Nesting Delta swallows are an unlikely ferry tale

It's a clunky, rusty jalopy of a boat, albeit a reliable one, with two noisy diesel engines and absolutely no sense of aesthetics, unless you're fond of peeling paint.

Some 200 times a day since 1969, the J-Mack ferry makes the same 500-foot trip across Steamboat Slough in the Delta 30 miles south of Sacramento, transporting for free and in slow motion farmers and their trucks and tractors, along with the occasional tourist.

But every spring for as long as anyone can remember, the J-Mack plays host to a miracle of nature.

By the dozens, barn swallows take mud from the waterway's banks and build nests, not much bigger than a coffee cup, that cling to the underside of the heavy steel deck and hold four or five eggs.

Frankly, it seems like a birdbrained thing to do. The J-Mack is awfully noisy. It vibrates at full power. When trucks and cars and baling machines come aboard, the boat shakes and sways. And the water is a mere two feet below the mud nests.

These barn swallows-turned-ferry swallows are such a common sight, darting and diving and swooping and circling, that passengers of the J-Mack hardly notice anymore.

Bird-watchers, however, find it a sight to behold. This time of year, the eggs should be hatching.

Elmer Aldrich, a longtime birder and naturalist, was so taken by the phenomenon during a bicycle visit to the area in 1980 that he promptly wrote about it in the Sacramento Audubon Society's newsletter. Over the years, the 93-year-old Aldrich could never forget about these birds.

He recently returned to the J-Mack for something of a swan song with the swallows. He got down on his belly on the deck and peered underneath as the ferry shuttled a lone pickup truck across the slough from Ryer Island to Grand Island. Those who work on the boat say there are usually 50 to 100 nests there.

"Nothing has changed and I think that's amazing. To me, it's an ornithological wonder that the same species of birds and the same ancient ferry are still closely associated," he said.

He said the skippers also have continued their interest in the swallows over the years.

Indeed, the J-Mack, which is owned and operated by the California Department of Transportation, is repaired and refurbished with the swallows in mind.

For instance, the ferry goes into dry dock every five years for about 30 days of painting and maintenance. But those sessions are scheduled in January when the swallows are not close to building their nests and laying their eggs, according to Robert Songey, a Caltrans manager in the Delta region.

"We're not going to disturb them," he said. "We figure the birds are gone at that time of year."

Tawfik Marmoush, one of the J-Mack's captains, said he never tires of the swallows. His favorite 12-hour shift starts at midnight. Along with sunrises and the solitude, he looks forward to seeing the swallows.

"Of course, I like them," he said with a smile as the birds flew outside the cabin. "You can hear them singing in the early morning."

Songey said he knows of no other boat that hosts so many swallows. "We have them on our drawbridges, but the bridges only open up twice a day," he said.

Why the swallows keep building their nests aboard the J-Mack is anybody's guess.

Songey likes to think it's because the ferry stirs up insects each time it crosses the slough, allowing the swallows to swoop down and gather food.

Steve Haynes, a Caltrans bridge supervisor who oversees the ferries, has often thought about it but has never come up with a good explanation.

"It's a mystery to us," he concluded.

It's possible that the swallows build their nests there simply because the birds before them and the ones before them did so, all the way back to the time the hulking J-Mack first showed up in the Delta.

"There's a big question of whether they pass on their knowledge to their young," Aldrich said.

Nothing had changed in 28 years. Not the peeling paint or the sleepy slough, and especially not all those befuddling birds.

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• Call The Bee's Blair Anthony Robertson, (916) 321-1099.