Friday, September 30, 2016

American Goldfinches are turning color

Male Goldfinch molting for winter
You may have noticed that the yellow goldfinches in your yard aren't as vibrant as they were just a few weeks ago. That is nature's way of saying autumn has arrived and cold weather is not long off.

All birds molt but American Goldfinches do it in style. The brilliant lemon yellow that is so common in summer is now becoming a blotchy olive-yellow. In a few weeks, the birds will have completed their molting and the yellow of their feathers will be replaced by a drab olive-brown. Male goldfinches will become almost indistinguishable from the females, with the exception that the females will have a grayer cast to their olive-brown color.

Some goldfinches migrate south for the winter but most stay in our area. It's a good thing for the males to change color. With fewer leaves on the trees, the males become harder for predators to spot.

Goldfinches do not have the ability to change color in the same way a chameleon does to match its surroundings. For goldfinches, the change in color is triggered by hormonal changes affecting carotenoid pigments. Some researchers believe that the length of daylight or differences in the bird's diet may contribute to the hormonal changes.

The change in color isn't limited to their feathers. The bills of the both sexes also change color, from an orange yellow in summer to a dark bill in winter. The darker appearance is the result of melatonin deposition, possibly because of hormonal changes. The young have a dark bill even before they leave the nest.

After winter ends, male goldfinches replace their drab feathers with the lemon yellow that we enjoy seeing in summer. The brighter the male during breeding season in June, the greater he'll impress a female and mate.

Cold-weather goldfinches can be identified by their conical bill, pointed notched tails, wing bars and lack of streaking. They are acrobatic and active, often clinging to dried sunflowers, black-eyed susans or coneflowers well into the fall. 

Try this trick to attract goldfinches: Instead of cutting back your raggedy-looking coneflowers, let them stand so the seed cones can mature. Coneflowers are prized by goldfinches. It's not uncommon to see a goldfinch grasping onto a stem, often hanging upside down, to extract seeds from the cone. When the seeds disappear from the cone, then you can cut the coneflowers to the ground for winter.

Goldfinches are found mainly in weedy fields and floodplains or other overgrown areas where plants such as sunflower, aster and thistle are common. Of course, feeders will bring them to the backyards, where they shelter and nest in shrubs and trees.

The birds fly with a bouncy rollercoaster pattern, often calling while flying.

Goldfinches nest later in the summer than most other birds. They wait until mid- to late summer when milkweed, thistle and other plants have produced their fibrous seeds.

They choose to nest in maple, oak or other deciduous trees (or pine trees) about 30 feet above the ground. The nest is an open cut of rootlets woven so tightly that it can hold water. The female lashes the foundation to supporting branches and lines it with fluffy material taken from the same plants fro which the birds feed. It takes a female about six days to complete the nest. Clutch size is two to seven eggs; incubation lasts 12 to 14 days. The chicks hatch in another 11 to 17 days.

Goldfinches are strict vegetarians. Only inadvertently will they swallow an insect.

The best way to attract goldfinches to your backyard is to provide a nyjer seed feeder. These feeders are tube shaped with small ports sized to keep the seed from falling out. Fill the feeder with nyjer seed (which mistakenly is called "thistle seed") or with a "finch mix" that contains both nyjer and tiny fragments of sunflower seed. If you use the mix, don't be surprised to see an occasional Downy Woodpecker feeding from the feeder!

Goldfinches also will come to tube feeders filled with black oil sunflower seed.

The birds compete for food, and they put on a great show as they chase each other and vie for space on the feeder.

Monday, September 26, 2016

Lehigh Valley bird sightings for September 24

Philadelphia Vireo
While birders were scanning the skies last week for hawks, eagles and falcons, an extraordinary number of sightings of Philadelphia Vireos were reported throughout the Lehigh Valley region.

The Philadelphia Vireo is a migratory bird often mistaken at first glance by its common relative, the Red-eyed Vireo. The two species live in the same kind of habitat: deciduous trees such as aspen, willow, alder, ash and maple. But they don't get along very well. They've been known to fight for territory.


