Bombay Hook National Wildlife Refuge, 2591 Whitehall Neck Road, Smyrna, announced its April calendar of events.

— Impoundment bird identification tour: 10 a.m. to noon April 6. Join Volunteer Terry Willis for a bus tour of the refuge impoundments and bayside. Look for and identify the winter waterfowl, resident herons and perhaps some shorebirds along with eagles and other passing raptors. Viewing scopes will be provided. To register: 653-9345 or tina_watson@fws.gov.

— Bird walks with Marcia Poling: 8 to 10:30 a.m. Wednesdays, April 17 through May 29. Join Marcia Poling, avid birder and artist, to look for early songbird arrivals from Mexico and South America. The group will walk several trails in search of songbirds and will stop to identify shorebirds along the wildlife drive. Meet at the Visitor Center.

— Jr. Rangers celebrate Earth Day: 9:30 a.m. to noon April 20. New and returning children ages 7-11 are welcome. To register: 653-9345 or tina_watson@fws.gov.

— Toddlers and guardians free: 9 a.m. to 2 p.m. April 16. Toddlers/preschoolers ages 1-5 and their guardians are free on the third Tuesday of the month in March, April and May. Children are developing cognitive skills and being in nature can expose them to sights and sounds that might go unnoticed in their everyday setting. Take children on the wildlife drive, walk a trail, climb a tower, read a nature book and look at wildlife exhibits in the visitor center.

— Purple martin nest checks: 11 to 11:45 a.m. April 24 and 30. Joel Martin and Ray Gingerich will perform weekly purple martin gourd and house nest checks during April, May and June. Individuals can observe and assist with recording data, counting eggs and hatchlings, and after they hatch hold a chick. The nests need to be checked quickly to make sure the purple martins are not disturbed for a long period of time. Meet at the Visitor Center. Other dates are May 3, 8, 13, 18, 22, 28 and 31; and June 5, 10, 14, 19, 24, and 28.

— Beginning Birding Warbler Program: 10 to 11:30 a.m. April 27. Eileen McLellan and Terry Willis will give a presentation on the warblers migrating through Bombay Hook during the spring.

— Beginner birding warbler walk: 8 to 10 a.m. April 28. Walk on one or two trails along the wildlife drive with expert birders Eileen McLellan and Terry Willis. This will be an excellent way to practice skills learned at the Warbler Program the day before, or for anyone who wants to look for warblers.

— Tour of the refuge: 11 a.m. to 12:30 p.m. and 1:30 to 3 p.m. April 28. Join Volunteer Ray Cullom for a tour of the refuge. Find out how the refuge is managed for wildlife, visit different habitats and walk a trail. Meet at the Visitor Center.

The Wildlife Drive is open daily from a half-hour before sunrise to a half-hour after sunset. The Visitor Center is open from 8 a.m. to 4 p.m. weekdays, and from 9 a.m. to 2 p.m. weekends, beginning March 2.

Admission is $4 per vehicle.

For more, visit fws.gov/refuge/bombay_hook.