Notes about your surroundings.

Birds of Spring--This year’s spring bird migration, especially in April, has been an especially strong one, both in numbers and varieties of birds seen in Orange County.

“It’s been a good year for migrants,” said Doug Willick, who compiles a list of rare bird sightings in the county. Species of warblers, tanagers, grosbeaks and other perching birds have been plentiful at Huntington Central Park and other favorite birding spots in the county.

While sightings are down slightly so far this month, Willick expects the season to remain strong for the next week at least before tailing off for the year. In addition, some late migrants--such as willow flycatchers--are yet to arrive in the county.

“Presumably, there’s still time for a good push of migrants before the season kind of poops out,” Willick said.

The healthy spring migration has been accompanied by a large number of unusual sightings. Vagrant species--birds that stray from their normal migration paths into Orange County--will be seen with increasing frequency as the normal migration season winds down.

So far, sightings include:

* Gray flycatcher, April 21 and May 6, Shipley Nature Center at Huntington Central Park.

* Green-tailed towhee, April 21, Environmental Nature Center, Newport Beach.

* Black-footed sparrow, April 23 and 24, Huntington Beach.

* Yellow-breasted chat, April 21, Environmental Nature Center.

* Yellow-headed blackbird, since late April, Huntington Central Park.

* Palm warbler, May 3, Huntington Central Park.

* Black and white warbler, May 5 at UC Irvine, May 8 at Environmental Nature Center.

Swainson’s hawks, whose numbers have been in decline in recent decades, are not normally seen in the coastal counties (they are more common in the deserts). But seven have been seen in Orange County so far this season: four over UC Irvine on April 5, one over Tustin on May 3 and two over Westminster on May 4.

Meanwhile, it is well into nesting season for many resident birds as well as migrating birds that nest in the county. “Some already have young out of the nest,” Willick said.

Natural History Tour--The Natural History Foundation of Orange County and the UC Irvine Alumni Assn. are accepting reservations for a natural history tour from Aug. 21-30 through Yellowstone, Grand Teton and Glacier national parks. The guided tour includes exploring the Rocky Mountains, as well as a float trip on the Snake River and crossing the Continental Divide on the Going-to-the-Sun Highway in Glacier National Park. Visits to the Old Faithful geyser, the multihued Paint Pots and the Grand Canyon are also included.

The tour cost of $1,599 per person includes round-trip air and land transportation from the Newport Beach-Irvine area, lodging, some meals, naturalist guides and sightseeing. For more information, call the foundation at (714) 640-7120 or the alumni association at (714) 856-7361.