safety orange, and the first rule of gun safety (always point your muzzle in a safe direction!) have been in my vocabulary since childhood.  As I prepare for my first rifle season as a hunter, I have been surprised to find that many of my classmates did not grow up around hunting, and haven’t really thought about what it might mean to them.  Staying safe during hunting season really boils down to three main points, and shouldn’t be intimidating or frightening.

  1. Be visible.  Wearing hunter-safety orange any and every time you go out in the woods during rifle season is a must.  A lot of people think wearing any bright color will do, but almost nothing is more visible and recognizable as human in the late fall forest than hunter-safety orange.
  2. Be respectful.  Few things are more frustrating for a hunter who has been shivering silently in a tree stand since dawn than a person or dog thrashing obliviously past.  If you think there might be a hunter already in the woods it’s best to stick to heavily traveled trails or to just avoid the area during rifle season altogether.  Less about safety and more about etiquette, respecting other legal uses of the forests you love is a condition on which your own access depends.
  3. Take it seriously.  “It won’t happen to me” is the wrong approach to safety during hunting season.  Spend 8 hours looking for deer in the woods and your brain will start to make them out of everything – tree branches are antlers, the crunching leaves under a retreating rabbit are footsteps.  I am not condoning the actions of anyone who would pull the trigger before being absolutely certain of their target, but I am saying that it is wise to set yourself up for success.    Never assume your safety is someone else’s responsibility.

I love hunting season; it is full of memories of excitement and anticipation for me.  When my dad got a deer it was a big deal, and I couldn’t help but get caught up in the excitement, even during my 10 years as a recalcitrant teenage vegetarian.  The deer would hang from the rafters of our garage for a time, while it was disassembled into small freezer paper packets labeled in my father’s shaky hand with strips of masking tape.  I was in rapture of these deer, their beautiful fur and antlers an endless source of fascination for my young mind.  The resulting packets were a staple of my childhood winters, when at the hands of my mother they would blossom into venison stews and chili that bubbled alluringly all day in the crockpot.

My dad hasn’t gotten a deer in quite a while now.  He hunts less than he used to, and many of his cousins and hunting buddies have moved out of state.  I’m not quite ready to let go yet though, so I’m putting down my books and picking up a rifle this year, and I’m going hunting with my dad.  No one is more excited than he.

Shelby is a first year graduate student in the Field Naturalist program.  She is very much an animal lover, but reserves the right to occasionally kill and eat them.  She is also a very good shot.  

It’s Getting Hot in Here

By Maddy Morgan

Most of us have probably seen the headlines: “2014 on Track to be Hottest Year on Record,” or “Climate deniers lost for words: 2014 set for hottest year on record.” Yikes! Is it true? If so, what does this mean for us?

The story behind the headlines is based partially on information on the month of August. NASA and NOAA have both confirmed data showing that this August was the warmest August on record. Although New England’s August was relatively mild, temperatures in Central Europe, northern Africa, parts of South America, and western North America exceeded the norm. Ocean temperatures were also warmer than usual.

All this added up to a record-setting August. One month may be no big deal, until you consider that this makes August the 354th consecutive month that is above the 20th century average. And the top 10 hottest complete years on record are 1998, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, and 2013. I’m beginning to see a trend.


If, like me, you hate hot weather and despair at the thought of these rising temperatures, take heart in the map above, which shows most of the United States falling below 20th century averages. If we get too hot we can always relocate to the midwest.

In Search of New England’s Sequoia

By Sam Talbott

Photo page 2I inherited many things from my dad: blue eyes, an affinity for two-cylinder engines, and a passion for woodworking. A set of long-handled carving tools made the journey north from Massachusetts to Vermont with me. I left behind a stout wood lathe, a former resident of the local vocational high school. Between its dark-green metal housing and the exposed 2×4’s of the garage is a well-kept pile of saw dust and wood chips.

If you were to plunge a soil auger into this pile, you’d see a resemblance to “varves” left behind by freezing and thawing cycles of glacial Lake Vermont. Large wood chips give way to fine sawdust—evidence of increasing from 60 to 400 grit sandpaper. The red layers are not redoximorphic reactions, but rather the presence of redwood, Honduran rosewood, and other species not found in the typical New England northern hardwood forests.

