I had to laugh recently when I noticed a chain reaction going on in a Great Blue Heron nest I was watching. There were five chicks, and one of them yawned. At least I presume it was a yawn, though perhaps it could have be re-aligning its beak or perhaps cooling off. Exactly like humans, each of the remaining four birds followed suit and proceeded to stretch their beaks open wide in succession. It struck me as quite comical, especially when I discovered myself yawning as I observed the heron chicks doing the same.
In New England, Dark-eyed Juncos typically have two broods in a summer. The second-brood nest in the photograph contains the first of probably four or five eggs which are laid one day at a time. The egg lies on a soft lining made from the hair of a White-tailed Deer. Unlike most songbirds, Dark-eyed Juncos build their nests in a wide variety of sites, from the ground up to eight feet high in trees. Often they are in a small cavity on a sloping bank (well hidden by surrounding grass), under a protruding rock or among tree roots. But they’ve also been found under fallen tree trunks, on supports underneath houses on stilts, in barns or lofts between hay bales, in vines on the sides of buildings, on window ledges and light fixtures and in hanging flower pots. It’s not unheard of to find a Dark-eyed Juncos relining the old nest of an American Robin.
Great Blue Heron chicks are getting big enough so that you can easily observe them (can you find all four?). Occasionally you can even detect flies and other insects buzzing about them, which, given the fact that nest sanitation is not a priority for herons, is not surprising. While the parents do toss the eggshells out of the nest, feces, partly eaten prey and even dead chicks often remain in the nest. Also, parents feed their young by regurgitating into the nest and the chicks will regurgitate when disturbed. Unlike most song birds, Great Blue Herons re-use their nest year after year. It is quickly apparent why they add more sticks and boughs to their nest every breeding season – were that housekeeping for humans was that simple!
The nesting habits of Cliff Swallows are fairly unusual in that these swallows are colonial nesters. Here in the East you can find 20 or 30 of their nests under a bridge or the eaves of a barn (and occasionally on cliffs). In the West, colonies consist of up to 3,500 nests! The construction of their gourd-shaped nest requires between 900 and 1,200 trips to mud puddles or stream banks, where they gather a mouthful of mud in the form of a pellet. Often two swallows will build nests side-by-side, sharing the wall of mud that separates them. Unfortunately, according to the most recent Vermont Breeding Bird Atlas, the Cliff Swallow population in Vermont has declined by 48% in the past 25 years, a fact which is attributed to competition with House Sparrows, a decline in insects due to diminishing farm land, and destruction of nests by humans. These birds are more important insect predators than ever, with the bat population having suffered such a decline recently due to white-nose syndrome.
Great Blue Herons are returning to their breeding grounds in northern New England, where they typically nest in colonies. Unlike the nests of songbirds, heron nests are re-used year after year. While an individual heron does not usually choose the same nest every year, they usually return to the same colony. While some colonies are active for only a few years, some have been known to be active for over 70 years. Because nests can be located up to 100 feet high in a tree (typically a dead snag in the Northeast), you rarely have a bird’s eye view of nesting activity. However, if you go to Cornell’s new live great blue heron web cam site (http://www.allaboutbirds.org/page.aspx?pid=2433 ) you can see every movement made by the great blue herons currently nesting in Sapsucker Woods in Ithaca, NY.
The red-tailed hawk nest that produced two chicks last summer is once again occupied by a pair of red-tails. A conifer sprig adorning the outside of the nest was the first clue that a second brood might be in the works. Yesterday I saw both male and female return to the nest carrying strips of bark, which the female applied to the lining of the nest. Mid-March is when red-tails typically are building or refurbishing their nest and laying eggs. They begin incubating as soon as the first (of 2 – 3) egg is laid, with the male and female both participating. This photograph was taken at the changing of the guard.
Eastern bluebirds have already been seen checking out nest boxes – behavior that usually isn’t observed for another month or so. Interestingly, even though most people religiously clean out their bluebird boxes every year prior to the nesting season, experiments show that bluebirds prefer nesting boxes containing old nests. While breeding has not yet begun, it won’t be long before males will be trying to attract females to their nest site by carrying material in and out of the hole, perching, and fluttering their wings. After the males choose the nest site and perform for a mate, the females actually do the hard work of building the nest.
