The refuge provides important habitat for birds that nest in cavities in trees. Some of the more noteworthy species are wood ducks, woodpeckers, owls, and prothonotary warblers. Although you may see some manmade wood duck boxes along the trail, these are mainly used by other species of wildlife such as owls and raccoons. Fortunately there are plenty of natural cavities for the majority of cavity nesters on the refuge.
Wood ducks are very colorful birds. Male wood ducks have a crested head that is iridescent green and purple with a white stripe leading from the eye to the end of the crest, and another narrower white stripe from the base of the bill to the tip of the crest. The throat is white and the chest is burgundy with white flecks, gradually grading into a white belly. The bill is brightly patterned black, white and red. Wood ducks are 19 to 20 inches long and have wingspans of 28 to 39 inches. The natural cavity openings that wood ducks use are 4 inches across and the cavities are 24 inches deep. Some wood ducks migrate, but some remain on the refuge year-round.
There are several species of woodpeckers that live on the refuge and live in cavities in trees. The most common and noticeable is the pileated woodpecker, a very large woodpecker 26 to 29 inches long with a wingspan of 26 to 30 inches. It is black with a white stripe under its eye and down its neck and a red crest on top of its head. It makes an oblong entrance hole for its cavity nests and the cavities are 10 to 24 inches deep. Pileated woodpeckers make rectangular holes when the forage in dead wood. Pileated woodpeckers do not migrate and on the refuge year-round.
A number of owl species also use the refuge. Barred owls are fairly common. Their call is easy to identify as the ‘who-cooks-for–you’ call. Barred Owls are large, stocky owls with rounded heads, no ear tufts, and medium length, rounded tails. They are 16 to 25 inches long and have a wingspan of 38 to 49 inches. They are mottled brown and white overall, with dark brown, almost black, eyes. The underparts are mostly marked with vertical brown bars on a white background, while the upper breast is crossed with horizontal brown bars. The wings and tail are barred brown and white. Barred owls nest in natural cavities 10 to 13 inches in diameter and 14 to 21 inches deep, and 20 to 40 feet high. Barred owls do not migrate and on the refuge year-round.
The most striking cavity nester on the refuge is the prothonotary warbler, a brilliant yellow bird with a deep yellow head and chest. It has black eyes, greenish back, white belly and undertail, gray wings without wing bars, and white spots on its tail. It is 6 inches long and has a wingspan of 8 inches. Its song is a sweet ‘tweet, tweet, tweet, tweet sung in one pitch. Its nest cup is 2 inches wide. Prothonotary warblers are neotropical migratory birds and arrive from Central and South America in April to breed. They are one of only two warbler species that best in cavities.