Photo page 1The redwood (suspected to be Sequoia sempervirens) made a clandestine trip eastward after being salvaged in the early 1980’s. Large blocks of this wood have been situated around my mom’s house, purporting an insipid appearance. It wasn’t until recently that I discovered the splendid inner grain hidden behind a weathered exterior. Using one of my dad’s bowls as a template, I attempted to turn a nine inch diameter round.

A common theme lurks among my personal ventures: I have no idea what I’m doing. Sometimes the engine starts first kick, other times it takes me 4 hours to realize the fuel switch is off. With woodworking, it is all up to the potential hidden behind layers of bark and cambium. The finished products of Redwood (and similar species) speak for themselves, regardless of form or function. Whittling down a block into two chopsticks would furnish a pair of beautifully extravagant eating utensils.

I speak highly of foreign timber, however Vermont’s forests contain an arguably greater potential than the aforementioned exotics. The gnarliest of trees can have the greatest capacity for charming grain. Burls, or stress-induced growths on trees, are a perfect example of this conjecture. Although challenging and dangerous to turn, the results are worth it. Another woodworking project is borne out of reaction wood—the formation of a hardened elbow along the bole of a tree in response to natural disturbance. These make perfect walking sticks or wooden canes with limited input from the craftsman/woman.

There are approximately 4.46 million acres of forest in Vermont, each one hiding infinite potential for bowls, spoons, and cutting boards. I urge you to go out and salvage from fallen logs and limbs, only a sharp knife and 100 grit sandpaper is required.

Photo page 3

Freshwater Sharks

Snorkeling in frigid waters for a species at-risk

By Levi Old                                                               

Salvelinus confluentusOn a dead-still summer night, I army-crawl upstream.

“We have a large adult!” says Jen.

I rise to one knee and pull the fogged snorkel mask off my head. “A big one?” I mumble in a haze.

“Yeah, really big. Much larger than I’ve ever seen this far up the creek,” she replies, pointing to where it kicked its caudal fin gently against the downstream flow. “It’s right there beside you.”

I cinch the mask on my face, place the snorkel in my mouth, and dunk back into the frigid water:

Twenty-six inches of wildness.

Jen pops her head out of the water and says, “Isn’t that just a beautiful creature?”

She snorkels one side of the creek and I snorkel the other. An assistant in waders walks the creek, tallies our fish sightings and makes sure we do not go hypothermic.

Jen O’Reilly, a biologist for the US Fish and Wildlife Service, leads the recovery effort for the Odell Lake population of bull trout, a Threatened Species under the Endangered Species Act. The recovery team consists of US Forest Service, Oregon Department of Fish and Wildlife, and Trout Unlimited. In order to monitor recovery of bull trout, biologists conduct an annual juvenile count in Trapper Creek, the only known spawning location for this population.

Trapper Creek is a tributary to Odell Lake. In the shadow of Oregon’s Diamond Peak, the lake lies in a glacier-carved basin physically detached from the Deschutes River by a 5,500 year-old lava flow. The flow enclosed the lake, genetically isolating this population of bull trout.

At midnight this past July, ten of us in dry suits and thick neoprene hoodies shimmied up different reaches (Fig. 1) of Trapper Creek. Shallow in most places, the snorkel is more of a crawl and scramble than a leisurely swim upstream. Even in mid-summer Trapper Creek is icy cold.

We closely observed the nooks of each piece of in-stream wood and dove into pools where rapids converged and bubbles enveloped our sightlines. We held dive lights, counted each fish and estimated its size class. We kept our eyes peeled for the creek’s bull trout.

Bull Trout – A species at-risk from Levi Old on Vimeo.

Named for their broad heads, bull trout (Salvelinus confluentus) serve as apex predators in aquatic systems of the West. Often called “Dolly Varden (S. malma),” they are in fact a separate species. Bull trout exist in less than half their historic range and prefer clean, cold waters. As a member of the char genus, they grow to be shark-like beasts in comparison to their trout relatives. Bull trout can measure up to 41 inches and weigh as much as 42 pounds.

Screen Shot 2014-10-24 at 9.34.32 PM
Figure 1: Trapper Creek runs north into Odell Lake. The three primary snorkeling reaches are labeled on the map (Richardson and Jacobs, 2).

