Northern Mockingbirds: Aggressive Defenders of Nest & Young
Besides being known for their vocal repertoire, Northern Mockingbirds are famous for pugnacious defense of their territory, nest, and young. Even more than most songbirds, Northern Mockingbirds aggressively stand guard over their nestlings as well as their young fledglings. Potential predators risk being mobbed and chased by nesting mockingbirds. While the female incubates, the male spends most of his time perched high on trees or rooftops, acting as a sentinel, and will chase away any animal (including humans) that approaches the nest. Northern Mockingbirds have also been known to join forces with other birds, including cardinals, thrashers and doves, to chase away potential nest predators.
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Cedar Waxwings Feasting on Fruit
Cedar Waxwings are strictly fruit eaters in the winter, expanding their diet to include insects during the warmer parts of the year. As their name implies, one often finds these birds in areas where there are a lot of cedars, as they’ve historically fed on cedar berries in winter. However, they increasingly rely on the fruit of mountain ash as well as apple, crabapple and hawthorn in the Northeast. Waxwings run the risk of intoxication and even death after eating fermented fruit such as the apples pictured. In recent years Cedar Waxwings have started feeding on the fruits of invasive honeysuckles, a habit which ornithologists feel might be responsible for a shift in waxwing distribution as well as regional population increases.
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Pine Grosbeaks May Be A Rare Treat This Winter
Several members of the Finch family of birds periodically fly south of their range into southern Canada and the northern U.S. during the winter in search of food. Pine Siskins, Common and Hoary Redpolls, American Goldfinches, Red and White-winged Crossbills, Purple Finches and both Evening and Pine Grosbeaks participate in these irruptions. Whether or not these species extend their range further south in any given year has much to do with their diet and its abundance or lack thereof on their wintering grounds . According to Ron Pittaway’s 2016-2017Finch Forecast (http://ebird.org/content/canada/news/ron-pittaways-winter-finch-forecast-2016-2017/ ), many of these birds will have a difficult time finding natural food sources this winter in Southern Ontario and the Northeast due to poor cone crops. Some may head north or west, where crops are much better.
Even if there were plenty of cones in the Northeast this year and many Canadian seed-eating finches were headed south of their normal range, we might not see large numbers of Pine Grosbeaks. This is due to the fact that the Pine Grosbeak’s diet is not limited to seeds, but includes buds, insects and fruit. Most of these birds are staying north this winter because of an excellent crop of Mountain-ash berries across the boreal forest. They eat these and other fruits by biting through and discarding the pulp and crushing the seed (which gives them a slightly unkempt look). We will see some — there have been several sightings of mostly small flocks of Pine Grosbeaks in New England in the past few weeks, lingering just long enough to consume what European Mountain-ash berries and crabapples they can find. But those of us who see them are very fortunate this year. (Photo: female Pine Grosbeak eating crabapples.)
Thank you to all of you who so kindly wished me well. I’m sure those wishes are what hav me bright-eyed and bushy-tailed once again!
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Nestling or Fledgling?
We are at the time of year where finding a young bird on the ground is not unusual, and many well-meaning people assume that if a bird can’t fly, it has been abandoned by its parents. While some of these birds may be young that have fallen out of their nest, the fledglings of many species spend as many as two to five days on the ground before they can fly any distance. While they are on the ground, the birds are cared for and protected by their parents and are taught vital life skills (finding food, identifying predators, flying). To deprive such a fledgling of this developmental stage by removing it from its parents is to lessen its chances of survival, so it’s behooves us to be able to tell whether or not a young bird belongs out of the nest or not.
If the young bird is nearly naked or covered with down, not quill feathers, or its eyes haven’t opened, it is obviously a nestling. If you can’t find its nest, a berry basket in the vicinity of where you found it, suspended from a branch, is a good facsimile. Birds have a poor sense of smell and very strong parental instincts and more often than not continue to care for their young after a disturbance, although it may be a few hours before they do so. If, after several hours, there is no sign of a parent, a local museum or nature center should be able to direct you to a nearby wildlife rehabilitator.
