Tuesday, May 15, 2012

A New Home for Chimney Swifts at the John James Audubon Center at Mill Grove

On your most recent visit to the John James Audubon Center at Mill Grove, you may have noticed the tall, white structure pictured above located by the new parking lot to the cottage. Though it may look a little strange, this structure plays an important part for conservation. It's the new chimney swift tower, built as an Eagle Scout project by Mark Frederick and designed to provide a place for chimney swifts to roost and nest.

Chimney swifts are known in the birding community as “flying cigars” that buzz our cities and waterways. They arrive in our area in late April and can be observed flitting through our skies catching insects on the wing. It is presumed that before European settlers, these delightful birds nested and roosted in old hollowed out trees. When the Europeans brought with them the architectural structure of the chimney, chimney swifts found these stone “hollow trees” perfect for nesting and roosting. Over time they became dependent on these chimneys and, in turn, became more urban. Today chimney swifts are in decline due to changes in chimney management. Chimneys are increasingly being capped to prevent “critters” access and chimney swifts are finding fewer sites to meet their needs. That is why the installation of chimney swift towers is so important. By placing these towers in correct locations we are trying offset the decline of chimney swifts by providing new nesting and roosting sites.

Chimney swifts are fascinating birds that spend a great deal of the day on the wing and spend their evenings attached to the interior wall of a chimney or other dark crevice. They are insectivores and capture their prey in mid-air. Chimney swifts winter in South America along the upper Amazon Basin of Brazil, Peru, Columbia, and Ecuador, and arrive in Southeastern Pennsylvania in late April and early May for breeding. Chimney swifts build a half cup structure on the interior wall of the chimney with small sticks that are glued together with sticky saliva. Both parents build the nest where the female lays  4-5 eggs. Incubation is shared by both parents, and starts after the 2nd to last egg is laid. The eggs hatch after about 19 days and the youngsters are born naked and blind. Once the eggs hatch, the parents get busy catching insects to feed the babies. After two weeks the baby birds may move out of the nest and attach to the interior walls of the chimney. After 30 days they are ready to fledge and directly fly out of the chimney. One fascinating aspect of Chimney Swifts is that only one breeding pair may nest in a chimney with numerous other roosting swifts. Some of the non-breeding birds may help feed the breeding pairs’ young. After the young fledge they catch their own insects and can be seen flying with the other adult birds. A trick you can use to tell adults from juveniles in summer is to look for missing feathers at the first or second primary feather on the wing (primaries are the last 10 feathers at the end of the wing; the ones in question are closest to the bird’s body). Adults start their molt after breeding while recently fledged birds are not missing any flight feathers.

The John James Audubon Center at Mill Grove and the Valley Forge Audubon Society would like to thank Mark Frederick for taking on this challenging project. We hope the Chimney Swift Tower will provide a nesting and roosting site for many years to come.

You can read more about chimney swifts at allaboutbirds.org or at chimneyswifts.org

Sunday, May 13, 2012

Field Report: International Migratory Bird Day Bird-a-thon at the John James Audubon Center at Mill Grove, May 12, 2012

Valley Forge Audubon Society celebrated International Migratory Bird Day at the John James Audubon Center at Mill Grove with a bird-a-thon. Vincent Smith, Joe Hudson, Dan Sullivan, and Rob Evans searched the grounds of the historic property and wildlife sanctuary looking for birds and raising money for VFAS. The event included bird walks open to the public, and four other birders joined them. Over the course of four hours, a total of 62 bird species were spotted. The complete list of birds follows this post.

Some of the birds seen, such as Magnolia Warbler, Blackpoll Warbler, and Swainson's Thrush, breed north of our area and are only seen here for a few weeks in May as they migrate to their nesting grounds, and then again in the fall when they return south to their wintering grounds. In fact, both Blackpoll Warblers and Swainson's Thrushes make incredible, long-distance migratory journeys from South America to the forests of Canada and back every year. International Migratory Bird Day highlights the important role conservation plays in the lives of these birds. On such long, arduous journeys, birds need safe places to rest and feed on their way to their breeding grounds and back. Suitable habitat with protection and a good food supply is critical for these birds to survive migration.

It also goes without saying that birds need a safe place to breed as well. Chimney Swifts, Great-crested Flycatchers, Tree Swallows, Barn Swallows, Northern Rough-winged Swallows, Northern Parulas, Scarlet Tanagers, Baltimore Orioles, and Orchard Orioles are all examples of birds that return to our area each spring to breed and then leave in the fall after their next generation have fledged. Again healthy habitat is needed to provide these birds and their young with shelter, a place to nest, and enough food for them and their new nestlings.

