Notes about your surroundings.

NESTING PLATFORMS: For more than 10 years, great blue herons have nested in eucalyptus trees at the Santa Ana River Lakes in Anaheim. The “lakes,” site of a fishing concession, are recharge basins controlled by the Orange County Water District near where Tustin Avenue crosses the Riverside Freeway.

Last year, 14 nests produced 12 great blue heron chicks. And once the herons finished nesting, double-crested cormorants used the same nests and successfully raised young. Five nests produced 11 cormorant chicks, the first time the birds are known to have nested in the county.

Ironically, increased nesting activity and perhaps other environmental factors have damaged the trees. In an effort to protect the bird habitat, artificial nesting structures will be built at the site by the County Environmental Management Agency, with advice from the state Fish and Game Department.

Erection of four nesting poles, each with three platforms, was to be completed in February but was delayed by a paper-work mix-up, according to Dale Dillon of the county environmental agency. His agency could put up the poles within two weeks, but that may be too late: herons at the site have already started to collect materials to reinforce nests from past seasons and will be laying eggs in the next few weeks.

Esther Burkett, a biologist for Fish and Game who is advising on the project, said erection of the poles may have to wait until next year if she decides the project will disturb the nesting birds too much. Whether the poles go up or not this year, the damaged trees will remain for the time being.

Burkett believes this is the first time in California that nesting structures of this type will be tried for great blue herons, although they have been used successfully in Minnesota.

The Santa Ana River Lakes site is the largest of several known great blue heron rookeries in the county (the rookeries are small, with only 24 to 30 total nests known in the county). Others include a few nests on an island in Anaheim Lake, some at undeveloped Wagon Wheel Regional Park, and at Irvine Lake.

SPEAKING OF BIRDS: Among the rare bird-sightings reported in January by Doug Willick, who compiles the sightings for American Bird magazine, is a pine warbler spotted at Yorba Regional Park on Jan. 14 and presumed to be wintering there. A common bird of the Eastern pine forests, this marks the first time the pine warbler has been recorded in Orange County.

An immature bald eagle spotted flying through Upper Newport Bay on Jan. 29 was only the second recorded sighting in the county in more than 10 years. Historically, the bird wintered in the county in small numbers.

The American white pelicans that descended on the east Anaheim area in unprecedented numbers (several hundred were counted) peaked in December and have been gradually leaving the area. Several dozen of the impressive birds remain and are often seen in the Santa Ana River Lakes area.