Despite its name, the Philadelphia Vireo is almost never seen in the Lehigh Valley except for an occasional sighting during migration in the spring and fall. The bird migrates mostly at night. It spends its days refueling for the flight across the Gulf of Mexico to wintering grounds in Central America, where it is found from the Yucatan Peninsula to Panama.


The Philadelphia Vireo breeds in Canada north of the Great Lakes, with the greatest concentrations found between Quebec and Saskatchewan. It nests in trees. The female produces three to five eggs. Both parents incubate the eggs, which hatch in about 14 days. The young leave the nest 12 to 14 days after hatching.



A comparison: Red-eyed Vireo
Adults are mainly olive-brown on the upper parts with yellow underparts and a gray crown. They have no wing bars and no eye ring but display dark eyes through the dark eyes and a white stripe just above them. 

The diet consists of mostly of caterpillars, moths, beetles, wasps, bees, ants, bugs and some spiders. It is a berry-eater in late summer and fall, when bayberry and dogwood fruit are available. The bird forages mostly in deciduous trees, flitting from branch to branch looking for insects. It often will hover from foliage or hang upside down to feast on insects located underneath twigs.


So where did the Philadelphia Vireo get its name? Other than migration time, the bird is rarely seen in the City of Brotherly Love. It turns out that ornithologist John Cassin collected a specimen of the bird in Philadelphia during the 1851 migration, hence the name. Birders of the era sometimes called it the Brotherly-love Vireo, according to Tennessee's Watchable Wildlife.


Populations of the Philadelphia Vireo appear to have increased between 1966 and 2014, the North American Breeding Survey reports.



Philadelphia Vireo
Regional sightings of the Philadelphia Vireo appear in Dave DeReamus's report for the Eastern PA Birdline, which is sponsored by the Lehigh Valley Audubon Society. The list covers the week ended September 24.

Pen Argyl, Northampton County

Gray-cheeked Thrush: 1 on September 20.

Jacobsburg State Park, Northampton County

Philadelphia Vireo: 2 on September 16 and 1 on September 22.

Williams Township, Northampton County

Connecticut Warbler: 1 on September 23.

Monocacy Nature Center, Northampton County

Philadelphia Vireo, 1 on September 22.

Little Gap, Northampton County

Ruffed Grouse, 1 on September 18.
Philadelphia Vireo, 1 on September 16.


Little Gap, Carbon County
(at the Blue Mountain Ski Resort)
Philadelphia Vireo, 1 on September 18.

Bake Oven Knob, Lehigh County

Osprey, 34 on September 17.
Bald Eagle, 12 on September 17 and 10 on September 20.
Broad-winged Hawk, 1,901 on September 20 and 519 on September 22.
Peregrine Falcon, 2 on September 20 and September 22.
Philadelphia Vireo, 1 on September 16 and September 23.

Long Swamp Township, Berks County

Mississippi Kite, 1 on September 22 (fly-by).

Green Lane Reservoir, Montgomery County

(at the Church Road area)
Black-crowned Night Heron, 1 on September 19.
Snowy Egret, 1 from September 19 through September 22.
American Golden-Plover, 2 on September 22.
Stilt Sandpiper, 1 on September 17 and 2 from September 19 to September 21.
Sanderling, 2 on September 19 and 1 on September 20.

Peace Valley Park, Bucks County

Lesser Black-backed Gull, approximately 50 on September 17.
Forster's Tern, 2 on September 16.
Philadelphia Vireo, 1 on September 17.
Gray-cheeked Thrush, 1 on September 17.

Red-breasted Nuthatches continue to be reported from several sites last week.


To report bird sightings to Dave DeReamus, send an e-mail to becard.com with the word "Birdline" in the subject heading.


Friday, September 23, 2016

Broad-winged Hawk
This weekend is approaching the peak time for viewing the migration of raptors along the mountain ridges of the Lehigh Valley. The weather will be fine for viewing hawks, eagles, ospreys and other raptors that congregate for the autumn migration.

Broad-winged Hawks are the most numerous species reported thus far, being the first raptors to migrate. These small hawks are not often noticed during the breeding season. They usually nest near forest openings and bodies of water, far from humans. But toward autumn, hundreds of thousands fly to their wintering grounds in Central and South America.