Fledgling birds, birds that have voluntarily left their nest, are usually fully feathered and have a very short (one inch or so) tail. They are able to walk, hop and flap, and they may attempt short flights. You may not see them, but a parent or two is nearby, keeping an eye on them, feeding them and teaching them how to survive on their own (see insert). These are the birds that humans often mistakenly “rescue.” If you find a fledgling, it should be left alone or, at the most, placed in a nearby shrub. If possible, keep people and pets away so the parents will continue to care for it until it can fly. (Photos: fledgling and attending adult Common Grackle)
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White-breasted Nuthatches Raising Young
White-breasted Nuthatches maintain their pair bond throughout the year. In the spring, after mating, the female builds her nest, lining the tree cavity (natural or old woodpecker hole) with fur, bark, and lumps of dirt and then making a cup nest of grasses and bark inside the cavity. She then lays her 5 – 9 eggs and incubates them for roughly two weeks, during which time the male brings her food.
After the eggs hatch, both parents provide their nestlings with food until they fledge. Initially the female remains with the young, and the male brings food for both her and the nestlings. His trips become more frequent during the first few days, starting at about 7 trips an hour and increasing to 13. After three or four days the female also participates in food gathering, as much or more than the male.
The average day length in June is approximately 15 ½ hours. At 26 deliveries/hour (13 per parent) that comes to a total of around 400 foraging trips a day for the majority of the 26 days before White-breasted Nuthatch nestlings fledge. Impressive, especially when you consider that many of these trips involve not only delivering food but also removing the nestlings’ fecal sacs.
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The Ubiquitous Yellow-rumped Warbler
The Yellow-rumped Warbler (Setophaga coronata), formerly referred to as a Myrtle Warbler, is not hard to find during its migration due to the large numbers that pass through (as well as stay to breed in) central and northern New England. These tiny jewels, also known as “butter-butts” because of their bright yellow rumps, are common and widespread.
Yellow-rumps are known for the diversity of their feeding techniques as well as their diet. You are as likely to find them clinging to a tree, probing under bark or foliage gleaning for insects as you are finding them taking short bursts of flight off of a branch to snag an insect in the air. These warblers are insect-eaters during the summer and consume a large amount of fruit during the winter. Their ability to digest the waxes in bayberries makes them unique among warblers, and allows populations to winter along the coast as far north as Nova Scotia.
The presence of “pantaloons” on this image of a male Yellow-rumped Warbler may be due to courtship behavior. Males hop from perch to perch, fluff out their feathers, raise their wings, erect their crown-feathers, and continuously chip in an effort to attract a female.
Should you choose to use your ears to locate this coniferous forest-loving warbler, its song can be heard at http://musicofnature.com/mary-holland/yellow-rumped-warbler/ . (Sound recording © Lang Elliott – langelliott.com)
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Evening Grosbeaks Returning From Southern Wintering Grounds
Until the mid-1800s evening grosbeaks were considered uncommon to rare east of the Mississippi River. Today evening grosbeaks can be found year round in northern New England.
The eastern expansion of evening grosbeaks is mainly attributed to the accessibility of winter food in the form of box elder fruits. These trees were planted as windbreaks on the prairies, and as ornamentals in northeastern cities. Their seeds persist into the winter, allowing erratic winter flocks from the west to overwinter further east. Some overwintering birds remained here to nest, and thus began the expansion of their breeding range. Some ornithologists also believe that the recurring spruce budworm outbreaks in boreal forests facilitated eastward expansion by providing food in the summer months. Feeding birds became popular in the 1930’s, and may also have contributed to this range extension.
In a typical year in the Northeast, many birds migrate south of their breeding grounds to spend the winter. From March to early May, most of these individuals return to northern and western coniferous forests to breed and we have a greater chance of seeing them at feeders (along with hungry bears). (Photo: male evening grosbeak. Note bill is beginning to show the green tint it has during the breeding season.)
