Archives

All posts for the month November, 2009

By Jason Beale, Manager, Abbott’s Mill Nature Center
Three days of steady rain and high winds are still making their mark at Abbott’s Mill Nature Center.  The Abbott’s Pond spillway is working overtime with all of the water rushing through.  Memorial Day rains had already washed out parts of the dam, undermining the bridge on Abbott’s Pond Road, which has been closed since then.
Abbott's Pond spillway working overtime

Abbott's Pond spillway working overtime

The generally slow and meandering Johnson’s Branch has morphed into Johnson’s Swamp, flooding all low lying areas.  While floods and storm surges may be viewed as unpredictable disasters, marine and freshwater edge habitats are inherently dynamic in nature and human land use often influences the severity of these events through increased run-off, reduced percolation, and expensive infrastructure located in these areas.  

Together again: the confluence of Johnson's Branch (top) and the Mill Tail Race (bottom)

Together again: the confluence of Johnson's Branch (top) and the Mill Tail Race (bottom)

This natural process has shaped southern Delaware’s streamside forests for thousands of years.  The periodic flooding of these areas made them difficult to farm or build on, which is the reason that many of these forests still line the floodplains of the region.  Indicator soils, plants, and animals in these areas are adapted to survive and thrive in this dynamic habitat.  The waters deposit rich soil and water-borne seeds, which in turn supports new plant growth, slowly building up the land.  Trees, uprooted by the high waters or wind, provide a damming effect.  All of these events contribute to the alteration of the stream channel. 

Johnson's Swamp?  The bright leaves of winterberry and fringe-tree, two denizens of the swamp forest at Abbott's Mill.

Johnson's Swamp? The bright leaves of winterberry and fringe-tree, two denizens of the swamp forest at Abbott's Mill, are visible at the typical stream boundary.

Looking at old tax maps, one can track these changes.  In fact, Ainsworth Abbott, the last miller, was in constant dispute with his neighbors over the ownership of the land and the stream’s inability to adhere to human-imposed boundaries.
Abbott's Mill outflow.  Note the submerged wall to the right of the bricks

Abbott's Mill outflow. Note the submerged wall to the left of the bricks.

Take the time to look closer at the plants and animals that live along Delaware’s waterways and discover the unique adaptations that allow them to persist through floods and the other extreme, droughts.

The Eagles at Conowingo trip has been rescheduled to Friday, November 20th, 8am to noon.  If you would like to reserve a spot, visit www.delawarenaturesociety.org or call (302) 239-2334 ext. 134.

By Joe Sebastiani, Members Program Team Leader

Last week, I asked you to identify a bird in a photo that I took in September.  I gave you four possible correct choices, all of which can be found at Ashland Nature Center in September.  Here is the quiz bird…

What species of bird is this?  It was photographed outside my office window at Ashland Nature Center in September.  Photo by Joe Sebastiani

What species of bird is this? It was photographed outside my office window at Ashland Nature Center in September. Photo by Joe Sebastiani

The other three choices, which were incorrect, are pictured below. 
A Common Yellowthroat in winter plumage.  Photo by Joe Sebastiani

A Common Yellowthroat in winter plumage. Photo by Joe Sebastiani

Common Yellowthroat was a good guess, because the quiz bird has a yellow throat, but there are many differences between this and our quiz bird.  The Common Yellowthroat pictured above has yellow going way down onto the belly and if you looked in a bird book, the Yellowthroat has no wing bars.  The quiz bird has wing bars, which are the white lines on the wing.

A Red-eyed Vireo, by Derek Stoner.

A Red-eyed Vireo, by Derek Stoner.

Red-eyed Vireo was a guessed by very few of you.  This vireo has no wing bars , plus there is very little yellow on the throat.  Also, the wings are green, not blue, as in our quiz bird.
A female Orchard Oriole, by Joe Sebastiani

A female Orchard Oriole, by Joe Sebastiani

Another good guess was the Orchard Oriole, at least a female, which is pictured above.  (Males are brick red).  Female Orchard Orioles have wing bars, just like our quiz bird.  There is also plenty of yellow on this bird…but a little too much yellow.  Our quiz bird just has yellow on the throat.  Orchard Orioles are very rare in Delaware in September, but not out of the realm of possibility

What is our quiz bird?  A Northern Parula.   Northern Parulas are small warblers that migrate through Delaware in Spring and Fall.  A few stay to breed in scattered wooded areas around the state, including a few pair in the Red Clay Valley where Ashland Nature Center is located.  Hopefully you had fun with the quiz and learned a little about our local birds.

