A Northwoods Almanac for April 8 – 21, 2011
Reliable Crows with Family Values
Jack Bull in Winchester has been feeding birds for many years at his home on South Turtle Lake. But he particularly enjoys feeding a crow that has been coming to his home for nearly a decade. Jack and his wife Barbara returned just two weeks ago from wintering in Florida, and within 15 minutes of Jack putting out food on his deck, the crow was back.
How does he know it’s the same crow? Well, he doesn’t – , in fact he thinks it may be one of the chicks of the original adult he began feeding years ago. But it seems clear that the crow is a family member because it landed on the deck rail, went directly to the can of food that Jack put out special for it, picked it up, and flew away as it, or a family member, has done every day for years. Somewhere, Jack suspects, there is a small landfill of catfood cans that these crows have hauled away.
Every year, Jack makes a concoction of bacon grease, bread, egg yolks, and other kitchen wastes, puts it in a shallow, wide can, and places it on his deck, thus making his home into a five-star restaurant likely noted in all the crow tourist brochures.
The original crow that first came to eat his delicacy also brought in its chicks. Jack thinks that this adult met its demise somewhere along the line, and the current visitor is one of those chicks. It would be helpful to band this fellow to be certain of its identity, but folks that feed birds don’t have that luxury. Instead, we have to try to make identifications from either small physical characteristics or specific behavioral traits.
I find Jack’s long-standing relationship with this crow family really interesting because crows have a highly unusual family structure. Crow families often are extended families with parents, offspring, and immigrants from nearby families forming a social unit throughout the year and into successive years. Some of these families even form a cooperative breeding unit with helpers that assist in raising the young of the year.
For instance, in a study of cooperatively breeding groups in Florida the cooperative groups consisted of three classes of birds: the breeding pair, yearling helpers, and adult helpers. The groups began with 7 to 9 birds but shrank as the nesting season approached to the breeding pair and 2 to 4 yearlings. The adult helpers were driven away by the breeding male while nesting, unless there were no yearlings or only one in the core group. Still, the adult helpers that were driven away stayed on the group’s territory and later came back to the nest to help feed the nestlings when the breeding male’s aggressiveness had waned.
In a study of banded crows in Encino, CA, older offspring were not driven away. In another study of cooperative groups in Stillwater, OK, the social unit had up to 12 individuals, including several adult helpers. In a study done at Cape Cod, MA, 94% of the crow groups there bred cooperatively with an average of 4.4 crows per group (ranging from 2 to 10). The groups in Massachusetts included the breeding pair and offspring over one year old, with the offspring staying on the natal territory as nonbreeding helpers for at least four years. At Encino, CA, 42 of 115 breeding pairs (37%) had auxiliaries (helpers) – of those, 32 (75%) had 1 auxiliary, 8 (20%) had 2, and 2 (5%) had 3.
Cooperative breeding also was noted in a study in Ithaca, NY, where some auxiliaries delayed breeding for up to 6 years.
With all this variability, it’s difficult to make good generalizations about the family structure of crows. Both sexes sometimes stay on the nest, and sometimes don’t; not all the auxiliaries are the offspring of the breeding pair—some move in from other families; and not all the auxiliaries help.
Helpers do things like bringing sticks to the nests, feeding the incubating and brooding females as well as feeding the nestlings, guarding the nestlings and fledglings, and helping to keep the nest clean. In one study, helpers and nonhelpers begged from, and were fed by, one or both breeders, particularly the male. Apparently one doesn’t have to work within the crow social structure to be fed.
So, what to make of Jack’s crow? Beats me. Is it carrying the food back to a cooperative breeding group? Do they have a mountain of cat-food cans beneath their nest? Don’t know. One way or another, it was very heartening to Jack to be greeted home by this crow, to know that there’s continuity in life, and to know the crow was looking forward to seeing him as much as he was looking forward to seeing it.
First Paddle of the Year
The Manitowish River has been tempting me ever since it opened up by our house on March 12th. So on 3/27, even though Mary and I had just skied in the morning and the high for the day was 27°, Bob Kovar and I dragged our kayaks across the snow to the put-in on the Manitowish, and launched the first paddle of the year. We immediately kicked up two trumpeter swans and ten Canada geese, the swans doing a low fly-by while trumpeting, an exceptional greeting to begin our paddle.
Ice hung out over the water in graceful, gravity-defying sheets, indicating how high the river had been when the ice first formed, and how comparatively low the water is now. Animal tracks were seemingly everywhere along the banks, with otter slides and prints particularly common. We came across one group of otters that Bob identified well before me – all I saw was a brown mound on the snow up ahead, but Bob saw the mound moving! The otters quickly noticed us and slipped into the water, although one hung around awhile and kept an eye on us.
Waterfowl were surprisingly few. We came upon several more flocks of geese, another pair of trumpeter swans, and a pair of common mergansers, but that was it over the course of our 1¼ hour paddle.
Perhaps most notable was how quiet it was – just the dip of the paddles, the mild wind, and our voices sharing stories from the last few months of winter. As friends do, we shared the highs and lows, the disappointments and successes, the hopes and fears, and laughed through it all. It was cold, despite our bundling up, so we paddled steadily, though the current was doing more work than we were. The most difficult moment? The pull-out when we had to get back onto shore over the protruding ice.
It was a fine first paddle, and, as always, one that helped frame our lives in the right spirit.
On, 3/19, Sue Aitken reported seeing common mergansers on the Manitowish River. On 3/22, Nancy Burns observed the return of hooded mergansers to the Manitowish.
On 3/27, John and Gale Werth reported seeing the first black duck on the Manitowish in Boulder Junction.
We’ve been gone over the last week, so we’re behind in our own sightings and in reporting other people’s sightings – we’ll catch it all up in my next column.
Loons Back in Wisconsin
As the ice comes off lakes in southern Wisconsin, birders are reporting common loons arriving, particularly on Lake Mendota and Lake Monona in Madison. The last report I saw listed 20 loons on Lake Monona on April 4.
Jennifer Heitz reported seeing a loon on March 31 on the Wisconsin River near Tomahawk, so some loons have already moved north and are utilizing open water where they can find it while they await ice-off on “their” lakes.
Websites for Loon Migration Routes and Migration on Radar
For specific information on the loons that the WDNR and USGS are tracking with the use of satellites, please go to: http://www.umesc.usgs.gov/terrestrial/migratory_birds/loons/migrations.html
As an example of the information that can be found there, Loon # 55480 is currently hanging out at Eagle Lake in SE WI (as of 4/4/11) and a number of other birds have left the Gulf of Mexico and are heading our way.
To see a great video on watching bird migrations by using weather station radar, see: http://www.youtube.com/watch?v=xhA2Kl2bwSQ
We’re gaining daylight rapidly! By 4/14, we’ll be up to nearly 13 ½ hours, with the sun rising at 6:15 a.m. and setting at 7:44 p.m.
Ice-out usually occurs for most of our lakes in mid-April. April 16 marks the 38-year average date for ice-out on Foster Lake in Hazelhurst according to Woody Hagge’s data. Once, the ice goes off, Foster lake averages 224 days of open water.
Look for the full moon ( the “Maple Sugar Moon”) on 4/17.
April 20 marks the day when our average low temperature finally reaches 32°F.
Birds of SE Arizona
Mary and I just returned late on Monday night, April 4, from a 5-day birding trip to southeastern Arizona, and we totaled 122 species! Of the many trip highlights were nine species of hummingbirds, most of which we could watch at length coming to various feeders. More on this trip next column – there are lots of birds moving our way!