Birders urge city to keep ramp during I Street Bridge rebuild to protect a rare bird

Dan Airola has been studying birds in Sacramento for more than 30 years.

The wildlife biologist meticulously keeps track of how many purple martins — the largest swallow in North America — are nesting in the city year after year. That’s how he knows there are only 29 nesting pairs left in the city, compared to 173 in 2004, and that they only nest in six places.

One of those spots is in jeopardy. The city plans to demolish a nesting spot behind the California State Railroad Museum when it rebuilds the I Street Bridge over the Sacramento River.

Purple martins have been nesting underneath the ramp that connects the I Street Bridge to J Street since at least 1971, according to Airola’s records.

Airola and a group of birders from California, Oregon, Colorado and British Columbia are urging city officials to leave a portion of the ramp in place to leave the birds undisturbed.

The city is planning to demolish the ramp for several reasons, said Jesse Gothan, supervising engineer.

Caltrans will fund the majority of the new $172 million bridge, planned to be built upstream from the current spot, but only if the city decommissions the old bridge to auto traffic, including the ramp, Gothan said.

Also, city officials worry if the ramp is left in place, it could become a nuisance, with people congregating on top of the ramp and graffiti popping up. City workers would also face a challenge in accessing the ramp for maintenance, he said.

“We don’t really see the purpose of leaving that large of a structure in place,” Gothan said.

The city is working on a mitigation plan for the birds, but that will be difficult, Airola said.

The Sacramento Audubon Society placed five nesting boxes underneath the overpass for 10 years, to see if the birds would nest there instead. None did, Airola said.

“The fact is, as they’ve declined, this is where they want to be,” Airola said.

Research suggests the bird’s declining population is linked to the use of neonicotinoids, a common type of insecticide.

If the pesticide is not banned, Airola’s research suggests the purple martin population will go extinct in 20 to 25 years.

“We’re trying to get the city to maintain the bridge for 25 years to allow the population to exist until either the pesticide problem is solved, or the birds no longer exist,” Airola said.

West Sacramento officials are considering repurposing the upper deck of the existing bridge for bicycles and pedestrians, but if that happens, the ramp where the birds nest would still need to come down, Gothan said.

The city does not plan to demolish the ramp until after the new bridge is open, which is planned for 2022, Gothan said.

Gothan and city officials are continuously working with the bird advocates on the best solution in terms of nesting, said Marycon Young, a city spokeswoman.

“It is our hope that we could observe the purple martins successfully move,” Gothan said.