An online resource based on the award-winning nature guide

Bird Nests

Black-and-White Warblers Raising Young

6-14-19 black-and-white warbler nest 0U1A0066One of the first warblers to return to its northern nesting grounds, the (female) Black-and-White Warbler has already built a nest, laid and incubated 4-6 speckled eggs and is now brooding and feeding nestlings.

Finding a Black-and-White Warbler nest can be challenging – these bark-foraging insect eaters usually build their well-hidden nest on the ground at the base of a tree, rock, stump or fallen log. Tucked into vegetation with the rim often at ground level, their 5-inch diameter nest blends into its surroundings. Bark strips, grass, dry leaves and pine needles are used to construct the nest which is lined with moss, horsehair and dried grasses.

The male helps the female feed the nestlings and defend the nest. Female Black-and-White Warblers have been observed performing “rodent run” distraction displays, in which the bird assumes a hunched posture and drags its tail, luring potential predators away from the nest.

The Brown-headed Cowbird is a major threat to Black-and-White Warblers as it frequently parasitizes their nests. One documented Black-and-White Warbler nest in Michigan contained 10 eggs, eight of which were laid by cowbirds. (Thanks to Susan and Dean Greenberg for photo opportunity.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Why Do Birds Turn Their Eggs?

5-31-19 C. goose turning eggs 1B0A8783It’s common knowledge that birds periodically turn their eggs when they are incubating them, but have you ever stopped to ask why they do this. One assumes that if this action weren’t critical to the incubation process, it wouldn’t be practiced, and science bears this out. According to Audubon, birds turn their eggs to make sure the embryo gets enough albumen – the white part of the egg that contains water and protein and provides essential nutrients to the developing embryo. Too little albumen leads to an underdeveloped and often sickly chick. (Photo: Canada Goose turning eggs)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Great Horned Owl Nestlings About To Fledge

5-17-19 great horned owls_U1A8938Great Horned Owls do not build their own nests, though they may provide some lining to an existing cavity or nest. Snags, cliffs and man-made structures provide nesting sites, but most commonly Great Horned Owls use the tree nests of other species such as hawks (especially Red-tailed) crows, ravens and squirrels. Most, but not all, nests are used for only one season. Pictured is a Great Blue Heron nest that has been usurped by a Great Horned Owl family – a feat achieved by the owls claiming the nest as early as February, prior to the return of herons.

After incubating her eggs for roughly a month, the female Great Horned Owl then broods her young for two to three weeks. The father’s role consists of bringing food to the female while she is incubating and brooding. She then tears the food up into bite-size pieces for the nestlings.

When the nestlings no longer need the heat their mother’s body provides, brooding ends but the mother stays with her nestlings until they fledge at about seven weeks of age. (Pictured: Great Horned Owl mother and two downy nestlings, roughly six weeks old. Thanks to Marc Beerman for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Great Blue Herons Building & Renovating Nests

5-6-19 great blue heron with white pine2_U1A7932A visit to a Great Blue Heron colony at this time of year will be rewarded with a great deal of avian activity, for their nesting season has begun and renovations are going full tilt. Males usually arrive first and settle on nests (more often as not using a different nest from last year) or begin building their own. Courtship then begins.

Great Blue Heron nests are found primarily in trees, up to 60 feet or more above the ground. Where trees are not available, herons will nest on the ground (usually only on predator-free islands). Males gather sticks and other nesting materials from the ground, nearby trees and shrubs, or from unguarded and abandoned nests, and females are usually responsible for the placement of the sticks into the nest. Nests are often reused for many years. Pictured is a Great Blue Heron returning to its nest with a branch from a White Pine tree which will be used for lining the nest. Nesting material is added throughout the nesting period.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Canada Geese Nesting On Beaver Lodges

4-29-19 c. goose on beaver lodge _U1A7241If you are fortunate enough to have a beaver pond near you, you should give the lodge more than a cursory glance this time of year. It is common to find Canada Geese nesting on beaver lodges, for obvious reasons – safety from most land predators. While Common ravens have been known to raid Canada Goose nests for eggs and goslings, the overall rate of survival of the goslings of lodge-nesting geese is very high.

A Canadian study showed that ponds with beaver lodges (and therefore Beaver activity which warms the water and thaws the ice) thaw at least 11 days sooner than ponds without Beavers, allowing early access to water for Canada Geese returning for the spring nesting season. Battles between pairs of geese vying for these coveted nesting sites are not uncommon.

Canada Geese have much to thank Beavers for. Not only can geese get an early nesting start on beaver lodges, they have a relatively safe spot to incubate their eggs and raise their young.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Changing of the Guard

5-11-18 red-bellied woodpeckers3 _U1A2313

In approximately 85% of bird species, both the male and female of a mating pair contribute to the feeding and guarding of their offspring. Red-bellied Woodpeckers are of this ilk. Both members of a pair help excavate a nest cavity, incubate the eggs, brood the young and feed the nestlings for up to 10 weeks after they fledge. As seen in this photograph, when tending to their nestlings, one member of a pair wastes no time in departing as soon as its mate appears.

Thanks to the extension of the Red-bellied Woodpecker’s range northward, even northern New Englanders now have the opportunity to observe the nesting behavior of these medium-sized woodpeckers. (Photo: female Red-bellied Woodpecker leaves nest as food-bearing male arrives. Note continuous red crown on male, which is broken in female.) (Thanks to Sadie Brown for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Common Grackles Nest-building

4-23-18 common grackle 0U1A0687

Common Grackles are hard to miss and hard to mistake for any other bird, with their yellow eyes, iridescent bronze or purple plumage and long, keel-shaped tails. Most of the spring migrants have reached their breeding grounds, and courtship, mating and nest-building are underway.

Because grackles begin reproduction so early in the season, conifers are the nesting site of choice due to the cover they provide. Females tend to choose the actual site for a nest, and in so doing can be quite fickle, often abandoning partially constructed nests and selecting alternative sites. They earn this right, as they’re usually doing all the construction work, although males have been observed with nesting materials, helping to build and repair nests.

Look for their 6-8”-diameter, large bulky nests near water, agricultural fields or near human habitation. They are usually built four to twenty feet above the ground. If you find a bird on the nest, it will most likely be an incubating female (slightly less glossy than male) – males not only do not have a brood patch and do not participate in incubating the eggs or brooding the young, but roughly half of the males desert their mates during this time. Those that do remain participate in the feeding of their young nestlings.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.