A
Northwoods Almanac for April 14 – 27, 2017
Loons
Returning
Over
30,000 adult loons reside in the U.S., half of which nest in MN, WI and MI. Wisconsin
alone has an estimated summer population of about 4,000 adults. Of those, the
Lakeland region is home to the second largest loon population in the Midwest,
and they’re returning now. Up to ice-out, “our” loon pairs content themselves
with overflights of their territories to look for open water. In the meantime,
they wait (mostly along the Wisconsin River) the lakes to open-up, though a
lake may be only partially open and the loons will still land.
Since
1991, researchers have banded over 3,600 adult loons and chicks in northern
Wisconsin, providing a wealth of information on when loons leave for their
autumn migration, where their migratory routes take them, where they spend
their winters, and much, much more. A far smaller number have had satellite
radio transmitters surgically implanted in them, allowing biologists to track
their daily movements.
This
extensive banding and observation of marked loons has shown that over-wintering
adult survivorship is high and more than half of chicks born here return to the
area as adults. Loons first return to their breeding grounds at age 2 to 4
years of age, with males tending to return nearer to their natal (birthplace)
territory than females.
Both
sexes tend to wander as “floaters” and use many different lakes for 2 to 3
years before either founding or acquiring a territory. Males and females both show
a striking age-dependent pattern in the means they use to gain a territory:
when 4-5 years old, they usually try to settle in a vacant territory with a
mate and thus create a new territory. But finding a vacant territory these days
is quite uncommon unless the adult pair on a lake fail to return from their
winter on the Gulf.
Thus,
nearly all desirable territories are already spoken for, and most younger loons
have no choice but to acquire their territories by force. If the loons have not
created a new territory by 6 to 8 years of age, they usually attempt to seize a
territory from an established owner after a violent territorial battle. Among
males, about one-third of these battles result in the death of the displaced
male owner. Displaced females are more likely to leave the battle before being
killed, but then typically will still need to fight to acquire a new territory.
These territorial evictions are about equally frequent in males and
females.
During
these battles, the response of the other member of the breeding pair is stand
aside. Walter Piper, who has studied loons in our area for 25 years, has
observed many of these battles and has learned that females, which are about
20% smaller than males, can’t help their mate avoid eviction – they’re too
small to make a difference in the battle. Their size, though, ensures they are
protected. Piper notes, however, that males might be expected to help their female
mate drive off a would-be usurper, yet Piper and his crew have never observed a
male teaming up with his mate to drive off a potential usurper. Why
not help out? Well, while loons are monogamous, they are married more to their
territory than their mate. As Piper notes, “Perhaps males are better off with a
mate that fights strongly (such as a proven usurper), since having a
vigorous mate ensures future years of eviction-free breeding. It is a bit sad
and selfish to say it, but if your mate is vulnerable to eviction, it is
probably best to let her fend for herself than to intercede and save her.”
Obviously, the same would also hold true for females not jumping in to help
their male counterparts.
Peepers,
Wood Frogs, and Chorus Frogs Singing
It’s
frog time, and as soon as we have warm nights in the high 30s and the ground
thaws, spring peepers, wood frogs, and chorus frogs will emerge from their
woodland hibernation and begin their breeding clamor. Fishless temporary
wetlands (called vernal pools or ephemeral wetlands) are ideal for breeding –
the water warms quickly and the frogs can lay their eggs in relative safety
from predators.
Spring peepers inflate their throat pouch to
nearly the size of their body and use it to push air over their vocal cords,
making a sound when they both inhale and exhale. Each call rises in a crescendo
until collectively there is total tumult in the pond. The frogs engage in
duets, trios, quartets, what one naturalist describes as “nature’s choir
fortissimo.”
Peepers can be heard from as far as a mile to
two away depending on the number of peepers in the chorus. And when you hear
them, you can bank on spring being here, at least “spring” as defined very
loosely in the Northwoods.
Mating
Strategies – Don’t These Birds Have Any Morals?
For
birds, mating isn’t about sex, it’s about leaving behind a maximum number of
offspring and contributing to the gene pool. So, morals don’t play into the
equation. However, most bird species mate monogamously, which would appear to
meet the family values test of humans. In fact, monogamy occurs in more than 90
percent of avian species. Sounds good on the surface! The problem is biologists
have discovered from blood tests that chicks are often of mixed parentage, and
that most species of songbirds participate in “extra-pair copulations (EPCs).”
Paired males commonly copulate with
other females, but females also initiate EPCs by flying into another male’s
territory. So, there’s lots of hanky-panky going on, but under the appearance
of a monogamous relationship. Think of various soap operas – “Days of Our
Lives,” “Dallas,” etc.