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Mixed Emotions Greet Returning Common Grackles
The first common grackles of the year have been sighted — not something to be celebrated by all, for there is a lot to dislike about common grackles. They are among the most significant agricultural pest species in North America, causing millions of dollars in damage to sprouting corn. They also eat other birds’ eggs and nestlings, and occasionally kill and consume adult birds. However, one has to admire the intelligence that some of these actions plus others reflect.
These members of the icterid, or blackbird, family have learned to follow plows in order to consume the invertebrates and mice that are exposed. Grackles engage in “anting” – letting ants crawl all over their bodies in order for the ants to secrete formic acid which may then rid the grackles of parasites. They rotate acorns between their mandibles, utilizing a ridge inside their mouths to open the acorns. And at least one common grackle was crafty enough to live for 23 years before being killed by a bird of prey – an extraordinarily long life for a passerine, or perching, bird.
Regardless of how we regard any one species, the phenomenon of spring migration and the remarkable birds that survive its rigors every year are cause for celebration.
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Hermit Thrushes Still Singing
The woods have become relatively quiet in the last few weeks. A majority of songbirds have mated and nested, so there is no need to reinforce pair-bonding with song. However, some late nesters, including the Hermit Thrush, are still on eggs and the males are still singing.
The Hermit Thrush makes up for its rather drab appearance with its melodious, haunting, flute-like song. The Hermit Thrush’s song is similar to that of its close relative, the Wood Thrush, but it starts with a single, clear note which the Wood Thrush’s song lacks. The Hermit Thrush doesn’t sing during migration or on its wintering grounds, so we are now privilege to its last lyrical songs of the year. To hear a recording, go to http://langelliott.com/mary-holland/hermit_thrush_by_Ted_Mack_Adirondacks_1994.mp3. (Sound recording © Lang Elliott – langelliott.com & miracleofnature.org)
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Male Ruby-throated Hummingbirds Leading Life of Leisure
Equality of the sexes has yet to reach some avian species. Among them is the Ruby-throated Hummingbird, the only species of hummingbird that breeds in the Northeast. After courtship and mating takes place, the male has next to no contact with his mate(s), possibly visiting them during nest construction, but he does not lift a feather to assist in raising their offspring. By herself the female selects a nest site, builds a nest (six to ten days), lays two eggs, incubates the eggs (12 – 14 days), broods them (9 days), removes their waste, or fecal sacs, for the first two days (after which the nestlings eject their droppings from the rim of the nest) and feeds them (a total of 22 – 25 days — while young are in nest, and for 4 – 7 days after they fledge). Males spend the summer feeding, preening, bathing, stretching their wings and fanning their tails, sleeping, roosting and sunbathing. Not a bad life for him; an exhausting one for her. (Thanks to Jeannie Killam and Terry Ross for photo op.)
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Tree Swallow Nestlings Well Fed
Tree Swallow parents begin feeding their four to seven nestlings as soon as they hatch, and they continue doing so until their young depart the nest and sometimes for several days afterwards. The adult carries food in its bill and places it directly into the open mouth of a begging nestling. The small insects gathered by the parent may be formed into a rounded ball, or bolus, which they hold in their mouth or throat (often not visible to an observer). Both parents feed the nestlings, together averaging about ten to twenty deliveries per hour. During periods of peak nestling demand, parents may feed as many as 6,000 to 7,000 insects in a single day. (Thanks to Jeannie Killam and Terry Ross for photo op.)
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Northern Waterthrushes Singing
If it is not singing, the Northern Waterthrush, a large wood warbler and not a thrush, can be recognized by its bobbing body and wagging tail. However, its loud, ringing song is the most diagnostic characteristic of this species, and allows one to distinguish it from its look-alike relative, the Louisiana Waterthrush. The primary song of the Northern Waterthrush has three parts, which are said to sound like a vigorous, rapid “sweet sweet swee wee wee chew chew chew chew.”
