A Northwoods Almanac for February 25 – March 10, 2011
by John Bates
Sharp-shinned Hawks
Jody Loeffler on Anvil Lake recently reported finding a male sharp-shinned hawk dead in her yard. Shortly thereafter, she noticed another sharp-shinned perched in a tree above where she found the first hawk, and she wondered if it might be the mate of the one she found dead.
Never say never, but I’d be surprised if they were a mated pair given that sharpies usually migrate alone (66% of 271 migrants in a study in Central Park, New York City) or in small groups of several individuals that often include broad-winged hawks, red-tailed hawks, and American kestrels.
The literature on sharpies says they are presumed to be monogamous, but there are no studies that actually document this, and there is no information on the duration of their pair bond. While researchers have noted that their nesting territories are frequently reused, the identity of the pair members has never been ascertained. Thus, surprisingly, there’s no study I can find that would indicate whether or not sharp-shinneds overwinter with their mates.
Jody’s sighting of the sharpies is interesting in that sharpies are not considered “usual” over-winterers in northern Wisconsin. Occasionally we have counted one during our Christmas bird counts, and rarely have people called me in the winter with sightings of a sharpie hunting their bird feeders.
Sharpies are only about the size of a blue jay, but they are also the most sexually dimorphic of all North American raptors, with males averaging only 57% of the body mass of females. So, differentiating a large female sharpie from a small male Cooper’s hawk, which look almost identical, can be really tricky.
Their small size helps make both genders masters at capturing songbirds. Numerous studies show that songbirds consistently represent 90% of their prey items. Sharpies are particularly well known for hunting songbirds in parks and near houses, and they’re often seen taking prey at bird feeders. Thus, they’re a mixed blessing to see at this time of the year, because their presence means an ever-diminishing number of songbirds will be appearing at your feeders.
Plasticity
Mary and I have recently noticed some gravity-defying snow hanging far below the tree branches it is attached to. Snow does some amazing balancing tricks, shaping itself around branches, roof eaves, and other surfaces with an apparent disdain for ordinary physics. Snow can actually flow around objects without breaking, behaving a bit like water in very slow motion.
This process, called plasticity, provides benefits for small mammals living under the snow. As snow flows off a boulder or downed tree trunk, it eventually reaches the ground a short distance away, creating a hollow or tunnel on either side of the object. Within the tunnel, mice, voles, and shrews, and some wintering insects can move freely and easily alongside the tree or boulder, while being insulated and protected from the outside world.
Sightings – Evening Grosbeaks
Al and Pam Eschenbauch in Presque Isle report having a “herd” of four dozen evening grosbeaks at their feeders, an increase from the two to three dozen they have had off and on at their feeders since late December. In previous years, Al notes that they have also had 4 to 5 dozen of the “brazen, feathered pigs” all winter.
Al and Pam’s experience is quite uncommon these days – very few people are reporting any evening grosbeaks at their feeders, much less several dozen. A decade ago, they were very common, and many of us also referred to them as “feathered pigs” for their prodigious appetites at our feeders. Not any more. Most of us would be absolutely delighted to be buying far more seed if the evening grosbeaks would just return to our feeders.
Mary Madsen on Twin Island Lake in Presque Isle noted in an e-mail that “this is the first winter we can remember that we have not had evening grosbeaks. Happily, today [2/20] a "pair" showed up at the feeder.”
Sightings – Cardinals
Mary Madson in Presque Isle also noted, “I can't believe that our cardinal has been a regular at the feeder all winter. I use to think I was lucky to see one every few years.”
In Manitowish, we have had a female cardinal visiting our feeders all winter as well.
Sightings – Pine Grosbeaks
Glen Esswein in Woodruff reported: “Over the last two weeks, we have had a flock of about 20 to 25 pine grosbeaks in our flowering crab tree. They are all females – no males have shown up. They share the fruits with a flock of cedar waxwings.”
In Manitowish, Mary and I still are lucky enough to have about 18 pine grosbeaks, a mixed flock of males/females/juveniles, grace our feeders every morning.
Miscellaneous – Barred Owl, Hairy Woodpecker, Badger
Bob and Chris Frenz sent me several photos of a barred owl that was sitting one morning on a branch above their bird feeder in St. Germain.
David Lintereur in Lake Tomahawk watched a hairy woodpecker pecking at a deer carcass. He said it was standing on the ribs, and there was still quite a bit of meat left. I noted in my e-mail response that the woodpecker was almost certainly eating the fat that was on the carcass and that many bird species, including chickadees and nuthatches, gladly utilize high energy fat to help them get through a long winter.
John Granger called me to say that over many years he has seen several badgers near Two Sisters Lake in McNaughton, and he didn’t realize they were rare! John’s sightings make me envious – I’ve still never seen a badger up here, though I’ve seen their holes many, many times.
Celestial Events
As of 2/27, we’re up to 11 hours of daylight, and by 3/8, we’ll receive 11 ½ hours of daylight. Spring equinox is coming up!
Before dawn on 2/28, look for Venus just one degree south of the waning crescent moon.
The new moon occurs on 3/4.
We reach a milestone on 3/6 – our average high temperature finally reaches 32°F.
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