Like the majority of songbirds, American goldfinches use their nest only once — to raise one brood — and do not return to it after their young have fledged. This time of year, when leaves have fallen off of shrubs and trees, is a great time to try and locate where birds you saw all summer nested. Just as each species of bird has its own song, each species of bird builds a nest unlike those of other species. By noting the habitat in which it’s built, the material with which it was built, and the dimensions of a nest, it is often possible to determine the species of bird that constructed it. Female American goldfinches build a very neat nest composed of plant fibers, and line it with the down of cattails or thistles. The walls are quite thick, making it quite durable – the nest in the photograph even withstood the wind and rain that Irene delivered this fall. While it’s fun to hunt for nests, bear in mind that you need a federal permit to collect them.
American goldfinches are late nesters – it is not uncommon for them to be raising young in August, and occasionally even into September. Recently while walking through a wet meadow, I became aware of a sudden burst of activity to my right. Unbeknownst to me, I had come quite close to an American goldfinch nest which was full of nestlings on the brink of fledging. As I passed by, the young burst explosively from their nest. Two fluttered to the ground and quickly sought cover, one flew a short distance into some shrubs, and one remained in the nest. Regardless of where they sought shelter, the young will be fed and cared for by their parents for the next three weeks or so.
While the nestlings of most species of birds have fledged, some cedar waxwings are still incubating eggs. Known for being one of the last species to nest, a waxwing on a nest in mid-August is probably on its second brood. Both the male and female collect nesting material, but it is the female who does most of the nest construction, and all of the incubation of the eggs. The cup nest is constructed with a wide variety of material, including twigs, grasses, cattail down, moss, string, horsehair, dead leaves, cloth, shredded bark, roots, leaves, ferns, stalks of herbs and flower blossoms. Occasionally the exterior of the nest is decorated with ornate plant material, such as the lichen (Usnea , or Old Man’s Beard) in the photograph.
A smelly nest is a dead give-a-way to would-be predators, so most birds make an effort to keep their nest fairly clean. (In addition, if the nestlings’ down feathers get matted, they cannot assist in keeping the young birds warm.) While the young of some birds, such as raptors and herons, defecate at or over the edge of the nest as they age, the waste of many young songbirds is excreted in what is called a fecal sac – a nice, tidy bundle which the parents carry off and drop at some distance from the nest. Some species of birds actually eat their nestlings’ fecal sacs when the nestlings are very young, as the sacs still contain some nourishment.
The bald eagle previously photographed on its nest in May has successfully raised two nestlings, both of which may fledge in the near future. The young eagles are all brown — it will be four years before they attain the white head and tail of an adult. As they near their two-month-old date, the young eagles are flapping their wings and lifting themselves up several inches in the air and onto nearby branches as they develop their flight muscles and practice landing. Research indicates that up to half of all eagle nest departures are unsuccessful, and the young may remain on the ground for weeks before regaining flight ability. While the parents do continue to feed them, the fledglings are very vulnerable to predators.
The red-tailed hawk nest which has been featured several times this summer is empty! Yesterday I watched as the remaining young red-tail climbed out on a branch above the nest and flew over the adjacent field, landing in a tree on the edge of the field. Because recently-fledged red-tailed hawks tend to stay very near their nest for the first few days (and sometimes weeks) after fledging, this may well have not been its maiden flight. Nevertheless, it was a wonderful sight to see!
Unlike most birds’ eggs, those of the red-winged blackbird hatch asynchronously – that is, they don’t all hatch at the same time. Instead, their hatching is spread over several days. During seasons when food is short, the young which hatch last often starve, as the earlier-hatched young, being larger and stronger, are the first to be fed, and thus deprive their siblings of food. Having eggs hatch in succession is believed to be an adaptation that allows the size of the surviving brood to balance with the amount of available food.
If ever there was a species which defied the notion that males don’t participate enough in raising their offspring, it would be yellow-bellied sapsuckers. Without fail, the male parent keeps up with his mate in numbers of visits to their nesting hole, as well as the amount of food he collects and brings to the nest. He also partakes in nest cleansing. Often, when the male and female of a species’ plumage is similar, as in woodpeckers, you will find that that they share rearing responsibilities. The young of cavity nesters mature more slowly than open-nesters because their nest site is safer. They also leave the nest at a relatively later stage of development, when they can fly well, even though they have no room to practice flapping their wings.