So our conservation areas need to contain enough healthy habitat to support migratory birds that use it as a rest stop on longer migrations, migratory birds that come in the spring to breed, and our native birds, such as Cooper's Hawks, Red-bellied Woodpeckers, Blue Jays, Carolina Chickadees, and Northern Cardinals, that live in the area throughout the year. With 62 species of birds observed at Mill Grove in four hours, you can see how diverse healthy habitat can be and the need to conserve that habitat and keep it healthy.

Here's the complete list of birds observed:

Canada Goose  12
Wood Duck  8 (Female with 7 fledglings)
Mallard  5
Common Merganser  1, These birds have started nesting in our area over the last 2 years.
Double-crested Cormorant  2
Great Blue Heron  2
Turkey Vulture  3
Osprey  1
Cooper's Hawk  1
Red-tailed Hawk  2
Mourning Dove  1
Chimney Swift  8
Ruby-throated Hummingbird  1
Belted Kingfisher  2
Red-bellied Woodpecker  5
Downy Woodpecker  4
Hairy Woodpecker  1
Northern Flicker  2
Eastern Phoebe  3
Great Crested Flycatcher  6
Warbling Vireo  2
Red-eyed Vireo  8
Blue Jay  8
American Crow  4
Fish Crow  1
Northern Rough-winged Swallow  2
Tree Swallow  9
Barn Swallow  6
Carolina Chickadee  6
Tufted Titmouse  10
White-breasted Nuthatch  3
Carolina Wren  2
House Wren  7
Eastern Bluebird  2
Swainson's Thrush  2
Wood Thrush  8
American Robin  9
Gray Catbird  15
Northern Mockingbird  1
European Starling  1
Cedar Waxwing  6
Black-and-white Warbler  1
Common Yellowthroat  3
Northern Parula  1
Magnolia Warbler  1
Yellow Warbler  2
Blackpoll Warbler  1
Black-throated Blue Warbler  1
Yellow-rumped Warbler  4
Eastern Towhee  2
Chipping Sparrow  5
Scarlet Tanager  2
Northern Cardinal  7
Rose-breasted Grosbeak  1
Indigo Bunting  5
Red-winged Blackbird  6
Common Grackle  11
Brown-headed Cowbird  2
Orchard Oriole  2
Baltimore Oriole  5
House Finch  3
American Goldfinch  5

Thursday, May 10, 2012

Field Report: Black Rock Sanctuary, May 5, 2012

Spring migration was in full effect this past Saturday at Black Rock Sanctuary where Vince Smith lead a bird walk that saw 53 species of birds, including such notable migrants as Green Heron, Great-crested Flycatcher, Brown Thrasher, Ovenbird, Black-and-white Warbler, Common Yellowthroat, American Redstart, Magnolia Warbler, Yellow Warbler, Chestnut-sided Warbler, Yellow-rumped Warbler, Baltimore Oriole, Orchard Oriole, and Rose-breasted Grosbeak. The complete list, as submitted to eBird follows:

Canada Goose  9
Mallard  3
Double-crested Cormorant  14
Green Heron  1
Black Vulture  1
Turkey Vulture  5
Mourning Dove  3
Chimney Swift  3
Red-bellied Woodpecker  3
Downy Woodpecker  2
Northern Flicker  4
Pileated Woodpecker  1
Great Crested Flycatcher  1
Warbling Vireo  5
Blue Jay  8
American Crow  4
Fish Crow  1
Northern Rough-winged Swallow  3
Tree Swallow  6
Barn Swallow  2
Carolina Chickadee  3
Tufted Titmouse  1
Carolina Wren  2
House Wren  2
Blue-gray Gnatcatcher  2
Eastern Bluebird  2
Wood Thrush  2
American Robin  5
Gray Catbird  10
Northern Mockingbird  1
Brown Thrasher  2
European Starling  5
Ovenbird  1
Black-and-white Warbler  1
Common Yellowthroat  3
American Redstart  1
Magnolia Warbler  1
Yellow Warbler  3
Chestnut-sided Warbler  1
Yellow-rumped Warbler  12
Eastern Towhee  1
Chipping Sparrow  1
Field Sparrow  3
Song Sparrow  2
White-throated Sparrow  4
Northern Cardinal  4
Rose-breasted Grosbeak  1
Red-winged Blackbird  5
Common Grackle  12
Brown-headed Cowbird  6
Orchard Oriole  3
Baltimore Oriole  4
American Goldfinch  1