If you'd like to enjoy seeing the raptor migration, your best chances of viewing include Little Gap Hawk Watch, Lehigh Furnace Gap and, of course, Bake Oven Knob. The Knob is a popular site because the birds soar above the Kittatiny Ridge, some species coming within easy eyesight.


But keep your eyes to the sky no matter where you are. You never can tell when you'll see one of these remarkable creatures!


Last weekend provided bird watchers with a variety of raptors in many locations. These are the birds that were spotted:


Emrick Boulevard Shopping Center, Northampton County

Red-tailed Hawk, 2 on September 18.
American Kestrel, 1 on September 18.

Minsi Lake, Northampton County

Bald Eagle, 1 on September 18.

Little Gap Hawk Watch, Northampton County

Osprey, 39 on September 17.
Northern Harrier, 5 on September 17.
Sharp-shinned Hawk, 36 on September 17.
Cooper's Hawk, 5 on September 17.
Bald Eagle, 32 on September 17.
Broad-winged Hawk, 172 on September 17.
Red-tailed Hawk, 4 on September 17.
American Kestrel, 1 on September 17.
Merlin, 1 on September 17.


Broad-winged Hawk
Martins Creek Environmental Preserve, Northampton County
Osprey, 5 on September 17.
American Kestrel, 6 on September 17.
Also seen: Cooper's and Red-tailed hawks.

Jordan Lutheran Church, Lehigh County

Merlin, 1 perched near the parking lot, on September 18.

Haafsville, Lehigh County

Red-tailed Hawk, 1 on September 17.

Pennsylvania Turnpike

(at the Allentown rest stop on the Northeast Extension)
Cooper's Hawk, 1 on September 17.
Red-tailed Hawk, 1 on September 17.

Memorial Road, Lehigh County

Bald Eagle, 1 on September 17.

Lehigh Furnace Gap, Lehigh County

Osprey, 1 on September 17.
Sharp-shinned Hawk, 1 on September 17.
Bald Eagle, 1 on September 17.
Broad-winged Hawk, 22 on September 17.
Red-tailed Hawk, 1 on September 17.

Bake Oven Knob, Lehigh County

Osprey, 45 on September 17.
Sharp-shinned Hawk, 18 on September 17.
Cooper's Hawk, 2 on September 17.
Bald Eagle, 20 on September 17.
Broad-winged Hawk, 270 on September 17.
Red-tailed Hawk, 3 on September 17.
American Kestrel, 4 on September 17.

Trexler Nature Preserve, Lehigh County

Sharp-shinned Hawk, 1 on September 17.
Red-tailed Hawk, 3 on September 17.
American Kestrel, 1 on September 17.


Weather forecast for this weekend:




If you miss this weekend's viewing, don't worry. The migration will continue for a couple more weeks as late-departing species pass through the Lehigh Valley.





Hawk Watch trip planned for Saturday

Sharp-shinned Hawk
The Lehigh Valley Audubon Society is sponsoring a trip to Scott's Mountain Hawk Watch on Saturday, September 24. You will likely see Sharp-shinned Hawks and Cooper's Hawks as they migrate southward along the ridge line. Merlins and Peregrine Falcons might also be seen.

Meet at 7:30 a.m. at the Park and Ride lot at Route 33 and William Penn Highway in Bethlehem Township. From there, you'll carpool to Scott's Mountain. 

Bring a snack if you choose. If you have a spotting scope, bring it. If you don't, you can always borrow a peek through someone else's scope. A parking lot is adjacent to the Hawk Watch, so there will be minimal walking. Dave DeReamus will lead the trip.



Tuesday, September 20, 2016

Lehigh Valley bird sightings for September 17

Orange-crowned Warbler
Here are the Lehigh Valley bird sightings for the week ended September 17. The list was compiled by Dave DeReamus, of the Eastern PA Birdline, which is sponsored by the Lehigh Valley Audubon Society.

Little Gap, Carbon County
(at the Blue Mountain Ski Resort)
Orange-crowned Warbler, 1 on September 15.