The Northern Waterthrush also has a flight song which is given on its breeding ground, typically in the evening. This song usually starts with loud, sharp, chips of increasing frequency, delivered from the ground or a low perch. The bird then flies upward through and above the canopy, singing snatches of primary song but quicker and longer, framed in a hurried jumble of half-call/half-song notes.
To hear the primary song of the Northern Waterthrush, go to http://langelliott.com/mary-holland/northern_waterthrush_1_NY.mp3. (Sound recording © Lang Elliott – langelliott.com & miracleofnature.org)
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Cliff Swallows Building Nests
You may have heard of “lining” bees – following one honeybee after another, tracking them to their honey-laden hive. Recently I lined Cliff Swallows. My initial observation was of several swallows on a mud flat in the middle of a river, loading their beaks with mud and taking flight, all in the same direction. Knowing that their nests are made of mud pellets (900-1,200 of them), I knew that they must be nesting somewhere in the vicinity. The length of time between their departure from and return to the mud flat was quite short, so I deduced that the distance they were carrying the mud and depositing it couldn’t be too great. After heading off in the direction that the swallows were flying, I eventually discovered the very beginning of a colony of Cliff Swallow nests under the eaves of a nearby barn.
The building of a nest requires not only finding a source of mud, but also ferrying lumps of it (in their beaks) back to the nest site many, many times. Once a source has been found, its location is made known to all members of the colony, and they all make use of it. Cliff Swallows belonging to the same colony not only use the same source of mud, but gather it together as a group, and return to work on their nests all at the same time. They work in roughly half-hour shifts, after which they all take a break and forage for insects for ten minutes or so before resuming work.
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Waxwings Supplementing Sugary Fruit Diet With High-Protein Insects
The diet of both Cedar and Bohemian Waxwings is primarily sugary fruits throughout most of year. Research shows that they can subsist on this diet exclusively for as many as 18 days. However, in winter when feeding on fruits, they also feed on buds and available insects. In warmer months, waxwings will fly out over water from exposed perches, much like flycatchers, and snatch emerging aquatic insects such as mosquitoes, midges, mayflies, caddisflies and dragonflies out of the air. They also glean for vegetation-borne insect prey, such as scale insects. At this time of year they are taking advantage of winter stonefly hatches over open streams. (photos: bohemian waxwing & stonefly)
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Common Grackles Returning
Male Common Grackles have started to arrive on their northeastern breeding grounds (females will arrive in another week or so), having migrated from southern U.S. Common Grackles typically migrate in large flocks containing hundreds of birds, not all grackles. Red-winged Blackbirds, Brown-headed Cowbirds, European Starlings and occasionally American Robins can be found alongside Common Grackles in these migrating flocks. In the early 1990’s, magnetic material was found in the heads and necks of Common Grackles, indicating that the geomagnetic field may play a role in their migratory navigation.
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Mourning Doves Calling
The mournful lament of the male mourning dove is often one of the first songs heard in the early spring. The frequency of this call builds to a peak from mid-May to mid-June. As in many other pigeons and doves, the Mourning Dove’s main call, or “perch coo” (coo-oo, OO, OO, OO) is an advertising call, sung in order to attract a mate. Unmated males often establish perches within their territory from which they repeatedly sing.
A shorter nest call is used by a paired male to attract his mate to a potential nest site. The male then gathers nesting material and presents it to the female while standing on her back. While she constructs the nest, he continues to use the nest call to maintain a bond with his mate. Once the nest is built, this call diminishes. You can hear Mourning Dove calls at http://www.allaboutbirds.org/guide/mourning_dove/sounds, although to my ear, it’s hard to distinguish the perch call from the nest call in these recordings.
