Cities gone wild

But hugely, by island’s end, the amusements were those of a remote wildlife refuge. Barnacle geese marched across rolling grasses. Swans drifted down a narrow canal separating Djurgarden from the main island. Large woodpeckers rattled the trees. At my feet, clusters of red beetle-like insects darted in and around last fall’s humus.

The herons drowned out all else. It was last April and they were frenetic in gangly flight. Like our great blue heron of North America, their wingspans, beaks, and crests evoke pterodactyls. They went back and forth with twigs and reeds to build nests in the tops of trees, making loud croaking noises as they sought to balance on the branches.

Most blue heron rookeries in the United States are built a significant distance from human interference. These herons constructed cribs and cavorted with mates as people jogged with their dogs and bicyclists breezed past. My great pocket tour book on walking in the Swedish capital said, “April means still-lifeless parks.’’

If this is lifeless, then death may not be that bad.

A week later in Copenhagen, I saw another grey heron rookery. This one was right in the middle of the city, on a tiny island in Frederiksberg Have, a square half-mile of park so thickly wooded with majestic old trees that my pocket guide called it the Danish capital’s “most romantic park.’’

The romance was aplenty of the avian kind. There was the same squawking and flying about for nest twigs. But this was even more intimate because this was a more urban park than the giant Djurgarden. There were two subway stops, each just six blocks away. In the States, our great blue heron tends to spook very easily from many yards away, unless it is wading in places where it feels comfortable, such as the Everglades.

Frederiksberg Have was Everglades north. Grey herons flew down from their nest and perched on branches right above my head. One dropped down by a park bench and hung out with mallards for several minutes. Another floated down to a walking-bridge railing I had just crossed and stayed as still as a sentinel while a misty rain draped over the park.

Two weeks of this left me floating and misty-eyed.

Copenhagen and Stockholm were ranked first and second, respectively, of 30 cities in the 2009 European Green Cities Index, compiled by the Economist magazine and Siemens, the global engineering conglomerate.

The rankings are derived from markers such as public transportation, air and water quality, waste removal, energy efficiency in buildings, and land use. Among the features of both cities that have reached iconic status are their networks of bicycle lanes that are next to sidewalks and segregated from motor vehicles. Last year, the International Cycling Union declared Copenhagen to be the world’s best biking city for its 242 miles of bike paths. Stockholm, with 472 miles of lanes, was the European Commission’s Green Capital of 2010.

These routes are a big reason that 68 percent of Copenhagen residents walk, bicycle, or take public transport to work or school. Walking and cycling alone comprise 68 percent of Stockholm commutes. The Economist and Siemens call that “astonishing’’ because Stockholm has the second-lowest average temperature of the 30 major European cities that comprise their index. Many a travel article has mentioned the wonders of cycling in these cities and others, such as Amsterdam. For those who have the time to tour by foot, the benefits grow richer still.

It is in the heron and other creatures that the full quality of urban life is revealed. The wideness of the combined sidewalks and cycle tracks nudges automobiles far enough away to allow the natural world to feel comfortable in ways barely imaginable in many US cities. (The recreational path around the Charles River in Boston is one resource that comes close, with herons, ducklings, and goslings lining the shore in springtime.)

Something you rarely see in the States virtually at your feet is a swan’s nest. That is precisely what I encountered on a jog in Copenhagen on a combined bike and pedestrian path that ringed a strip of shallow lakes in the middle of the city.

The nest was in a mini-marsh no more than 20 feet from the edge of the path. The swan on the nest stood up to reveal one egg. I was so excited that I brought my wife, Michelle Holmes, back to show it to her. When the swan got up to move around, it revealed two eggs.

We watched for an hour as the male and female switched spots on the nest, taking turns incubating the eggs. The water was full of other waterfowl, including tufted ducks and beautiful great crested grebes that occasionally flashed an orange and black mane. Sometimes the swans just stared back at the many walkers and bicyclists that stopped to admire the sight. A woman who lived nearby came for her daily inspection of the nest and told me that the year before, the swans had produced seven eggs in that same spot. An average clutch is five or six.

If that is not enough to persuade one of the health of this urban environment, this might: The mute swan, the subject of “The Ugly Duckling’’ by Hans Christian Andersen, was declared Denmark’s national bird in 1984, and the oldest-known mute swan in the world died in 2008 in Denmark at 40. The oldest before that had died in Sweden at 28. Breeding populations were nearly driven into extinction in the 1920s. The bird was given legal protection in 1926 and has recovered to the point where there are a reported 4,500 breeding pairs in Denmark today.

When Danish scientists described the 40-year-old swan as “a well-nourished bird in very good health,’’ they might have been talking about the bird’s environs as well.

In Stockholm’s Djurgarden, a barnacle goose waddled around grounds of one of the villas perforated with blue, yellow, and white ground flowers. Even before Michelle and I walked into the woodland of Haga Park, 2 miles north of downtown, an adjacent cemetery beckoned me with an iris-like flower the height of a crocus that I had never seen before, white with green and yellow tinges. The grounds of the Karolinska Institute, where the Nobel Prize in medicine is decided every year, were awash in blue flowers.

A week later and 325 miles to the south, a long strip in the Kongens Have royal gardens, established in the early 1600s, was a wall of purple, white, and purple-white crocus. Two blocks away, Copenhagen’s botanical garden, established in 1874 and the fourth of a series of gardens that began in 1600, was full of blue ground cover in grassy areas and red tulips in a rocky garden.

At Frederiksberg Have, the grounds were so mesmerizing, I visited three times, two walking and one jogging. On the first walking day, a magpie, a black-and-white, crow-shaped bird with a long tail and shimmering blue off the wings, bounded about in the sun among waves of purple, white, and golden crocus. Mallards were nestled, their green heads shimmering among blue ground flowers.

On the second day, the sun and the crocus were gone, replaced by a cold mist that eventually became sleet and snow flurries. But a whole other crop of light and dark blue ground flowers had popped up, in thick carpets around the base of thick, old trees. Where up in Stockholm the waddlers among the flowers were barnacle geese, here ambling about were a pair of greylag geese, which are more gray-brown. As they periodically sat in the flowered grass, their dull colors with the dull light nearly turned the blue flowers into thousands of blue lamps.

As the rain and snow became heavier under darkening skies, to the point where I was clearly the last person left in a park, I could see a white spot in the distance. It was on the same island where the herons roost. I walked toward it. As I came over a bridge, I could look down and see that it was one more mute swan, sitting on its nest.

Derrick Z. Jackson can be reached at jackson@globe.com.