A Northwoods Almanac for 3/31 – 4/13, 2017
3/13: The bald eagle pair that nests across the Manitowish River from our house began incubating eggs today. The activity around the nest now involves an eagle flying in and settling down into the nest, while another one emerges from lower in the nest and flies off. Bald eagles share the incubation of their eggs, so this trading of tasks is regular throughout the day. Incubation typically lasts around 30 days, so we expect to see the activity around the nest change again around April 13 when they will then be tasked with feeding the chick or chicks. This is, by the way, an early date for nesting – the average date is closer to April 1. Bob Kovar in Manitowish Waters also reported that the eagle pair nesting on his property began incubating the same day.
3/17: Our FOY (First-Of-Year) red-winged blackbirds returned to our feeders in Manitowish, as did an American tree sparrow.
3/23: Our FOY white-throated sparrows returned to Manitowish.
3/24: Nancy Burns spotted the FOY hooded mergansers on the Manitowish River.
3/25: Sharon Lintereur in Lake Tomahawk saw movement in their owl nesting box, and it turns out that for the second consecutive year, a pair of barred owls are nesting there. Barred owls nest most often in deciduous trees, primarily in cavities formed by disease, broken branches, or cavities in the top of broken trees (snags). However, they will use open stick nests built by hawks, crows, ravens, or squirrels, too. They also readily take to nest boxes, as is the case at the Lintereur home. Incubation is done solely by the female and is usually about a month, with an average clutch size of 2 to 3 eggs. If more than 3 eggs are laid, each on successive days, the youngest of the brood often is underweight and weak, and may be eaten by its nestmates.
|photo by Sharon Lintereur|
3/25: Mary and I spotted our FOY common goldeneyes, red-breasted mergansers, and common mergansers in Marquette, MI, on Lake Superior.
3/27: Our FOY common grackles appeared at our feeders in Manitowish.
On the Horizon
Numerous species of birds have migrated into southern Wisconsin and most are poised to continue their flights into the Northwoods as the weather warms. Keeping records on when various species return is all part of phenology, or the study of the orderly timing and progression of natural events. Others define it as the study of biological cycles and seasonal rhythms. It’s nature’s calendar. I encourage you to keep a calendar of your first sightings, from ice-off on your lake, to the first birds and flowers, to various temperature and rainfall recordings. Relying on our memories, at least for those of us without photographic memories, is a sure way to ruin otherwise. Then pass on your records to the next person who will own your home, so they know what to look for and when.
Five Drummers Drumming
Woodpeckers are beginning to drum regularly on trees around our home, the males now establishing territories and beginning to woo a mate. If you pay attention to the duration, speed, and volume of the drumming, you can identify the species by the drum pattern. We only have five common woodpeckers in our area – pileated, hairy, downy, northern flicker, and yellow-bellied sapsucker – so it’s not too daunting. You may also hear red-bellied woodpeckers which continue to slowly move north into the Lakeland region, as well as red-headed woodpeckers which have become less common. And if you are particularly blessed, you could hear a black-backed woodpecker. But we are at the southern-most edge of their range, and they’re rare.
The drumming for territories and mates is different from that of the arrhythmic tapping heard from woodpeckers as they excavate nests and search for insects. The drumming from yellow-bellied sapsuckers is an easy one to start with because it starts strong with several relatively fast taps, then slows down, and finally fades out at the end. It can be very irregular, often changing in successive drumrolls – you can think of it as a Morse code: Tap-Tap-Tap…tap-tap-tap . . . tap . . . tap . . . tap.
The pileated is the power drummer of the crew, pounding out a crescendo that is deep and resonant, lasting for three seconds or more. Both genders drum, but the females less frequently. Famed ornithologist George Sutton described the sound as a repeated sequence of “an introductory, rapidly given ; then a pause, followed by three distinct blows; another pause; and two concluding blows.” It’s the volume that gives this one away without a doubt, and you can literally hear the hollowness of the tree.
|pileated chicks in nesting cavity|
Things get a little dicier now in identifying the drumming patterns. The drumming of northern flickers has been described as “a miniature pneumatic drill,” produced by even, rapid blows. The drum roll only averages a little more than a second long, but contains 25 beats in a roll. Like many woodpeckers, flickers will often drum on a metal surface. One flicker in Wyoming beat on the cowling of an abandoned farm tractor and could be heard almost a half-mile away.
The hairy woodpecker drums at a relatively steady rate, but more rapidly and with longer pauses than the downy woodpecker. Its drumroll lasts about a second and has 26 beats – it goes by so fast that you can’t pick out the individual taps – whereas a downy’s drumroll lasts three-quarters of a second and averages 13 beats. Here you can just pick out each tap.
The downy also loves to drum more, offering 9 to 16 drumrolls a minute versus the less enthusiastic hairy which only drums 4 to 9 times a minute.
Both sexes drum in all these species for a variety of reasons:
1. To defend a territory
2. As part of a courtship
3. To solicit copulation
4. To summon a mate from distance away
5. To communicate their location to a mate or in response to a nest intruder
6. Or for reasons no one will ever know
Drumming does occur year-round in woodpeckers, but it’s much more intensive in spring. While species identification from drumming can be done with practice, if I had a nickel for every misidentification I’ve made of birds, I’d be a wealthy man.
Saw-whet Owls Calling
I’ve yet to hear a saw-whet owl “singing,” but now is the time to go out after dark and listen for their monotonous tooting. While saw-whets produce a series of different calls, the one most often heard is the “advertising call,” which is an endless loop of whistled “toots” on a constant pitch. The call comes at a rate of about two per second and sounds, and when researchers say it’s monotonous, they really mean monotonous – the song can literally go on for an hour or more.
|saw-whet owl range map|
Jupiter will be at its closest to the Earth on 4/7 and brighter than at any other time this year, and is also visible all night. You should be able to see Jupiter’s four moons with a good pair of binoculars. If you can’t, this is a good excuse to buy that spotting scope you’ve always wanted – see www.eagleoptics.com. The moons are often called Galilean moons for Galileo who discovered them in 1610.
Galileo was employed by Cosimo de’ Medici, the Grand Duke of Tuscany. In seeking further patronage from this wealthy family, he used the discovery of the moons to name them the “Medician Stars” after the Medici Clan. He wrote a dedication letter to the Duke in which he said, “Scarcely have the immortal graces of your soul begun to shine forth on earth than bright stars offer themselves in the heaven which like tongues will speak of and celebrate your most excellent virtues for all time. Behold, therefore, four stars reserved for your illustrious name . . .” It occurs to me this practice continues in our time, but is used to gain money by naming stadiums after corporations, not moons after Dukes.
On 4/10, look for Jupiter in the southeast just two degrees below the nearly full moon. Full moon occurs the next day, 4/11.
For planet viewing in April, look after dusk for Mars very low in the western twilight – it’s lost by late-month. Jupiter is very bright in the southeast. Before dawn, look for Venus very low in the eastern twilight and climbing. Look also for Saturn in the south (Saturn rises after 1 a.m. in the ESE if you are wandering around at that hour). Saturn’s rings are tilted at nearly 27 degrees from edge-on.
April 12 marks the anniversary of the first human in space – Yuri Gagarin in 1961 from Russia – when the race for space really heated up.
Thought for the Week
“Wisdom grows as a river grows, from the accumulation of many small things.” Kathleen Dean Moore
Please share your outdoor sightings and thoughts: call 715-476-2828, e-mail at firstname.lastname@example.org, snail-mail at 4245N Hwy. 47, Mercer, WI