The Trapper Creek bull trout population is known as the only adfluvial, non-reservoir population of bull trout in Oregon. During the 20th century, the building of railroads, construction of revetments, and removal of woody debris turned the creek into a large ditch of rushing water, unsuitable for spawning bull trout.

In 2003, this all changed. The recovery team restored the channel to increase spawning and rearing habitat by deconstructing revetments, placing woody debris and rebuilding a meandering channel. The annual snorkel count of juvenile bull trout increased from 26 in 1996 to 150 in 2005. Restoring, sustaining and monitoring native habitat is crucial to the survival of this iconic species.

If you find yourself on western waters, keep an eye out for these stream predators. Light spots of yellow, red and orange cover their dark bodies, and a white margin can be found on the leading edge of their ventral fins. And watch out, anglers: they will steal a hooked fish right off of your line.

Enjoy the video:

Bull Trout – A species at-risk from Levi Old on Vimeo.

Sources:
  • Montana Water Center. (2009). Trapper Creek. Retrieved on October 16, 2014, from http://wildfish.montana.edu/Cases/browse_details.asp?ProjectID=36.
  • Richardson, Shannon and Jacobs, Steve. (2010). Progress Reports. Retrieved on October 16, 2014, from http://oregonstate.edu/dept/ODFW/NativeFish/pdf_files/Odell_BT_Report_final.pdf.

Doing the Runway Strut: Fall 2014

By Ben Lemmond

Not unlike humans, fall fashion is a major event in the fungi kingdom. The theme this fall is retro-seventies blend of yellow, red, tan, and faded orange. Here are some of the superstars I’ve spotted out and about this week. Also, watch the instructional video below on lending a helping hand (or stick) to a puffball in need.

Inside Studying the Outside

Screen Shot 2014-10-17 at 7.59.06 PM

By Kathryn Wrigley

Colors burst forth from the trees.  It is fall.  Or so my Instagram feed, chocked full of apple cider donuts and flaming red trees, portends.

I am soaking in the beige and pale yellow of my desk in the University of Vermont’s Aiken building.  The first-year Field Naturalists appear sporadically to study, still in the midst of their first-semester field courses.  I’m square in the mid-semester of my second year.

My field work from the summer seems like a dream as plot data fills in the squares of Excel spreadsheets – the ostensibly dull side of the field ecologist’s life.  Yet I gain a certain excitement from all the numbers. I’m a detective, a quantifying detective.  I see patterns on the landscape during the summer.  Will they emerge from my data?  Will I find an unexpected pattern?

Since I do not have the brisk fall air to keep me alert and awake, coffee and classical music fuel me.  Oddly enough, this inside work is why I am here at school.  At age 15, I swore to myself I would never work inside.  I worked outside for the next 15 years.  During my time in recreation management, I wondered about the ecological aspects of low-impact recreation.  What were the effects of backcountry rock quarries?  What were the impacts of mountain bike trails?  Were rock climbers threatening rare plants?

For my masters project I delve into low-impact recreation as I explore whether glading, clearing in the trees where skiers can make multiple linked turns, has an effect on wildlife habitat suitability.  I am inside, studying the outside.  Working for all those years outside led me to realize that humans and landscapes cannot be managed separately.  In the spring, I hope to leave this beige and yellow world to work for an organization that focuses on the importance of the ecological and social aspects of conservation.

A Deadly Drink

DSCN2081

Photo by Jessie Griffen

An insect death trap resides in our local wetlands. It’s a grisly tale of plant versus animal, with an unusual twist. Using a modified leaf to create a snare, the Northern Pitcher Plant is one of Vermont’s most unusual and sinister herbs.

Pitcher plants live in wetlands where the peat soil is low in nitrogen. Instead of using extensive root systems or relationships with nitrogen gathering fungi, pitcher plants have evolved to lure, catch, and digest insects to meet their nutritional needs.

From inside its columnar leaf, the pitcher plant emits a sweet smell that attracts insects. Curious bugs fly into the leaf, where they realize that there is no delicious nectar awaiting. When they try to fly out, downward pointing hairs impede their escape. In the pitcher, the insect eventually drowns in a pool of digestive enzymes, insect larvae, flesh flies, and bacteria. This slurry of creatures and chemicals break apart the insect, allowing the pitcher plant to absorbs the precious nutrients that the body contained.

