A bird’s blessing

The American Goldfinch is a patient bird, at least when it comes to building a home and raising a family.

Each season, goldfinches are among the last of our birds to establish nests. Most others already have fledglings – you can hear them now, squeaking and whining at their parents to feed them. But goldfinches are just getting their nest work underway.

Why? The goldfinch seems to time its domestic duties to the season of the thistles, those prickly wildflowers most people hate. Early thistles are just now going to seed, producing the super-soft down that is so opposite the thorns that bedeck the plants. Goldfinches love thistle down as a material for lining their nests.

After the eggs have hatched, thistles provide their second benefit: Food. Goldfinches are mostly seed-eaters and they delay raising a family – with a bunch of hungry mouths to feed – until mid-summer when the season of seeds is well underway. Probably their favorite seed is the thistle.

“Cursed is the ground because of you,” God told Adam in the Garden of Eden. “Thorns and thistles it shall bring forth for you.” Clearly, a man’s curse can be a bird’s blessing.

Sound of the Veery

I heard a Veery on Sunday. That may not sound like a big deal, but it’s the first one I’ve heard locally in more than five years.

And hearing them is often all you do, for these brown thrushes are somewhat secretive and stick to woodlands where they can be hard to spot.

However, their song is one of the most distinctive and easy to recognize of any of our migrants. It’s a flutelike cascade of notes, seeming to echo as if they were sung through a long open pipe. Once you’ve heard the song, you never forget it.

Time was when the song of the Veery was a sure sign that spring had settled in. It was something to listen for. But Veeries are in what the Cornell Lab of Ornithology calls a “slow decline” throughout their range.

In winter, that range includes a large area of central and northern South America, much of it rain forest, which, as we all know by now, is being cut down. Ornithologists suspect that this “rapid habitat conversion” is reducing the Veery population.

Up north, these birds may also be suffering from the deer overpopulation. Veeries nest on or near the ground and thus prefer woods with dense understory that provides a degree of camouflage and protection. Overpopulating deer have stripped so much of the understory of our woods that Veeries may be having difficulty finding suitable nesting sites. (However, the latest statistics from the state of Connecticut indicate the state’s deer population may be in decline from a peak of 75,000 a few years ago to a current estimate of 62,000.)

Veeries have also suffered from nest parasitism by Brown-headed Cowbirds, but the latest studies on cowbirds are finding that these birds may also in decline. So it’s likely that the habitat destruction, in both winter and summer ranges, have been affecting the Veery numbers in our neighborhood.

Are deer down?

Connecticut’ deer population has been stabilizing, maybe even declining. So says the Wildlife Division of the Connecticut Department of Environmental, which in February completed its latest aerial population survey.

Officials put many qualifiers on their numbers, including the fact that the aerial survey looks at only one percent of the state’s total deer habitat. Nonetheless, from 1993 to 2003, the estimated winter deer population rose from 49,472 to 75,771. Last winter, the estimate was 62,163. If the state’s system of surveying is reasonably accurate, that would be a noteworthy decline.

We are still in the most deer dense part of the state. Fairfield County has an estimated 29.4 deer per square mile, the highest density of any of the 12 state zones. The statewide average is 17.

Wildlife officials also watch data on hunter kills, deer-vehicle collisions, and even “homeowner concerns,” and all also seem to indicate the population is at least stabilizing.

Why? The state has “adjusted deer seasons, modified bag limits, and encouraged the harvest of antlerless deer in high deer density areas,” DEP said. “Wise deer management results in healthy deer populations and productive wildlife habitat.”

In a word, the state seems to be saying, hunting.

The Big Stink

There’s been a big stink at the University of Connecticut lately. No, it’s not some scandal or controversy, but the blooming of a Titan Arum – two, in fact – at a university greenhouse. Only twice since the 1930s has this species flowered in the Northeast, and UConn has two in one season.

Natives of Sumatra, Titan Arums bear huge blooms that literally reek. Both in their foul odor and reddish color, the flowers mimic carrion, all in an effort to draw flesh-eating flies to pollinate them.

However, you don’t have to go to UConn or Sumatra to see the same technique in action in our own woods. Early each spring, our wetlands are bursting with Skunk Cabbage flowers, another Arum that uses exactly the same technique – carrion color and scent – to attract flies.

Still another spring stinker is Purple Trillium, a fly-baiter that may qualify as the worst-smelling wildflower in North America. But its odor is not a defense and unlike an Arum, the trillium is not bitter-tasting. Unfortunately, hungry deer won’t turn their noses up at a bad smell, and have been eating our trilliums into oblivion.

Nest success

This is the time of year when birds are building and using nests. But as parents, birds are often unsuccessful, both at building nests and at protecting their occupants.

Bad weather and faulty construction can lead to nest failure. But most bird nests are also subject to predators. Various studies of nest predation have found that between a third and a half of nests are attacked by other birds, small mammals, and reptiles such as snakes.

Percentages of predation can vary widely. A study of Hermit Thrushes in Arizona found that predators attacked 83% of the nests. A study in the same state of Black-headed Grosbeaks found predators attacked only 23% of the nests.

Dr. Steven W. Kress reported a study that found that of 100 Song Sparrow eggs, 74 hatched successfully and 52 eventually fledged. That’s a loss of nearly 50%.

Years ago, Dr. Arthur Allen of Cornell University estimated that less than 20% of all nests succeed in producing a complete set of new, mature birds. But as Allan and Helen Cruickshank point out, that’s nature’s checks and balances. “Should all of the birds’ eggs laid in North America in a single season not only hatch but the young mature,” they said, “the continent itself would be so crowded with birds that man himself would suffer acutely.”

Frozen out

Tulip Trees bloom in May – you can see their petals being discarded to the ground below by squirrels eating parts of the sweet, green-orange flowers. These members of the magnolia family are our tallest trees, averaging 120 feet, often reaching 150 feet, and known as tall as 190 feet.

Tulip Trees were once circumboreal – found in North America, Europe and Asia. They now live only in China and eastern North America. The European Tulip Trees were wiped out, not by man but nature, in the last ice age. On our continent, as the ice moved south, the Tulip Tree seeded its way southward ahead of the shelf. In Europe, however, the Mediterranean to the south and mountains to the east trapped the species and none survived.

Because our trees could “escape” down the north-south coastal plains, ridges and valleys, our part of the world is home to many more species than Europe has.

Alien invasion

A new invasion of alien plants is looming, but the invaders are not from the east or west, but the south.

For centuries, aliens have been arriving from Europe and Asia, imported as garden flowers, herbal flavorings or medicines, or just hitching a ride with crop seeds. They came from climates similar to ours and, finding no enemies, the likes of Garlic Mustard, Purple Loosestrife, Japanese Knotweed, and Japanese Barberry thrived to become pests.

Enter global warming. As the New England winters weaken, both plants and animals that could not survive here are moving northward. While white birches and other species are dying off because of the warmth, palms are already surviving in southern New Jersey and Pennsylvania, and kudzu, which has been called “the plant that ate the South,” has crossed the Mason-Dixon and is already in Connecticut.

How to deal with so complex a problem befuddles even the experts, but it can’t hurt for us to leave a smaller footprint on our Earth, while at the same time, stomping invasives when we spot them.