A cool thing happened in January when I least expected it. While walking from the Glen Ellyn YMCA to the Walgreens next door, I noticed that the neighboring water detention area was full of ducks.
All mallards was my first impression, and they were clearly enjoying the open water on this unusually warm winter morning. I paused for a moment to count them and realized there was an impostor. Mixing with the four dozen greenheads was a single American black duck.
Black ducks are not uncommon in DuPage, but they are not everyday birds either. It was a pleasant surprise to see one so close when just going about my usual routine.
Experienced birders know to expect the unexpected, and that's a smart way to approach the hobby if you want to see new birds. There might be an uncommon species, or even a mega-rarity in our midst, but it takes a careful and patient observer to detect it.
Spotting the black duck was easy. The temporary pond was tiny so the birds were in close quarters. And while blackies are closely related to mallards, they are not hard to tell apart. With other waterfowl, that's not always the case.
Some birders like to examine massive flocks of foraging Canada geese in hopes of finding a cackling goose. I seldom have the patience for this activity, but I admire those who do. One such person is my friend Don from Wheaton, who once pointed out a cackler during a Christmas Bird Count at Cantigny.
We were on the golf course and trying to estimate how many Canada geese were grazing on the turf. Don then noticed that one of the birds was notably smaller, with a short neck and stubby little bill. Sure enough, it was a cackling goose -- a Canada goose look-alike. It was a new species for my life list and I'm quite sure I'd never have found it on my own.
On the topic of geese, you might have heard about the barnacle goose that turned up in Yorkville last fall. That too was a case of somebody being observant and not assuming a goose flock was "all Canada." The barnacle was a life bird for many who chased after it once the discovery was reported on the Internet.
If a barnacle goose or a cackling goose is flying with a flock of Canada geese, it likely would go unnoticed. Still, passing V formations of geese are worth a scan.
Occasionally you might notice one goose that is white with black wingtips. What you have then is a snow goose -- or possibly even a Ross's goose, since they look alike from afar.
Flocks of sandhill cranes should be checked carefully, too. Whooping cranes sometimes travel with the sandies and are easy to pick out because they, too, are white with black wingtips. A few whoopers were witnessed in DuPage last fall.
More than a decade ago, I drove to Jasper-Pulaski Wildlife Area in Indiana to see a vagrant common crane -- a Eurasian species that rarely visits the United States. The gray bird was mingling with hundreds of sandhill cranes (also gray) way out in a field of corn stubble. That anybody spotted that bird in the first place was a miracle.
Excited birders reported a couple other "needle in a haystack" stories recently at Chicago Botanic Garden in Glencoe. In both cases, the birds involved were far smaller than ducks, geese or cranes.
The site is well-known as perhaps the most reliable place in this region to find common redpolls, a coveted winter finch that favors the birch trees outside the garden's Regenstein Center. In January, a locally rare hoary redpoll was found mixing with the flock.
I have never seen a hoary. In fact, one could land on my shoe and I'd probably still call it a common. The two species are virtually identical, making this one of the tougher identification challenges in birding.
Birders with far greater skills than I located, confirmed and photographed the female hoary redpoll last month. This is worth remembering in case you make a run up to Glencoe. And if you only find common redpolls it will be well worth the trip. (They too are hardly "common" around here.)
Another rare winter visitor to watch for at Chicago Botanic Garden is Bohemian waxwing. Like redpolls, cranes and geese, waxwings are usually seen in flocks. In this region, that means cedar waxwings, one of our more beautiful local birds.
But every so often a sharp birder will notice that one of the cedars looks a little too chunky. That's the first clue that it might be something special. Bohemians are also grayer overall than cedars and sport a dark-orange patch under the tail. The undertail coverts on a cedar waxwing are white.
The lesson here is that closely related species often spend time together. When you encounter a group of birds that appears to be of one species, never assume that is the case. Take a few minutes to scan the flock. With luck and patience, you might be rewarded.
• Jeff Reiter's column appears monthly in the Daily Herald. You can reach him via his blog, Words on Birds.