Saturday, June 30, 2012

Bird Nests, Houses and Cavities

Baltimore Oriole nest
Being a weaver, bird nests have always fascinated me. I love how birds use natural and man-made materials to build these amazing structures. This Oriole nest looks like it's attached precariously to a branch.

Baltimore Oriole at nest
The female of this species does the nest building, usually going back to the same area as in previous years, but not re-using the old nest. She will take material from a former nest to use in the her new one.

Bald Eagle nest

Bald Eagles build the largest nests or aeries of any North American bird. They will use the same nest year after year, adding material to it. Typically the nest is 5 feet across but may eventually be 13 ft deep and 8 feet wide, weighing 1 ton. One nest in Florida was found to be 20 ft.deep, 9.5 ft. wide and weighed 2.7 tons. This is the largest tree nest ever known.

Blue-gray Gnatcatcher
While observing a Gnatcatcher this spring, we followed her to the nest. It was well camouflaged with lichens covering the outside, mirroring the lichens covering the bark on the cherry tree where the nest was built.

Eastern Kingbird nest
This Kingbird was sitting pretty on her nest. The Kingbird is one of a few who will eject Brown-headed Cowbird eggs from the nest. Cowbirds don't build their own nests but parasitize other nests.

Red-eyed Vireo with nesting material

On a hike in the woods, we heard Red-eyed Vireos singing and saw this one with nesting material.

Red-eyed Vireo nest
We followed her and found the nest she was building in the fork of a branch.

Eastern Phoebe nest with young
The female Eastern Phoebe will build her nest on a sound structure, usually in a site protected from the weather. Phoebes will often re-use the same nest the following year.

American Robin nest with young
A female robin will often build her nest in unlikely spots but to her, it must have seemed a safe spot. Robins can have up to 3 broods in a year.

House Wren defending his nest site
House Wrens may be small but they are fierce defenders of their nest boxes. I observed one this spring relentlessly attacking a chipmunk until the chipmunk left the area. Every time I go outside, I too, get scolded.

Northern Flicker at nest hole
Both male and female Flickers excavate their nest cavity in a dead tree.

Tree Swallow in nest cavity
Even though we usually see Tree Swallows in houses around the edges of marshes and fields, they will nest in tree cavities. Unable to excavate cavities, they will use existing holes or natural cavities.

Tree Swallow in gourd-type house
Our Tree Swallows come back every year to nest in these gourd-type houses we put up in our field.

Eastern Bluebird feeding nestling

Our Eastern Bluebirds successfully fledged one brood, then started another in a different house. One day,  realizing I hadn't seen the bluebirds lately,  I looked at the house and saw 2 heads sticking out...........not baby bluebirds...............but..........

field mice
Field Mice!! How did they get into the house!?! I really don't want to think about it........

Tuesday, June 19, 2012

Wonderful Warblers - and How They Got their Names!

yellow-rumped warbler
   This isn't a picture of the Yellow-rumped Warbler's rump, it's a picture of the undertail coverts which are white. When I decided to blog about how warblers got their names, I found that Gerry didn't get a shot of the Yellow-rumped Warbler's rump, but I included the bird anyway. Take my word for it, it's yellow.

yellow-rumped warbler

There are two subspecies of the Yellow-rumped Warbler. Our eastern variety, the Myrtle, has a white throat whereas the western one, Audubon's, has a yellow throat. They both have yellow rumps; some birders call them "butter butts".

yellow warbler
The Yellow Warbler IS yellow; there are no wing bars, no eye rings or head streaking. They are uniformly yellow; the males are egg-yolk yellow with reddish streaks on their chests.

chestnut-sided warbler
The Chestnut-sided Warbler male is a well-named warbler for he does have chestnut-colored sides but the females and fall males do not. This warbler was virtually unreported during the time of Audubon and other early American naturalists, but has increased greatly in numbers since the clearing of eastern forests in the 1800’s. This is a bird of second growth, scrub and disturbed woodlands throughout its breeding range in North America.

blue-winged warbler
While the Blue-winged Warbler doesn't have sky blue wings (from a distance the wings look gray), in fact upon closer inspection they are slate-blue, with a tail to match.

magnolia warbler
This beautiful warbler with the black necklace was first discovered in magnolia trees in the 19th century by famed ornithologist Alexander Wilson while in Mississippi, thus its name. Although Alexander Wilson did call it a Black-and-yellow Warbler, its Latin name is Dendroica magnolia, so Magnolia Warbler stuck.