By Derek Stoner, Family Programs Coordinator

A young male Rufous Hummingbird sips from a nectar feeder in Avondale, PA.  October 2009 photo by Kathy Weaver.

A young female Rufous Hummingbird sips from a nectar feeder in Avondale, PA. October 2009 photo by Kathy Weaver.

The 30-degree weather this past weekend did not faze the young female Rufous Hummingbird visiting a backyard in Avondale, PA.  Weighing in at 3 grams and possessing a stove-hot metabolism with a heart beat of 600 beats per minute, this tiny bird is thriving on the nectar of late-blooming flowers, tiny insects and spiders, and a generous suppply of sugar water offered by the owners of a vibrant backyard habitat.  

An immature male Rufous Hummingbird perches on a feeder in Dover, DE, on January 22, 2009.

A young male Rufous Hummingbird perches on a feeder in Dover, DE. Notice the spider silk caught in his beak, as spiders are a key dietary component of hummingbirds in winter. January 22, 2009 photo by Derek Stoner.

How do they survive the cold?  These hummingbirds have the unique ability to “turn down the thermostat” so to speak, through a process called torpor.  As the hummingbird settles in for the night to sleep, their heartbeat slows to less than 100 beats per minute.  The torpid state has been described as “suspended animation” as the bird enters a zone of semi-consciousness.
A Rufous hummingbird perches on branch on January 22, 2009.  Photo by Derek Stoner.

A Rufous Hummingbird perches on branch on January 22, 2009. This bird survived overnight temperatures of 5 degrees! Photo by Derek Stoner.

The obvious question is: what is this hummingbird doing here right now?  Is he lost?  Is he going to survive the cold winter?  Fortunately, scientists(bird banders in particular) in recent years have started to unravel this story of how hummingbirds are spending the winter on the East Coast.  There are several bird banders in the region who are working to solve this mystery.  Well-known author and bird bander Scott Weidensaul’s website has an excellent discussion of this research:  http://www.scottweidensaul.com/research_hummingbirds.html
A young male Rufous Hummingbird stretches his wings.  December 1, 2006 photo by Jim White.

A Rufous Hummingbird stretches his wings. December 1, 2006 photo by Jim White.

The Rufous Hummingbird is the most widely-distributed hummingbird in North America, breeding as far north as Alaska.  The Rufous has been recorded in every US state except Hawaii, and undertakes the longest migration of any North American hummingbird.  The majority of Rufous Hummingbirds spend the winter in Mexico and Central America, but new evidence points to the fact that more of these birds are wintering in the eastern United States than we may realize. 
A Rufous Hummingbird visitng Jim White's feeder in Winter 2006.  Notice the silver band on the bird's leg!  Photo by Jim White.

A Rufous Hummingbird visiting Jim White's feeder in Winter 2006. Notice the silver band on the bird's leg! Photo by Jim White.

Other species of hummingbird are also being documented wintering along the East Coast, from Calliope to Allen’s to Broad-billed Hummingbirds.  Scientists and birders alike are re-thinking their ideas about hummingbird migration and the selection of wintering habitat.
There is a lot more to learn about these amazing hummingbirds.   Stay tuned for part two of this story! 

By Joe Sebastiani, Members Program Team Leader

It is time to sharpen your naturalist skills again by taking another quiz.  This photograph was taken by me from my office window at Ashland Nature Center in September.  If you aren’t familiar with this bird, take a look in a bird book or on the web to see if you can figure out what species it is.  Click on your guess in the multiple choice polling box below.  I will post the answer next week.

What species of bird is this?  It was photographed outside my office window at Ashland Nature Center in September.

What species of bird is this? It was photographed outside my office window at Ashland Nature Center in September.

Upcoming birding trips with the Delaware Nature Society include Waterfowl Watch at the Dupont Environmental Education Center on November 8 and Hawk Mountain – Big Raptors of the Late Season on November 11.  View our website, www.delawarenaturesociety.org for more information or to register.