The eucalyptus trees in which herons and egrets nest, across the Petaluma River from Shollenberger Park, will be taken down by Caltrans by Feb. 15, 2013. This is in preparation for construction of the Petaluma Blvd. South interchange. Caltrans believes the nesting trees are too close to the construction area.

The Shollenberger Colony fledged 424 healthy Great Blue Herons, Great Egrets and Snowy Egrets during 2003-2012, according to data submitted to Cypress Grove Research Center (Audubon Canyon Ranch) by Petaluma Wetlands Alliance (PWA) docents.

Herons and egrets are protected by federal and state laws during the nesting season, which is generally accepted as from Feb. 15 through Sept. 1. There is no legal impediment to taking the (non-native) trees down at this time of year, however. Caltrans fears a possible work interruption if the trees were left standing.

The PWA and other environmental groups, including the Madrone Audubon Society, have asked for mitigation — the planting of native trees, such as Fremont Cottonwoods in the uplands at the western part of Shollenberger Park, but Caltrans will only come up with a "landscaping" plan after all construction is done, which would be years from now, and it is not certain even then if money would be appropriated for tree planting and maintenance there.

Many local residents, as well as visiting birders, have enjoyed observing nesting in the colony from the Shollenberger trail near the observation deck. While the egrets and herons may move to another active colony in the Petaluma Wastewater Ponds next year, that facility is not open to the public for colony viewing.

Recently, representatives of PWA and Madrone met with the City of Petaluma to see if a plan could be developed to place cottonwoods and oaks in the park uplands.

It would take years for the trees to be mature enough for nesting, but the sooner the process is started the sooner we might have a new Shollenberger Colony for the nesting birds and those who enjoy watching them.

(Bob Dyer is a Petaluma resident, bird enthusiast and senior docent for Petaluma Wetlands Alliance, which is a committee of the Madron Audubon Society.)