A Baltimore oriole nest made of mostly horse hair, and only horse hair, is the best bird nest I have ever seen. It was found in a tree in the yard of a friend.

Alex, who showed me the nest, lives on an old farmstead, neighbor to a stable that housed a pair of horses. The hair nest was built about 100 feet from the barn, so the source of material was not in question.

I was there in a grove of trees to watch a female oriole build that spring's nest, strands of grass her material of choice.

Orioles are weavers of nests, usually working with natural fibers, vegetation of some kind, like strands of grass.

In an article in Audubon magazine a few years ago, Nancy Flood, a Thompson Rivers University biologist, describes the process well:

"You see the female poking one end of the string through, and then pulling her head back to weave it out, just like when you crochet or knit a bag.

"They can spend half an hour doing that, then go away to get another long piece of grass and do more," Flood said.

The horse-hair nest is woven tightly enough to hold water, at least for a few moments. It's a work of art. It must have taken days to build.

You often can see oriole nests hanging like trimming from tree branches. Cottonwoods are good trees to check. The nests are easier to see in the fall, of course, when they decorate naked branches.

My experiences this year have been with dove and pigeon nests. The doves were minimalists: thin curls of grass barely forming a nest in a flowerpot on an apartment balcony.

The pigeon nest also was built on a balcony, this one overlooking Loring Park. You can see in the photo taken by my friend Peter, balcony landlord, that a small plastic pot is basically all there is to the nest, an economic effort to say the least.

Birds of the pigeon family are known for flimsy platform nests. They sometimes locate nests on the window ledges of buildings. Pigeons are properly known as rock doves, cliffs being their natural nesting site.

Reader Ray Bryan of St. Paul has had house finches nesting in his garage for the past couple of years. The finch nest, with four eggs, is the antithesis of the dove nest, a tightly woven, perfectly round nest of grass. It is a work of finely tuned instinct.

Bird nests are almost as individual as birds themselves. Most of us can readily distinguish a cardinal from a chickadee, and distinguishing the nests of those two species certainly is possible once you know what to look for. Many bird nests offer that opportunity.

Minnesota has 231 confirmed nesting species of birds, according to the recently published summary of our first breeding bird survey. Some of these are year-round residents. Others are migrants here because our habitats provide them with superior nesting opportunities.

If bird nests interest you, a recommended book is "A Guide to the Nests, Eggs, and Nestlings of North American Birds," second edition, Paul J. Baicich and Colin J.O. Harrison, Academic Press, 1997.

Lifelong birder Jim Williams can be reached at woodduck38@gmail.com.