The spring smelt run in Lake Michigan brings fish lovers of various biological orders to the lakefront. Around Montrose Harbor the breakwaters and step-stone revetments are covered with people bearing nets, coolers, and grills ready to catch, cook, and eat as much smelt as they can.
Flocks of fish-eating birds pick off the smelt too far out to be accessible to the shore-based humans. Most of the birds are the fish-eating ducks called mergansers–specifically red-breasted and common mergansers. The red-breasted is far more common than the common during smelt season. And there are gulls and the occasional loon. But this past spring double-crested cormorants were a noticeable part of the bird life offshore, present in much larger numbers than I had ever seen before.
When I started serious birding about 25 years ago, the double-crested cormorant was not a bird you expected to see very often in Cook County, or, for that matter, anywhere else in the state. Like other fish-eating birds, such as bald eagles and ospreys, cormorants had been heavily affected by DDT. They were laying eggs with shells too thin to survive incubation. Populations had fallen so low the bird was listed as endangered in Illinois. If you saw one cormorant you had a good birding day.
One day about two weeks ago 220 double-crested cormorants were counted at Saganashkee Slough in the Palos area. This bird is back.
The double-crested cormorant is one of 6 species of Phalacrocoracidae in North America, one of 30 species worldwide. It is the only North American species regularly found away from saltwater. Historically its breeding colonies could be found on the shores and islands of the Great Lakes, along the Illinois and Mississippi rivers, and on large inland lakes. The name comes from a pair of feather tufts that develop during breeding season and are almost always invisible to a human observer.
Cormorants have substantial patches of often brightly colored bare skin on their heads and necks. In the case of the double-crested the coloring is yellow-orange. Most of the birds I see are too far away for me to make that out. I would say that if you see an all-black, heavy-bodied, long-tailed, long-necked bird intermediate in size between a mallard and a Canada goose, you are looking at a double-crested cormorant. This guess will almost never be wrong. The only other cormorant ever seen in this area is the olivaceous cormorant, which sometimes drifts north from the Gulf of Mexico in late August and early September. Olivaceous cormorant is my all-time favorite bird name. It sounds like a character in a W.C. Fields movie.
Cormorants locate their colonies on cliff faces–if any are available–or in trees. They especially like islands or other protected sites.
They dive for their food, sometimes reaching depths of 100 feet, but usually staying in the 5-to-25-foot range. They eat all sorts of small fish, along with the occasional shrimp or water snake. The reference works usually go out of their way to insist that the birds eat nothing but commercially valueless species, but my guess is that isn’t always true. Those cormorants off Montrose in early April certainly seemed to be going after smelt.
People have been using cormorants to catch fish for centuries. Apparently training can overcome the birds’ aversion to catching commercially valuable fish. Cormorants swallow their catch whole and regurgitate the indigestible parts later. Traditionally fishing with cormorants involved fastening metal rings around their long skinny necks to keep them from swallowing what they caught. However, usually reliable sources report that well-trained, and presumably well-fed, birds will retrieve fish without rings.
If you have ever been near a nesting colony of fish-eating birds, your nose will never forget the experience. However, in the capitalist tradition of turning shit into gold, the accumulated droppings of piscivorous birds have been mined as guano, a fertilizer rich in nitrogen and phosphates. Phalacrocorax bougainvillii, a cormorant that nests on islands off the coast of Peru, has been called the most valuable bird in the world. It is the major member in a triumvirate of cormorants, boobies, and pelicans that provides the bulk of the guano deposits there.
Cormorants are unusual among diving birds in that their plumage is not waterproof. You often see them perched with their wings spread. They are drying out after a fishing trip.
The return of the double-crested cormorant began with the banning of DDT in the early 70s. At first the small population of breeding birds could produce only a small surplus. But as the breeding population grew and the amounts of DDT in the environment declined, cormorant numbers began to take off.
In 1985 the Chicago Audubon Society’s survey of the nesting birds of Cook County reported only one sighting of a cormorant during the ten-day period of the count. The following year five birds were seen, four of them possible nesters. By 1990 13 pairs were nesting at Baker’s Lake in Barrington, and birds were being seen regularly in Palos.
By 1992 28 pairs were resident at Baker’s Lake, and observers suspected more were nesting along the Sanitary & Ship Canal and the Cal-Sag Channel. The site at Baker’s Lake is an island well out from shore and therefore protected from predators. Birds that have attempted to nest at Palatine Marsh have had their nests destroyed by raccoons.
Bald eagles and Caspian terns are among the other species that have rebounded as a result of the DDT ban. However, we still have some problems. Birds in nesting colonies around Green Bay and at some other Great Lake sites show an alarming frequency of birth defects. Many young birds have crossed-bill syndrome. Their upper beaks twist to one side, and their lower beaks twist to the other; as a result they cannot close their beaks and are unable to feed themselves.
The truly diabolical part of this is that the birds can be fed by their parents. So the adults stuff food down the young bird’s gullet until it is old enough to fend for itself. Then it dies.
This problem is caused by toxic chemicals in the water–Green Bay is one of the most polluted areas in the Great Lakes, with lots of PCBs and other persistent organics. Cormorants and other fish-eating birds will not be safe until we have finished the job so nobly begun and completely eliminated toxics from the lakes.
Further notes on squirrels in Chicago. Carolyn Pulizzi was kind enough to send me a second letter–I had lost her first–about the fox squirrels that come to her back-porch feeder in the area of Diversey and Kostner. “We have two or three gray squirrels and over a dozen red ones. They are fox, as they are totally orange and quite beautiful and very friendly.”
The pictures she sent do indeed look like fox squirrels; I will pass them around to various experts for verification. This would be the third known fox squirrel population in the city.
C. Slome also writes about black squirrels in the area bounded by Western, Balmoral, Foster, and Ravenswood. Black squirrels are a color phase of the familiar gray squirrel. They are indeed totally black–or at least a charcoal gray–all over. No white on the underparts. I had asked readers to send in any information they had about where black squirrels live in the city.
Another correspondent who answered my call was Roland Flessner, who lives near Six Corners (Cicero, Irving Park, and Milwaukee) and commutes every day by bicycle to Cicero and Touhy. To pass the time he counts squirrels, and since he travels mostly on side streets to avoid the traffic, he sees lots. “Fall is by far the most active time,” he writes. “During the rest of the year, I will typically see a single- or barely double-digit number of squirrels on my ride to work. But this year, in the week before Labor Day, I saw about two dozen each direction. Last fall I noted that typical sightings would be two dozen in the morning and three dozen in the evening. The peak sighting was 62 squirrels observed on a ride home.”
Fall is generally the time when the young of the year are sent out into the world to seek their fortunes, so there is lots of movement then.
Flessner continues, “As to the black squirrels, I have frequently seen some near Six Corners, in Lincolnwood, and lately, along the North Branch Trail.”
It has been suggested that black squirrels are on the increase. The uniformly dark color could be a recessive character that is more common in some populations than in others. It could confer some disadvantage on a forest squirrel but be irrelevant to a city squirrel. Maybe black squirrels will be as common as blue-eyed Swedes.