A Northwoods Almanac for 9/30 – 10/13, 2011
Hawks Migrating
Peak numbers of migrating hawks, primarily broad-winged hawks, have been passing through Wisconsin over the last two weeks. On 9/15, the hawk counters at Hawk Ridge in Duluth tallied a high of 13,276 raptors, of which 96% (12,790) were broad-wings. The next best day, 9/19, they counted 7,432 raptors, with broad-wings again dominating the count at 93% (6,881) of the total. For the month of September, at least as of 9/24, the total count stood at 46,218.
These are rather pedestrian numbers for Hawk Ridge. The record count for September occurred in 2003 when 174,830 raptors were observed.
Raptors, of course, aren’t the only birds that fly over the ridge. On 9/23, the counters also tallied 5,179 migrating non-raptors, including 2,718 blue jays, 595 cedar waxwings, 225 pine siskins, 148 American robins, 130 yellow-rumped warblers, and 109 American goldfinches.
It’s a busy place, and still highly worth a visit in the next few weeks. For directions, see www.hawkridge.org.
Cranes Staging
Imagine the sound and the sight of thousands of greater sandhill cranes flying and calling, all in a whirl of action in one concentrated area. That’s what awaits you at an autumn sandhill crane staging ground. These staging areas are traditional sites that the cranes return to every fall, but don't use in the spring in their haste to reach their breeding grounds. Here in autumn fields and marshes, the cranes may remain for up to a month, feeding and loafing in little haste to finish their migration south.
No one can really say why cranes stage at all. During spring, sandhills drive away any intruders who venture near their territories. But in September, crane pairs socialize and feed together in the same fields, often gathering together in large flocks. The availability of food, safety, and the familiarity of one area, plus the loss of other areas that may have been used historically for staging, all contribute to funneling large numbers into one spot.
Best viewing is in early morning before they scatter to feed, and then in late afternoon/early evening when they come all back together to roost. By late fall, the exodus to southern states like Texas, Georgia, and Florida begins with the cranes usually sailing a mile or more above the ground, riding like gliders on the northerly winds.
In the upper Midwest, we are not blessed with major staging sites, but we do have a number of excellent smaller sites, island stepping stones as such, that still draw in thousands of cranes. In Wisconsin, the 9,150-acre Sandhill Wildlife Demonstration Area near Babcock hosts flocks of up to 1,000 sandhills from mid-October to mid-November. Crex Meadows often attracts up to 6,000 staging cranes by late October. Navarino WMA (Wildlife Management Area), White River Marsh WMA, Comstock Marsh State Natural Area, and Grand River Marsh WMA are also traditional fall staging areas worth visiting.
Turtles Going into Hibernation
Beth and Cal Huizenga found a nest of baby snapping turtles on 9/24 in Presque Isle and sent a photo. It’s certainly past time for the hatchlings to emerge. While adult snappers overwinter in shallow water, and may either sit on the bottom or shelter themselves by digging into the mud, the hatchlings can spend the winter either in their sandy terrestrial nest or in the water. It all depends on how warm and dry the weather was during the summer. Snapper eggs are typically laid in mid-June, but the eggs will hatch in anywhere from 50 to 125 days. More females hatch during warmer temperatures, and more males hatch during cooler temperatures. Likewise, hatching is accelerated by warm weather and delayed by cooler weather. Hatchlings that overwinter in their nest at our latitude where the ground freezes hard don’t survive well.
Hatchling turtles use their egg tooth and claws to break out of their shell, and then have to dig their way out of the nest and find water. When they emerge, they’re 1 to 1.25 inches in length, about the size of a quarter, and highly vulnerable to predation. From any given clutch of eggs, 60% to 100% of the young may be lost to predators, and those that make it to the water are then prey for large fish, large frogs, northern water snakes, and some bird species. It’s a wonder any make it all.
Snappers are slow to mature, reaching sexual maturity in 5 to 7 years. An amazing 60% of the individuals reaching maturity will live to age 50. Unlike in any other species, survivorship does not decrease with age. Longevities over 100 years can be expected especially in the northern populations where their active season is much shorter.
Blue Jay Migration
It’s a surprise to most folks that blue jays migrate, but the many thousands of migrating jays counted at Hawk Ridge every year gives clear evidence that they do. Interestingly, however, nearly all aspects of blue jay migration are poorly understood. Some jays remain in their breeding range year-round, while others migrate. However, the distance traveled by migrants is highly variable, and, in most areas, most jays appear to reside all year – the best estimate is that less than 20% of any jay population migrates even in northern parts of their range.
Some research suggests that migration may be influenced by fluctuations in mast (acorn) abundance. Other studies point to younger jays being the ones that migrate – one researcher working on the shore of eastern Lake Superior calculated the ages of 1,271 blue jays he captured during a six-year study of spring migration and found 72% to be second-year birds. However, the proportion of second-year birds captured ranged from 2% to 90% over the six years, so age as a factor in migration remains unclear.
Plus, individual blue jays act differently from year to year. An adult jay that breeds at one location may breed substantially farther south in subsequent years. Likewise, jays captured and marked as adults during winter have been recaptured substantially farther south in subsequent winters.
So, what can be said to summarize the migration behavior of blue jays? Very little! Clearly they are all not hard-wired to migrate, yet some do.
Sightings
Sue Drum in Presque Isle sent the following note (see her photo): “After nine years spent watching red squirrels fight over the sunflower seeds in a dish on our deck, the extraordinary suddenly happened. Two red squirrels, after a brief squabble, occupied the dish together, peacefully. Because of their small size we guess they may be siblings.”
Sandra Wenzel observed an albino blue jay among a flock of six other normally-colored blue jays at her feeders in Sayner.
Celestial Events
For viewing planets in October, look at dusk for Venus very low in the southwest twilight and Jupiter rising around 7 p.m. in the northeast. Before dawn, look for Mars high in the southeast and Saturn emerging also in the southeast but not until the last week of the month.
The Draconid meteor shower peaks on 10/8, averaging a handful of languid meteors per hour in most years. However, earlier this year, Canadian astronomer Paul Wiegert predicted that this year, fiery Draco might spew forth up to a thousand meteors in a single hour. In 1933 and 1946, the Draconids produced “meteor storms” where shooting stars were produced at rates of 10,000 per hour or even more.
That’s the good news. The bad news is that the peak of the shower typically lasts only one hour, and the narrow peak of the Draconids will come this year during daylight for us in North America – between 1 and 2 p.m. EDT – in other words, nearly high noon for us in the Midwest. Making matters worse, once it gets dark, a brilliant waxing gibbous moon on the nights of this shower will interfere with the show. Nevertheless, you might try viewing it on the evenings of October 7 and 8 to see if the outburst occurs a bit off its predicted schedule.
The full moon occurs on 10/11. It will be the year’s most distant and thus smallest full moon, and will rise north of east for the first time since February.
Fall Colors – Still Not Quite at Peak
Autumn leaf change is moving quickly now, but is much less than peak as of this writing (9/26). Still, there are splashes of color everywhere that just dazzle the eyes, with the promise of even more to come. It’s a time of year that truly is enlivening, with the crisp air, lack of insects, and winds that carry the dry sounds of leaves whisking along the ground. Everything just seems sharper, more poignant. Tom Anderson in his fine book Learning Nature by a Country Road wrote, “I don’t believe there is a wind that has more responsibilities than one conceived in autumn . . . It is in the fall that the winds most need to hurry and get their jobs done. The passengers on these winds are many. Sailing away are summer’s dreams, while winter’s promise rides the same wind.”
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