Bake Oven Knob, Lehigh County
Osprey, 30 on September 13.
Bald Eagle, 10 on September 11.
Broad-winged Hawk, 526 on September 13; 1,303 on September 16.
Merlin, 29 on September 11.
Also seen: Common Raven.

Green Lane Reservoir, Montgomery County
(at the Church Road area)
American Golden-Plover, 1 on September 10.
Stilt Sandpiper, 3 on September 11.
Sanderling, 1 on September 9 and 10.
White-rumped Sandpiper, 1 on September 10, 3 on September 11 and 12, and 1 on September 14.

Peace Valley Park, Bucks County
Peregrine Falcon, 1 on September 9 and September 11.
Red-headed Woodpecker, 1 on September 15.

Red-breasted Nuthatches continue to be reported from several sites this past week.

To report bird sightings to Dave DeReamus, send an e-mail to becard@rcn.com with the word "Birdline" in the subject heading.

Sunday, September 4, 2016

Lehigh Valley bird sightings for week of September 2

Laughing Gulls
Here are the Lehigh Valley bird sightings for the week ended September 2. The list was compiled by Dave DeReamus, of the Eastern PA Birdline, which is sponsored by the Lehigh Valley Audubon Society.

Williams Township, Northampton County
Dickcissel, 1 on August 26 and August 27 (first-year male).

Leaser Lake, Lehigh County
Black-crowned Night-Heron, 2 on August 30.

Bake Oven Knob, Lehigh County
Osprey, 29 on August 28.
Bald Eagle, 7 on August 28.
Also seen: Common Raven and Red-breasted Nuthatch.

Green Lane Reservoir, Montgomery County
(at the Church Road area)
Snowy Egret, 1 on August 27, August 31 and September 1.
Little Blue Heron, up to 2 to at least August 30.
Stilt Sandpiper, 1 on August 27; 3 on August 29, August 31 and September 1.

Deep Creek/Knight Lake, Montgomery County
Glossy Ibis, 1 to at least August 29.

Peace Valley Park, Bucks County
Laughing Gull, 1 on August 27.
Yellow-bellied Flycatcher, 1 on August 27.
Also seen: Red-breasted Nuthatch.

To report bird sightings to Dave DeReamus, send an e-mail to becard@rcn.com with the word "Birdline" in the subject heading.

Saturday, September 3, 2016

Who knew?

The Kiwi, the only wingless bird
A few thoughts about birds, bird behavior and the language of birds …

When a group of hawks rides a thermal, the birds seem to swirl upward like the steam rising from a boiling kettle. That's why a group of hawks is called a "kettle."


In winter, the Ptarmigan in Alaska grows special feathers on the tops and bottoms of its feet. These work like snowshoes, allowing the bird to walk across the surface of the snow.

Many birds line nests with feathers to help warm the eggs. It is from this practice that we get the phrase "to feather one's nest," which means to stock up on goodies for oneself, often at someone else's expense.

The natives of New Hebrides, a small group of western Pacific islands, used feathers for money. One honeyeater feather was worth one pig or two wives.

Overheated birds don't sweat but some pant. Herons, for example, rapidly vibrate their throats to increase evaporation. Ornithologists call this gular fluttering.

Although there are 46 species of flightless birds, the Kiwi of New Zealand is the only wingless bird.

Migrating ducks and geese often fly in V-shaped formations. Each bird flies in the upwash of its neighbor's beating wings. This enables the bird to fly 70 percent farther than on its own.

Flamingoes strain food out of their water through horny plates inside their beaks. The Lesser Flamingo has a filter that can trap single cells.

Birds have enormous eyes. Our eyes make up less than 1 percent of the weight of our head. Owls have the biggest eyes relative to the size of their heads. If we were an owl, our eyes would weigh several pounds.

Greek legend says that just before the Mute Swan dies, it bursts into a beautiful song. Today, any artist's last work is called the "swan song."

Birds sing or squawk with a syrinx, stretchy membranes located at the bottom of the windpipe. Birds can sing with their mouths full; they also can sing two different notes at the same time. The two sides of syrinx use air from a different lung.