Polygamy,
where a male or female pairs with two or more members of the opposite sex,
occurs where birds can monopolize a desirable habitat, or one gender can
monopolize a group of the opposite sex. When a male mates with two or more
females, it’s called polygyny. Pheasants fit this bill, the male attracting a
harem of females to his desirable territory, protecting and fertilizing them,
but playing no part in rearing the young. Of North America’s 278 breeding songbirds,
only 14 are polygnous - marsh wrens, red-winged blackbirds, indigo buntings,
and lark buntings are other examples.
In only
a few cases, females pair with more than one male, a practice called polyandry.
Spotted sandpipers, phalaropes, and acorn woodpeckers are examples. A spotted
sandpiper female is larger and more aggressive than a male. She mates with one
male, lays a clutch of eggs, leaves him to incubate and rear them, and then
pairs with other males, repeating the process again and again. Because she
mates with multiple males, the incubating males often raise chicks that belong
to their competitors. Thankfully, birds don’t have custody battles and alimony
– think of the legal fees.
Then
there are birds that are classified simply as promiscuous. In very good
habitat, the female only needs the male for his sperm, so she chooses from a
host of males happy to display themselves in the same area. For example, prairie
chickens and sharp-tailed grouse mate on leks, which are tiny territories where
the males gather, dance and call madly, and often fight, all in hopes they will
be selected by a very discerning female. Think wild bar scene. She walks among
them, considering, considering, then briefly has a fling, and off she goes to
build her nest and carry out all the nesting duties, while the males continue
their dancing on the lek. Older males hold territories near the center of the
lek, leaving younger males to patrol the periphery and continually challenge
the older males for a spot in the choice middle.
Different
strokes for different folks - it’s all about taking advantage of habitat
conditions and individual reproductive strengths with the goal of advancing the
species.
Sightings
3/28: Robins began their pre-dawn chorusing in
Manitowish. Callie and I heard two pairs of sandhill cranes dueting in Powell
Marsh.
3/29: FOY (first-of-year) Juncos and tree sparrows
arrived in Manitowish.
3/30: FOY fox sparrows and rusty blackbirds returned to
our backyard in Manitowish. We also spotted our FOY common and hooded
mergansers on the Manitowish River.
3/31: Sarah Krembs heard the FOY American woodcock near
her home in Manitowish Waters.
Celestial
Events
Today,
4/14, we’re now enjoying 13.5 hours of daylight.
On 4/16 and 4/17, look before dawn for Saturn
near the waning gibbous moon.
According to Woody Hagge’s 41 years of data,
4/16 also marks the average ice-out date for Foster Lake in Hazelhurst. At 39
acres and a maximum depth of 38 feet, Foster Lake represents a relatively
“average” lake in our area. In general, however, larger, deeper lakes will keep
their ice longer, while smaller, shallower lakes will lose their ice earlier.
Foster Lake now averages 141 days, or 20 weeks, of ice cover.
Around
4/21, the average low temperature for the Lakeland area will hit 32°. Minocqua
thus averages 182 days with low temperatures above freezing.
The peak
Lyrid meteor shower occurs in the predawn on 4/22 and averages 10 to 20 meteors
per hours.
Finally,
before dawn on 4/23, look for Venus near the waning crescent moon.
Redwoods!
 |
| our daughters, Eowyn and Callie, within the redwoods |
Mary, Callie, and I flew out last
week and joined our oldest daughter Eowyn for a visit to the Jedidiah Smith
Redwood State Forest near the Oregon border. More on this in a later column,
but this trip has likely broken the record for the number of times “WOW” has
been said in any given hour. One of the old-growth redwood groves in the park
totals 5,000 acres, and includes the world’s largest, though not tallest, coast
redwood (Sequoia sempervirens),
measuring 20 feet in diameter and 340 feet tall. These are the largest living
trees on Earth along with their brethren the sequoias (Sequoia
giganteium).
 |
| note the single trillium within the mosses |
John
Steinbeck wrote in Travels with Charley,
“The redwoods, once seen, leave a mark or create a vision that
stays with you always. No one has ever successfully painted or photographed a
redwood tree. The feeling they produce is not transferable. From them comes
silence and awe. It's not only their unbelievable stature, nor the color which
seems to shift and vary under your eyes, no, they are not like any trees we
know, they are ambassadors from another time.”
Thought
for the Week
“Fueled . . . by a million wings of fire the rocket tore a tunnel through the sky and everybody cheered.
Fueled . . . only by a thought from God, the seedling urged its way through the
thickness of black and, as it pierced the heavy ceiling of soil and launched
itself up into outer space . . . no one even clapped” – Marcie Hans. Let’s
remember to clap.
Please share
your outdoor sightings and thoughts: call 715-476-2828, e-mail at manitowish@centurytel.net, snail-mail at 4245N Hwy. 47, Mercer,
WI, or see my blog at www.manitowishriver.blogspot.com