So head on out to your local bog and watch the saga unfold. Witness the demise of a moth or a gnat. You might even see something unusual, like a salamander in a pitcher (photo below), that will make you leave with some new questions and a wild story.

 

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At the bog. Photo by Jessie Griffen

A salamander in a pitcher plant!

A salamander in a pitcher plant. Look for the tail. Photo by Jessie Griffen

 

 

Emma Stuhl is a first year graduate student in the Field Naturalist Program. She is glad that meat eating plants are generally quite small.

Zombie Aspen Leaves

populusleaves-550x410By Bryan Pfeiffer

Rotting and fallen to earth, they might appear dead. But they are not quite dead. They are the undead: zombie aspen leaves.

Find them as you walk the brown autumn paths – yellow leaves with a patch of green tissue radiating from the base of the midrib. Here in Vermont, these are mostly quaking aspen (Populus tremuloides), but I also find the green on big-toothed aspen (P. grandidentata) and, rarely, eastern cottonwood (P. deltoides).

When a friend and I first encountered these some years ago, I collected a few and queried a handful of smart botanists for answers. Many had theories; none had an explanation. It wasn’t until I put a leaf under a dissecting microscope that I found the explanation to be less zombie than something from the film “Alien.” The beast lies within.

populus-caterpillar-moth-550Residing in a tiny pocket of tissue near the base of the green patch is a translucent caterpillar not much more than 2 millimeters in length. It’s feeding in there; I could see the frass (caterpillar poop). With help from Dave Wagner, the renowned entomologist at the University of Connecticut, our critter turns out to be a moth in the family Nepticulidae, probably Ectoedemia argyropeza or most certainly a member of that genus.

“The really cool thing is that the larva secretes an anti-senescent substance that keeps part of the leaf alive – probably a cytokinin,” Dave wrote in an email. Cytokinins are plant hormones that promote cell division. In this case, it seems, the caterpillar keeps part of a leaf alive so that it can keep eating.

This moth is also parthenogenetic; females can produce fertile eggs without help from males, which, as it turns out, are quite rare.

For now, however, the caterpillar will continue to dine in the verdant patch of an otherwise dead leaf. It will pupate for winter. And the tiny adult will emerge to fly in spring. Many species in this genus are black and white with orange scales around the head. But don’t expect to find one. Your best bet for discovering this animal is to watch the trail for patterns in poplar leaves this fall.

And if you’re raking them up, please note that some of those leaves, well, they could be saying, “I’m not dead.”

Making Time for the Leaves

 

The changing leaves in Shelburne, VT

The changing leaves in Shelburne, VT

I was afraid that this year, like so many others, I would lose track of time.  I was afraid I’d spend all of the fall foliage season behind a computer or buried in a book.  I was afraid that in grad school I would have too much homework to do to be able to spend much time outside. But I promised myself: this year I’ll make time. This year I won’t let the seasons change without admiring the gradient between them.  This year will be different.

As it turns out I needn’t have worried.  This year everything is different.  In the Field Naturalist program the brilliantly colored trees form the walls of my classroom, the shimmering late summer sky its ceiling.  We bask in the changing seasons, taking advantage of days warm enough to slog barefoot through a bog and roll up our pants to wade in the cool lake.  We catch salamanders, admire worm holes, and request the name of every plant we come across.  Oh, and everywhere we go we dig a hole.

Our days meander beautifully through each place we go, carefully choreographed to tell a story.  We learn how bedrock affects plant communities, how soils here are different from those in the tropics, and how deep the peat is in Chickering Bog (23 feet!).  This kind of learning is new to me; learning in which we immerse ourselves in our subject matter completely.  I go home each night somehow exhausted and energized at the same time, filling my notebooks with lists of things to investigate further.

As I promised myself, I do make time to go out and enjoy the changing of the seasons outside of class.  I take long rambling walks through the woods with my dog every morning and some evenings.  The only difference is that now I get to justify it as studying.

Shelby is a first year graduate student in the Field Naturalist program.  She enjoys catching toads and salamanders, admiring bugs, climbing talus, and all other explorations of nature.