A Northwoods Almanac
for 11/27 – 12/10, 2015
Winter Finch Forecast
Every autumn, Ron Pittaway, an Ontario ornithologist, publishes his
“winter finch forecast,” an attempt to foretell what birds that usually winter
in Canada might be seen wintering in the northern U.S. Here’s a summary, species by species:
Common redpoll: like last winter, common redpolls will likely move south
because birch seed crops are low to average in northern Canada.
Evening grosbeak: a small flight of evening grosbeaks is expected
because of increasing numbers due to expanding spruce budworm outbreaks in
Quebec.
Pine grosbeak: these beautiful birds should move south in small numbers
because the mountain-ash berry crop is below average in northern Ontario.
Purple finches: many should migrate
south out of Ontario this fall because cone and deciduous tree seed crops are
generally low in northern Ontario.
Pine siskins: last winter, pine
siskins were everywhere in very high numbers. This winter expect very few
siskins because they will be concentrated in western Canada and the northern
New England States which have heavy spruce cone crops.
Bohemian Waxwings!
Bohemian waxwings aren’t a finch,
but they, too, occasionally drop down into northern Wisconsin when mountain ash
berries, their favorite food, are poor. This winter we can expect a moderate
southward and eastward flight because mountain-ash berry crops are average in
the boreal forest. On 11/19, we had 20 bohemian
waxwings feeding in one of our crabapple trees, which is an early appearance
for them.
Snowy Owls
Chad McGrath and MJ Slone sent me
photos of a snowy owl that they observed at Springstead Landing on the
Turtle-Flambeau Flowage. This may or may not be the same bird that was reported
eating a duck in the same area on 10/27.
As of 11/9, roughly 72 snowy owls
have been reported from 37 Wisconsin counties, compared to five as of this date
in 2014 and none in 2013.
I sent
the photos to Ryan Brady, an avian research scientist for the WDNR in Ashland
and my “go-to” guy for bird identification, in hopes that he could say what
gender and age it might be. He responded, “We can't accurately age and sex
these guys based solely on pics of plumage. See the Popular Resources tab of
our snowy owl page: http://dnr.wi.gov/topic/WildlifeHabitat/SnowyOwls.html.
“With
that said, it's most consistent with a young male – I can't be certain though.
Many birds this year aren't doing very well, and the first signs seem to be
roosting in odd places and allowing exceptionally close approach. That appears
to be the case here.”
Oregon Old-growth
When Mary and I spent two weeks in October on a
wrtier/artist residency in an old-growth forest in Oregon, we reveled in the
size of the trees (see the photos of one of our biggest white pines in
Wisconsin compared to a large Douglas fir out there). One theory on why the
trees in that area are so large is that while their annual rainfall is around
95 inches, they only receive an inch a month during the summer – the area
receives 90% of its rain in the winter! The trees are thus thought to grow so
large as a means of storing sufficient water to get them through the dry
summer, much like a camel.
Rough-skinned Newts
One salamander we frequently saw while hiking in the
Oregon old-growth was the rough-skinned newt, which is plain brown on top, but
brilliantly orange on its underside. These creatures were quite placid, moving
slowly on numerous trails. I picked one up just to see what it felt like,
examined it a bit, and then set it back down. The newt seemed quite unfazed by
my handling it.
Later on I learned this was not the wisest thing I’d
ever done. Rough-skinned newts secrete one of the most poisonous substances
known, a neurotoxin called tetrodotoxin (TTX). The poison occurs in their skin,
muscles, and blood, and can cause death in many animals, including humans, if
eaten in sufficient quantity. “Sufficient quantity” turns out to be not much –
one study estimated that 25,000 mice could be killed from the skin of one
rough-skinned newt. TTX blocks signals in the nervous system, leading to a
quick death. In fact, TTX is 10,000 times deadlier than cyanide.
Fortunately, it turns out that this poison can’t be
absorbed through the skin, but it can enter through a mucous membrane, like the
eyes, or through a cut in the skin. Luckily I didn’t have any wounds on my hand
or rub my eyes afterwards! Rough-skinned
newts contain enough poison to kill people, a case in point being being a
29-year-old Oregon man who in 1979, on a drunken dare, swallowed a
rough-skinned newt and died a few hours later (see www.darwinawards.com for
more guys like this).