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Male American Goldfinch’s Seasonal Plumage
Most songbirds have one complete molt every year, in the late summer. Some, like the American goldfinch, have another (partial) molt in the spring. Last fall male goldfinches molted, replacing many of their bright yellow feathers with drab, greenish-gray feathers, so that they closely resemble females during the winter. Goldfinches start their partial molt in February, and in the next month or two, males will once again become bright yellow beacons. No-one can illustrate the subtle seasonal plumage changes of a male American goldfinch better than David Sibley: http://www.sibleyguides.com/2012/05/the-annual-plumage-cycle-of-a-male-american-goldfinch/ (Photo: male American goldfinch in March)
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Black-capped Chickadees Starting to Build Nests
At least two to four weeks before one would expect to find a black-capped chickadee building a nest, one was busily collecting hairs shed by my chocolate lab yesterday. In addition to fur, chickadees line their nest with grass (not available yet here), down and moss (hard to come by with two feet of snow still on the ground). Chickadees are able to nest this early in part because they nest in cavities, which offer them protection from the elements. Not having bills strong enough to hammer out cavities in living trees, chickadees rely heavily on rotting stumps for nest sites — the wood in them is punky and easy to remove. Birch, poplar and sugar maple snags and stumps are preferred nesting trees. If you want to provide chickadees and other birds with nesting material, take advantage of the fact that dogs and cats are shedding now, and recycle their fur.
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Returning Red-winged Blackbirds Announce the Arrival of Spring
Regardless of the deep snow that remains on the ground and the frigid temperatures we’ve had recently, spring has announced itself with the arrival of red-winged blackbirds this week. Most redwings that breed in New England migrate approximately 500 miles further south to spend the winter. In the spring, males begin migrating first, flying north in flocks during the day to their breeding grounds. (In the fall, females depart first.) While they eat primarily insects during the breeding season, redwings subsist mainly on seeds and grain this early in the season. Before you know it, females will return, and up to fifteen of them will be nesting on the territory of each male (though he doesn’t sire all of the nestlings).
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Mourning Dove Diet
Seeds, including cultivated grains, grasses, weeds and berries, make up 99 percent of a Mourning Dove’s diet. Because they can find enough food to sustain themselves, Mourning Doves are permanent residents, remaining year round, even in northern New England.
These birds feed on the ground and in the open, consuming 12 to 20 percent of their body weight per day, or 71 calories on average. Mourning Doves swallow the seeds and store them in an enlargement of the esophagus called a crop. Once their crop is filled (the record is 17,200 bluegrass seeds in a single crop), they can then fly to a protected area where they can safely digest their food.
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Tufted Titmice Caching Seeds for Winter Consumption
Tufted Titmice and Black-capped Chickadees are in the same family (Paridae), and share several traits, one of which has to do with securing food. They are both frequent visitors of bird feeders where they not only take seeds and soon thereafter consume them, but they also collect and cache food throughout their territory for times when there is a scarcity of food. Tufted Titmice usually store their seeds within 130 feet of the feeder. They take only one seed per trip and usually shell the seeds before hiding them.
In contrast to most species of titmice and chickadees, young Tufted Titmice often remain with their parents during the winter and then disperse later in their second year. Some yearling titmice even stay on their natal territory and help their parents to raise younger siblings.
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Gray Catbird Stragglers Passing Through
Gray catbirds begin their nocturnal migration to wintering grounds in late August and early September. The last of the stragglers are now passing through northern New England. Catbirds winter from the southern New England coast south to Panama, with concentrations on the U.S. Gulf coast and the Yucatan Peninsula. Those individuals that winter in the Yucatan Peninsula and Central America cross the Gulf of Mexico, and in order to do so they put on so much fat (during fall migration their mass may increase to 150% of lean body mass) that it approaches the upper limit of what flight allows.
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Red-winged Blackbirds’ Diet Changing From Insects to Seeds
During the breeding season, insects make up the bulk of a Red-winged Blackbird’s diet, but during the rest of the year, plant seeds are preferred. While the seeds of ragweed, corn, oats and smartweed are more staple food sources, cattail seeds are not overlooked. At maturity, and under dry conditions, the cattail spike bursts, releasing the seeds (some estimates are as high as 228,000 seeds/spike). When this happens, blackbirds take advantage of the easily accessible source of food, but the minute size of each seed (.0079 inches long) means obtaining a meal is a labor-intensive endeavor.
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