NWA 8/31/12

A Northwoods Almanac for 8/31 – 9/13/12

by John Bates

Nighthawk Migration

Common nighthawks are now migrating south, and birders from all around the state have been reporting seeing them in large flocks up to 1,000. Mary and I were in Mercer on Saturday, 8/25, eating dinner outside with friends when a flock of 18 came overhead, followed by irregular groups of two to six over the following several hours.

In the nightjar family (so-called for the "jarring" sounds made by the male when “booming” at night), or what is also called the goatsucker family (so-called from the notion that the birds suckled goats (what were those ancients drinking?!)), the common nighthawk is most often observed on the wing, hawking insects at dusk and dawn in both urban and rural areas. It’s unique for its loud, nasal peent calls, spectacular booming courtship dives, and erratic, almost bat-like flight. The name “nighthawk” is a complete misnomer because it is actually most active at dawn and dusk, not night, and like other members of its family, is not related whatsoever to the hawks.

Nighthawks nest most often on open ground, gravel beaches, rocky outcrops, and burned-over woodlands, but are also well known for nesting on flat gravel roofs in cities. They make no nest, but simply lay their eggs directly on the ground, depending on their cryptic plumage to make them difficult to see.

Nighthawks migrate both day and night, but most flights are observed during early evening in late summer. They fly a great distance between their breeding range and their winter range, traveling one of the longest migration routes of any North American bird. Their fall departures begin as early as late July in both northern and southern portions of the breeding range in the U.S. and Canada, and individuals become quite gregarious during fall migration, sometimes gathering in flocks of thousands.

They’re heading south so early because they require a constant supply of insects, and historically, we would commonly have frosts in late August which would wipe out the insect population.

They forage under low light conditions at dusk and dawn, and it’s thought that their vision may be aided by presence of a tapeta lucidum, a reflective structure within the choroid of the eye which improves night vision by reflecting light back to the retina.

They’re “good” guys, eating more than 50 insect species, the majority of which are queen ants, beetles, caddisflies, and moths. An analysis of one nighthawk’s stomach found 2,175 ants and another 500 mosquitoes.

Lack of Mosquitoes This Summer?

            Numerous people have questioned why there has been a lack of mosquitoes this summer. My best thought is that it has simply been a relatively dry year, particularly this early spring. In walking some forest trails recently, I noticed that most small woodland ponds are little more than mud holes. And while many of these ponds are ephemeral and are meant to dry up as the summer progresses, others are also usually “permanent,” and their lack of water is a good indicator to me of how relatively dry it’s been.

Hummers Leaving

            The first weeks of September are a farewell to many beloved bird species, and none more so than ruby-throated hummingbirds. Typically, they’ve departed by 9/10, and often earlier. Please leave your feeders up for another two weeks, however, in order to provide food for those hummers that will still be migrating south through our area.

            Speaking of hummingbirds, John Reichling in Winchester has had a downy woodpecker drinking from his hummingbird feeder all summer. It drinks for 5 to 10 minutes, and comes every day. Woodpeckers have an extendable tongue like hummingbirds, so that must be how it is getting fluid from the rather small holes of the feeder.

Hawks Leaving, Too

            The Northwoods’ most common hawk, the broad-winged hawk, peaks in migration in mid-September. Most migrate during a narrow two-week window lasting from about 9/10 – 9/23 when they come through in massive numbers. And there’s no better place in the Midwest to see them than in Duluth. I highly recommend visiting Duluth’s Hawk Ridge over the weekend of 9/15-16 when they hold their annual Hawk Weekend festival. If the weather is right, many thousands of broad-wingeds are likely to pass overhead. See www.hawkridge.org for more details.

Gluttony

Mary Madsen on Twin Island Lake in Presque Isle sent me a photo of a chipmunk stuffing its cheeks with dogwood berries and noted: “Not only the birds were enjoying the berries of our Pagoda Dogwood! The tree was picked bare in just a couple of days by a variety of birds.”

            Mary and I have made some pretty good elderberry jam the last two Augusts from our elderberry bushes, but this year the birds devoured nearly all of our elderberries in just a few days. Most surprising to me were the many white-throated sparrows that were part of the horde – I wasn’t aware that sparrows ate that many fruits!

            Our mountain ash tree is also loaded this year, and many robins and cedar waxwings have been gradually stripping it. One morning I watched a juvenile robin land right next to an adult cedar waxwing and open its mouth like it expected to be fed by the waxwing! The waxwing looked at it, then turned away, and I suspect if I was able to detect disgust in a bird, I would have seen it then.

            This is the time for many birds to build up fat for migration, so while we humans look forward to the autumn harvest, it’s clearly not just a human event.

Mushroom Time!

The 2nd edition of Fascinating Fungi of the Northwoods by Cora Mollen and Larry Weber was recently released with 38 additional species descriptions and accompanying images. Cora’s book includes notations regarding edibility of many of the featured mushrooms and is an excellent introduction to the mushroom world. Mary and I use Cora’s book as our identification guide to the most common mushrooms in the Northwoods, and we only wish we were one-tenth as expert on mushrooms as Cora.

Cora lives in St. Germain and helped organize a mushroom club there many years ago, which has now expanded to 60 members. If you’ve ever had an interest in learning more about mushrooms, I highly recommend joining the club, or at least participating in some of their events. See www.northstatemycologicalclub.org for more information.

Hemp Nettle

            In hiking the beautiful trails at Van Vliet Hemlocks last week, Mary and I discovered a new wildflower for us – hemp nettle. The plant was very common throughout the stand, which made us wonder rather uneasily about its origins. Unfortunately, our concerns turned out to be justified – hemp nettle is yet another exotic and invasive species that should be removed when found.

Hemp nettle (Galeopsis tetrahit), one of many species in the mint family, has simple, toothed, and opposite leaves, with a bristly stem. Introduced as early as the 1940s, it was thought to be a disturbed soil, roadside/field/yard kind of a plant. However, in recent years it has begun to spread from forest roadsides into adjacent forests along roads and trails, and is now clearly a serious invasive. It also is found very widely in hemlock-hardwood forests of northern Wisconsin, which is the exact habitat-type of the Van Vliet Hemlocks.

An annual, hemp nettle depends completely on seed production to increase on a site – there’s no evidence of vegetative reproduction. It is likely that machinery operation in the forest exposes mineral soil, aiding the spread of this species. Forest soils that have been cleared of the layer of decomposing leaves by alien earthworms also appear more favorable to the spread of hemp nettle.

Celestial Events

            Full moon tonight, 8/31. For planet-watching in September, look after dusk for both Saturn and Mars low in the southwest. Before dawn, look for Venus brilliant and low in the east, and Jupiter almost as bright rising in the northeast.

            On 9/8, look for Jupiter just above the last quarter moon. On 9/12, look for Venus four degrees north of the crescent moon.

            We’re heading at high speed for the autumn equinox – enjoy the longer daylight hours while you can!

Please share your outdoor sightings and thoughts: call me at 715-476-2828, drop me an e-mail at manitowish@centurytel.net, or snail-mail me at 4245N Hwy. 47, Mercer, WI 54547.