Apparently potential predators are quite aware of the
newt’s poison, and if they’re not, the newt assumes a swaybacked
defensive pose, closing its eyes, extending its limbs to the sides, and holding
its tail curled up over the body, thus exposing its bright orange underside as
a very serious warning. Scientists have tested 30 potential predators of newts,
from belted kingfishers to great blue herons to bullfrogs and fish, and have
found in every case that the newt killed them.
What’s most remarkable, however, is
that common garter snakes in that area have evolved an extreme resistance to
the poison and prey on rough-skinned newts, their only known predator. In
response, the newts have continually upped their production of TTX, which has
resulted in the garter snakes evolving a yet higher resistance again and again,
in effect engaging in what biologists have termed “an evolutionary arms race.”
In evolutionary theory, their
relationship is a prime example of co-evolution. The
mutations in the snake’s genes that confer resistance to the toxin result in a
selective pressure that favor more toxic newts. The more toxic newt then
applies a selective pressure favoring snakes with even greater resistance. This
evolutionary counterpunching, each continually adapting to the other, has
resulted in the newts producing levels of toxin far in excess of what is needed
to kill any other conceivable predator.
The newt’s use of toxins goes yet another step.
Researchers found that the females load their eggs that they lay in ponds with
TTX to dissuade predators. Dragonfly larvae and other aquatic predators that eat
plenty of eggs of other species from ponds won’t touch the newt eggs.
But, like the garter snake, there’s one exception.
Caddisfly larvae turned out to relish the newt eggs, actually growing bigger if
they were supplied with newt eggs by researchers, even though the researchers
estimate there’s enough TTX in one newt egg to kill somewhere between 500 and
3700 caddisflies. Thus, it appears that the caddisflies have evolved high
levels of resistance much like the garter snakes.
Ice-up and Immature
Loons
As of 11/20, folks in our area are
still observing juvenile loons on open water. In northern Minnesota, of seven
juvenile loons implanted with satellite transmitters this summer, all were still
on their natal lakes as of this date.
Researchers from the Upper Midwest
Environmental Sciences Center (UMESC) also implanted satellite transmitters in
juvenile loons in the summer of 2014. Of those 15 juveniles, their website map
indicates that only 3 are known to be alive, 8 have died, and the status of the
remaining 4 is unknown. To follow these birds, go to:
Eagles Nest Building
Every fall Mary and I observe the
eagle pair across the river from us carrying building materials to their nest,
an activity seemingly out of synch with the breeding season. However, this is
typical behavior, apparently having to do with the rapid change in daylight
which spurs hormone production. Ruffed grouse
frequently drum in the fall, many birds still sing (though more weakly and
intermittently), prairie chickens occasionally dance, all likely because the
amount of daylight they’re experiencing in the fall is similar to the spring.
Climate Change – CO2 400ppm
Benchmark Eclipsed Permanently
NOAA announced on 11/18 that global
temperatures in October 2015 showed the largest departure from the long-term
average for any month going back to 1880. A week earlier, 11/11, a crucial
milestone in global climate was also reached. The daily average concentration
of carbon dioxide in the air that day at Hawaii’s Mauna Loa Observatory was 399
parts per million. On 11/12, it rose to 410 ppm, and researchers believe that
we’ll never see another day with the daily Mauna Loa CO2 reading below 400 ppm.
The 400-ppm mark was first reached
in May, 2013, but only for a few days, during the annual peak of atmospheric
CO2. Along with the year-on-year rise due to fossil-fuel use, CO2 ebbs and
flows in the atmosphere each year as vegetation grows and dies back in the
Northern Hemisphere. In 2014, the daily Mauna Loa readings stayed above 400 ppm
for more than three months. This year they rose above 400 ppm even longer, only
dipping below 400 ppm in August before climbing back above the benchmark this
month. And there’s no end in sight to this increase
– we’re adding 2 ppm of CO2 to the atmosphere every year.
A few years back, there was a
concerted effort to reduce CO2 to 350 ppm, a concentration considered by most
scientists to be the “safe” level of CO2. Instead, we’re continuing our global
climate experiment into further uncharted territory.
Celestial Events
On the
morning of 12/3, look for Jupiter above the waning crescent moon. On the
morning of 12/6, Mars will be right above the moon. On the morning of 12/7,
Venus will be just below the moon.
