NWA 1/20/12

A Northwoods Almanac for January 20 – February 2, 2012

Ice-up on the Manitowish River

            In the 28 years we’ve lived on the Manitowish River, we’ve not seen the river remain open as late as it has this year. It finally iced up at our home on 1/3, but barely. Open water into January likely pleases semi-aquatic mammals like otters, beavers, and muskrats, and fish eating birds like bald eagles, but I’m not sure I see late ice-up in our area altering the behavior of most wildlife species.

            However, the lack of ice this winter on the Mississippi River has altered the wintering pattern of bald eagles. The National Eagle Center in Wabasha, MN, does a weekly winter count at several sites in WI, and their count numbers are very low for this time of the year. With the mild weather, there’s both plenty of open water and no snow cover, so the eagles are roaming the snow-free countryside looking for food. Normally the dams along the Mississippi offer some of the only open water available to the eagles, and so concentrate the eagles there. But not this year.

The serious downside to the widely foraging bald eagles is that they are finding deer gut piles and unrecovered deer from the hunting season that would ordinarily be hidden under the snow. Inside the deer are very small fragments of lead bullets, which if eaten by an eagle can be enough to kill them. The Center had four bald eagles brought in during December, and three of them had to be euthanized because of high lead levels. The other one is still being treated for lead at The Raptor Center at the University of Minnesota.

The PBS nature film “American Eagle” photographed by Wisconsinite Neil Rettig, has a video sequence of a bald eagle dyeing from lead poisoning, which can be seen online at www.pbs.org/wnet/nature/episodes/american-eagle/video-full-episode/4349/

A bit closer to home, in the first week of January an unprecedented amount of open water on Chequamegon Bay produced another behavioral change in some waterfowl, inducing the following individuals to linger:

2 tundra swans (extremely rare January record)

275 common goldeneyes

39 common mergansers

9 red-breasted mergansers

2 greater scaup (very rare January record)

1 lesser scaup (extremely rare January record)

1 bufflehead (rare January record)

Sightings

            Cheryl Crawford in Harshaw reported that a ruby-crowned kinglet continues to eat from her suet feeders and a feeder containing crushed peanuts. Ruby-crowneds winter well south of there, typically into Tennessee and Arkansas and south into Central America, so its presence is very unusual. Occasionally an individual is reported on a Christmas bird count in southern Wisconsin, but we’ve never seen one in the 19 years of our count in Manitowish Waters. We rarely get golden-crowned kinglets, but not ruby-crowned kinglets.

Neil Long, a long-time resident of Sayner and a highly respected outdoorsman, reported a sharp-tailed grouse walking by his feeders and apparently taking corn from neighboring feeders. I’ve never heard of a sharp-tailed grouse coming to a feeder in our area, so I’m really surprised and delighted to hear of one. Sharp-taileds are a species of brush prairies and wide-open spaces, certainly not a habitat characteristic of the Sayner area. In our area, I’m only aware of a tiny flock that lives in the huge Powell Marsh, and a flock that lives in the Riley Wildlife Area south of Hwy. 70 between Minocqua and Fifield.

Pat Schwai reported her good fortune in hosting a small flock of 10 to 15 redpolls in her yard each day so far in 2012. Redpolls are relatively scarce in our area this winter, so Pat is indeed lucky.

Dave and Suzy Foster also have had small groups of common redpolls at their feeders daily in Natural Lakes since December 16. However, they’ve also had groups of up to 30 evening grosbeaks almost every day since December 24, making pigs of themselves at their feeders as evening grosbeaks are wont to do. 

On 1/3, Ed Marshall had a northern shrike show up at his feeders. As Ed noted, the songbird-eating shrike “was not popular; all the other birds left for safer territory.”
Shrikes are very uncommon this winter –Mary and I are still hoping to see our first of the year.

Wil Conway sent me some fine photos of a coyote that he took through the glass doors at his home on Fence Lake. The coyote was adept at using cover to hide his presence, but Wil caught him easily visible several times.

 A Case of Cold Feet

The juvenile summer tanager that was first seen in Arbor Vitae nearly two months ago remained in the area until 1/13, and has not been seen since as of this writing (1/16). One of the people who has fed him reported on 1/10: “Wrong-way is suffering more problems with his feet. He does a lot of fluttering to move himself around our tray feeder (vs. ambulating himself with his feet), also on branches, and in relation to drinking from our birdbath . . . It appears that he is unable to bend down from his standing position to drink. Finally, in desperation what I've seen him do both yesterday and today is attempt to drink on the fly. Yesterday his feet landed in the water a little and he immediately flew away afterwards. Today he was able to hover and take two sips without getting his feet wet. It's not known exactly what the problem is with his feet but I fear that it could become the straw that broke the camel's back and cause him to perish – especially with more cold and snow expected soon.”

One of many reasons why most birds gladly depart our area for the winter is their inability to protect their feet from freezing. Only a few birds have feathers covering their legs and feet. Ptarmigans in the far North grow extra feathers on their feet during the winter to provide insulation and to offer a larger surface for support on the snow. Most owls have feathered feet, but the feathers appear to suppress flight sounds that might alert prey and not to provide warmth.

Thus the birds wintering in the North have had to come up with another way to prevent tissue damage to their feet due to freezing. Their solution is a specialized system of blood flow to their feet that goes through a “heat exchanger” on the way to the feet, and then again on the way back to the heart. The heat exchanger is located just below the thigh on each leg and is made of a mesh of small vessels that can take heat from the warm arterial blood flowing to the feet and use it to warm the cold venous blood that is returning. An example of the temperature gradient looks like this: the blood heading down to the feet enters the heat exchanger at 95° and by the time it circulates through the foot, the temperature has dropped to just a few degrees above freezing. The blood coming back up would shock the heart and kill the bird, so, as it goes through the heat exchanger, it is rewarmed to 91° by the 95° blood that is also circulating through the exchanger on its way down to the feet.

It’s a great system for the winter, but one that could cause problems of overheating in the summer when the birds need to cool themselves. So, on a hot summer day, the heat exchanger can be bypassed in order for the blood to be cooled as much as possible by using the feet as radiators – an ingenious solution.

Minocqua Christmas Bird Count

            The Minocqua Audubon Winter Bird Count took place on 12/29, picking up 24 species. Some surprising numbers included 19 eagles, 11 red-bellied woodpeckers, 15 pileated woodpeckers, and 60 snow buntings. Two non-native birds were tallied as well – 5 European starlings and 9 house sparrows.

Celestial Events

            It’s staying lighter longer! As of 1/27, we’ll be the recipients of 9 hours and 30 minutes of daylight, up from the 8 hours and 44 minutes we sustained around winter solstice. Our days are growing longer now by nearly 3 minutes a day.

            The new moon occurs on 1/23. On 1/30, look for Jupiter about 5 degrees south of the moon.

            Groundhog’s Day takes place on February 2. No self-respecting groundhog in the Northwoods would stick its head out on this day – they’re all in a very deep hibernation that will likely remain undisturbed into April.