American redstart
The American Redstart got its name from the red patches on his tail and "start" comes from Middle English stert for tail. The intensity of the reddish-orange patches in the tail, wings and sides of the breast can vary. Gerry says it should be called the American Orange-start.

pine warbler
True to his name, the Pine Warbler is found in pine trees! This species only nests in pine forests, and is almost never found in deciduous forests except during migration. The Pine Warbler is the only warbler that eats large quantities of seeds, primarily those of pines. Truly living up to his name.

black-and-white warbler
Another aptly named warbler, the Black-and-white is commonly found foraging for insects while creeping along the trunks and branches of trees. This warbler has a very distinctive song. Imagine a squeaky wheel going around and around and you've got it; weesee, weesee, weesee..........

prairie warbler
The prairie warbler got its name in 1810 in south-central Kentucky when ornithologist Alexander Wilson first encountered the bird in scrubby habitat that today, we call a barrens. In 1810, these savanna-like barrens with scattered trees and a brushy understory were called prairies. Today you'll find a Prairie Warbler in shrubby fields, early regenerating forests, and other successional habitats, like power-line clearings and christmas tree farms.

common yellowthroat
I think the Common Yellowthroat should have been named the Masked Warbler! Sure both sexes have yellow throats but so do other warblers and there is a Yellow-throated Warbler already.........well no one asked me! The Common Yellowthroat is common though, probably the most widespread warbler in North America.  A recent study showed that males with large black masks were more likely to win mates than males with small black masks. I guess size does the bird world.

Tuesday, June 12, 2012

Rose-breasted Grosbeak

rose-breasted grosbeak
 The Rose-breasted Grosbeak is a pretty regular visitor at our house here in southeastern Vermont. This year we've seen 2 adults males and 2 adult females. There's no mistaking the male when it comes to identification - massive bill, black and white pattern and distinctive red patch on the breast.

female red-breasted grosbeak
The female is a bit drabber, looking like a large sparrow or finch. She has lemon-yellow feathers under her wings which are only visible in flight.

As I was looking at the images Gerry took of the male, I noticed something green in the corner of his bill.

A few frames later and you could get a better glimpse of........

I assume it's a caterpillar, or was a caterpillar. Besides using those massive bills for cracking sunflower seeds, grosbeaks also eat insects. 

 I'm sure both pairs are busy feeding young. Here's an interesting fact I found on the Cornell site - 'the nest of the Rose-breasted Grosbeak is so thinly constructed that eggs often can be seen from below through the nest'. We'll have to start looking!

Thursday, June 7, 2012

Great Blue Heron

   At 4 feet tall with a 6 foot wingspan, the Great Blue is our largest North American heron. 

Great Blues have specialized feathers on their chest that continually grow and fray. They comb this “powder down” with a fringed claw on their middle toe, using the down like a washcloth to remove fish slime and other oils from their feathers as they preen.

This Great Blue seems to like the birdhouses at Allen's marsh in Westminster. We saw him atop this perch quite frequently. 

Although he looks like he might collapse the house, a Great Blue weighs only 5 to 6 pounds. 

Most times when you see them flying, the heron's neck is in an S-shape, this improves its aerodynamics.

Here's a good shot of him all stretched out.

You can really get an idea of the length of those wings in this picture!

Although he looks like a flasher, this behavior is simply called "sunning". It was late afternoon, the sun was setting and he's gathering the last warm rays. Springtime in Vermont!

Sunday, June 3, 2012

Backyard Barred Owl

barred owl
   Also known as the "hoot owl", we have two barred owls in our neighborhood. We can hear the familiar "who cooks for you, who cooks for you all" hooting at night as well as in the daytime. Barred owls have many calls, including one sounding like raucous monkeys. The male's voice is said to be deeper and mellower than the female but I can't tell the difference.

is that a vole in your mouth?

   Even though this owl is well camouflaged, it seems whenever we're near, he silently glides away. It might have something to do with the fact that our hikes in the woods are accompanied by three rambunctious dogs who love to chase squirrels. 

  Owls have specialized feathers with fringes of varying softness the help muffle sound when they fly. Their broad wings and light bodies also make them nearly silent fliers, which helps them stalk prey more easily.

   This day we spotted him with a vole. A Barred Owl will use a perch, from where he dives upon its prey - meadow voles are his favorite, followed by shrews and deer mice. Others include rats, squirrels, young rabbits, bats, moles, opossums, mink, and weasels. Birds are taken occasionally, including woodpeckers, grouse, quail, jays, blackbirds, and pigeons. They also eats small fish, turtles, frogs, snakes, lizards, crayfish, scorpions, beetles, crickets, and grasshoppers.

   Owls have zygodactyl feet with two toes pointing forward and two toes pointing backward. This gives the birds a stronger, more powerful grip so they can be more effective predators. 
   Watching a predator eat its prey is not for the feint of heart. He'll eat every part of his catch and later regurgitate a pellet of indigestible material such as the bones and fur.

An owl has three eyelids: one for blinking, one for sleeping and one for keeping the eye clean and healthy. Not sure what one he's using here.

An owl's eyes are supported by bony eye sockets and they cannot turn their eyes. Instead, owls rotate their heads up to 270 degrees, but they cannot turn their heads all the way around. The barred owl is one of a few types who have dark brown eyes, most have yellow eyes.