An online resource based on the award-winning nature guide

Cavity Nesting Birds

Black-capped Chickadees Still Nest-building

7-5-13  black-capped chickadee 006Black-capped Chickadees tend to be early nesters, often as early as April, as they build their nest inside a cavity where it is sheltered from the cold. Chickadees rarely re-use a nest, so one might guess that this Black-capped Chickadee with nesting material in its beak in early July has a second brood on its way. However, it is unusual for Black-capped Chickadees to have a second brood of young after the first has fledged. If they lose the first brood, they sometimes will re-nest, but it’s more likely that this chickadee is just a late nester, as nest-building can and does occur up until mid-July. Both members of a pair excavate a cavity in a rotting tree, stump or post and then the female alone builds the nest inside the cavity. The foundation of the nest is usually made of coarse material such as moss. The lining consists of softer, finer material such as deer hair, rabbit fur, or in this case, an aging chocolate Labrador Retriever’s hair.


Beaver Ponds & Waterfowl

6-5-13 mallard & ducklings 151The relationship between beavers and waterfowl is a strong one. In creating ponds and wetlands, beavers provide valuable waterfowl habitat. Beaver ponds are attractive to most dabbling duck species, particularly American Black Ducks and Mallards (pictured). Dead snags that are often found in beaver ponds provide Hooded Mergansers, Common Goldeneyes, Buffleheads and Wood Ducks with nesting cavities. During spring and fall, beaver ponds are used by migrating waterfowl, such as Green-winged Teal and Ring-necked Ducks, for the fuel they provide (aquatic invertebrates, plant seeds, tubers, buds and rhizomes). Waterfowl surveys in 2002 in Wyoming found that rivers and ponds with beavers had 75 times more ducks than those without beavers.


Hairy Woodpeckers Raising Young

6-3-13 hairy woodpecker looking right 330The chipping of hungry Hairy Woodpecker nestlings can easily be detected by human ears, even though it comes from deep within a tree cavity. One is reminded of how beneficial this species is when observing the steady delivery of food by these woodpeckers to their young. More than 75% of an adult Hairy Woodpecker’s diet consists of injurious insects, while the amount of useful insects and cultivated fruits that they destroy is insignificant. Beetle larvae (mostly wood-boring) make up 30% of the insects that are consumed, with ants ranking second, at 17%. Caterpillars, such as those pictured, comprise about 10% of an adult Hairy Woodpecker’s diet, but given this parent’s beakful, one wonders if the percentage is greater for nestlings.


Hooded Merganser

5-24-13 hooded merganser2  030Yesterday’s mystery duckling was a Hooded Merganser. Wood Duck and Hooded Merganser ducklings are very similar, however Wood Duck young possess a dark, horizontal line behind their eyes which Hooded Merganser ducklings lack. There are several ducks that nest in tree cavities in New England, including Wood Ducks, Common Goldeneyes, Common Mergansers and Hooded Mergansers. Hooded Merganser ducklings leave their nest cavity within 24 hours of hatching, in response to their mother’s calls below. They jump/climb up the wall of the cavity and hurl themselves out of the tree. Depending on where the tree is located, they fall either onto the ground, where they bounce like a tennis ball upon landing, or straight into the water. Hooded Merganser fledglings have been known to fall as far as 50 feet to the ground and then walk as far as half a mile with their mother to the nearest body of water.