Jim Williams has been watching birds and writing about their antics since before "Gilligan's Island" went into reruns. Join him for his unique insights, his everyday adventures and an open conversation about the birds in your back yard and beyond.
A friend wrote to tell me that she had covered the perches of her bird feeders with material to keep birds’ feet from contact with cold metal. She has a kind heart. Actually, birds have adaptations to foot muscles, nerves, and blood supply that make damage from cold weather unlikely. While looking for information on this in Cornell Lab’s “Handbook of Bird Biology,” I learned that some birds have fingerprints. The feet of birds like raptors and parrots have papillae, small, nipple-like projections that cover the bottom of the foot. They form patterns that vary from individual to individual, allowing birds of similar appearance to be identified one from another. This is said to be handy in particular for identifying birds of significant value, birds stolen for instance. I wonder if you can scan bird eyes for the same pupil differences used to identify humans. Probably. Generally speaking, at this point in human development we can do way more than we need to do.
Migration of birds of all species north and south is very different than it was a decade or two ago. That's well-documented for waterfowl in particular in a story in the most recent edition of the magazine Delta Waterfowl sends to members.
The story reports results of study of hunting statistics for the past 25 years.
“What we found,” said Dr. Frank Rohwer, president of Delta Waterfowl, “was a phenomenal later shift in the harvest of migrating ducks in the mid-latitude and southern states.”
The information indicates that the birds are migrating later, although Dr. Rohwer did not come right out and say so.
He used Kansas as an example. Average harvest date for Mallards in 1961 was Nov. 7. That date shifted to Dec. 5, 28 days later, in 2008-2009. For duck species resident in those southern hunting areas, birds that would not be migrating, harvest-date patterns were unchanged.
Ducks are staying later into the fall and winter seasons in North and South Dakota, which is why harvest dates to the south are becoming later. In January 2012 a record number of ducks and geese were counted in North Dakota. The article said that lack of snow cover was the primary reason the birds had not moved south.
In South Dakota a similar situation was seen. Nearly a million birds were found during a January 2013 survey.
“Those midwinter numbers and the motivation for waterfowl to migrate south are driven by the amount of snow cover, open water, and periods of cold temperatures,” Dr. Rohwer was quoted as saying.
Is it that climate no longer pushes the ducks south at historic dates? Or, for southern hunters, is it that the ducks don’t get down to them, not having to go as far south to find open water and food (which is climate-related).
The question: Is it climate change or habitat change? Biologists believe it is both.
At Sand Lake National Wildlife Refuge in northeastern South Dakota later migration of geese is more obvious than such for ducks. That information comes from refuge biologist William Schultze.
“Since I began working here in 1976,” he wrote in an email, “the average peak of the Snow Goose migration has shifted from late October to near mid-November.
“I see changes in agricultural practices in North Dakota and Canada as the primary reason for that shift,” he said. “One other factor that might be considered is the amount of wetlands available, at least in northern South Dakota, since the mid-1990s. The larger wetlands that remain open longer can hold a lot of ducks and geese,” he said.
Goose movement was heavy after Nov. 21 at Sand Lake, the date refuge lakes froze over. The number of Snow Geese reported on the refuge on Nov. 20 was 130,000, with 125,000 ducks and 5,000 geese estimated. Five days later the number of Snow Geese was 400, Canada Geese 3,500, ducks 18,000, and swans zero.
This photo of Snow Geese was taken at Sand Lake NWR.
The chimney that provided me with a Chimney Swift nest last year has done so again. A friend helped me Wednesday morning take photos of and then remove the nest from the chimney. That involved some gentle pry work with a spatula. These birds have adhered their nests to the brick surface just above the fireplace floor and just below the metal chimney liner. A rough surface is needed for nest placement. The birds’ saliva is the glue that holds the nest in place and together. The nest sat about 10 feet down from the chimney opening and two feet above the fireplace floor. It was easily reachable. The chimney lining is evident in the photo. We’re looking at the nest from the bottom. What appears as the bottom edge of the nest in the photo is actually the front lip of the nest. The nest was surprisingly shallow, and had a slight downhill slant. The nest projected three inches from the brick, and is four inches across. The cup that held the young birds — normally four in number — has a diameter of about two inches. That’s pretty cozy. This nest held some egg shell pieces. There was no evidence on the fireplace floor of birds ever using the chimney. Young swifts produce their waste in fecal sacs that are removed by the adult birds. The birds, their sounds first mistaken for bats, could easily be heard while the nest was active. The swifts have returned to this chimney for several years without a miss.
Birds of Paradise -- incredibly beautiful and strangely behaving birds found in New Guinea and surrounding islands. Video of these birds is always worth a look. The Cornell Lab of Ornithology and National Geographic are working on a project that has produced some amazing video footage. You can watch it at https://www.youtube.com/embed/REP4S0uqEOc.
When you are finished with this video go to http://www.youtube.com/watch?v=dcGPF2gTRrA for a brief discussion of avian DNA prepared by the Bell Museum of Natural History at the University of Minnesota. It features Dr. Robert Zink, professor of biology and a world expert in bird diversity and how we study it.
Scary thought: by the end of this century or close to it, far northern Minnesota could resemble from a vegetative standpoint our Orono neighborhood, in particular our yard. This would be the undesired result of a warming climate.
I learned that when reading the excellent article on forests of the future in the StarTribune of Sunday, Oct. 20. The article focused on our boreal forest, the forest you see in the Boundary Waters Canoe Area.
An illustration with the article showed “A possible 2100 BWCA Landscape.” The plants depicted were:
* Little blue stem, a prairie grass that isn’t on our yard but grows about a mile north of us.
* Prickly-pear cactus. We have it in our flowerbeds, imported from Nebraska and South Dakota, and thriving.
* Red oak and burr oak. Not in our yard but close.
*Basswood. We have it.
* Hackberry. We have it.
* Hybrid cattail. We have that, too.
* The only plant I'm not certain of is juniper, although it could be nearby and unnoticed.
That vegetative change, of course, would produce a profound change in bird life as well. Many species would disappear from the state, moving north with the climate and vegetative change.
Minnesota is home in the breeding season to about 20 species of warblers. Several of them depend upon spruce trees, which would be among the plant species considered non-survivors.
Birds are very good at finding specific niches in which they find food. In a single spruce tree you could find five species of warbler making a living, each staking out a particular part of the tree.
Yellow-rumped Warblers feed mostly in the tree’s understory, below 10 feet. The Black-throated Green Warbler works the mid-portion of the tree. It shares these branches with Cape May Warblers. They can share because Black-throated Green hunts on the branches, while Cape May looks for insects attracted by sap on the trunk.
Blackburnian Warblers and Bay-breasted Warblers share the treetops. The former feeds on outer branches and by fly-catching aerial insects, while the latter finds insects closer to the trunk.
You can see what happens to bird diversity as spruce trees fade to cooler climes.
Read the article. Consider our future. Do something about it.
(The information on warblers and spruce trees was taken from the book “How Not to Be Eaten By Insects,” author Gilbert Waldbauer, newly released by University of California Press.)
Below, Black-throated Green Warbler
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