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All posts for the month August, 2014

By Joe Sebastiani, Seasonal Program Team Leader

One of my summer camp routines is to get outside and take photos of camp activities on a regular basis.  On August 8th, I was out on a beautiful day and stumbled across a small flock of Chickadees and Titmice.  Since early August is the beginning of songbird migration, and migrant warblers usually hang around Chickadee and Titmouse flocks, I paused for a look.  Soon, I got a glimpse of a yellow-bellied bird flit through the trees.  A warbler!  I relocated the bird quickly and what I saw did not compute.  I wasn’t familiar with this bird, but it registered in my mind from looking at bird field guides since I was young.

When I realized what I was seeing, I was determined to photograph this bird, which turned out to be a Lawrence's Warbler, which is a rare hybrid in the Blue-winged and Golden-winged Warbler species complex.

When I realized what I was seeing, I was determined to photograph this bird, which turned out to be a Lawrence’s Warbler, which is a rare hybrid in the Blue-winged and Golden-winged Warbler species complex.  Photo by Joe Sebastiani

This yellow-bellied warbler had a faint black throat and a faint black mask around the eye.  It had white wing bars, and white under the tail.  It also had a golden-yellow forehead.  I was pretty sure I had found a Lawrence’s Warbler, and after looking it up later, confirmed it.  Lawrence’s Warbler is not a distinct species, but rather a rare hybrid that is produced by one of several parent combinations.  It is a complex story, but Blue-winged Warblers and Golden-winged Warblers are very closely related.  They hybridize freely, and normally produce a hybrid called a Brewster’s Warbler, which is white bellied with a black eye stripe.  A Lawrence’s Warbler is product of a more complicated pairing summarized this way by the Peterson Field Guide to Warblers, “Lawrence’s Warbler is produced by pairings between a “Brewster’s (existing hybrid) and a Golden-winged Warbler that carries the recessive gene for yellow underpart color; or a pairing between a “Brewster’s and a Blue-winged Warbler that carries the recessive gene for the black-mask and throat; or a pairing with two Golden-winged Warbler carrying the recessive gene for yellow underpart color (1 in 16 chance); or a pairing of two hybrid “Brewster’s Warblers”.

The seldom seen Lawrence's Warbler is a product of a complicated hybrid genetics, and has only been documented in Delaware about 4 times.  It appears that this Ashland bird is the 5th documented record.

The seldom seen Lawrence’s Warbler is a product of a complicated hybrid genetics, and has only been documented in Delaware about 4 times. It appears that this Ashland bird is the 5th documented record. Photo by Joe Sebastiani

Unfortunately, populations of the straight-species Golden-winged Warbler, which nests in the Appalachian Mountains and around the Great Lakes States, are losing ground.  They are disappearing due to loss of their early successional habitat requirements for nesting, but to make matters worse, Blue-winged Warblers are swamping their genetics by hybridizing with them.  The result has been a steady decline in Golden-winged Warblers.  Sightings like the Lawrence’s Warbler I found at Ashland, are a reminder that species divisions can be a bit blurry sometimes, and the notion of a species doesn’t always fit into our neat and tidy human definition, even for two birds that are distinctly different in appearance.

In Delaware there are records of  this hybrid from 1932, 1979, 2006, and possibly another record that I do not have a date for.  That makes this the 4th or 5th record of this hybrid to be found in Delaware.  This rare and unusual bird was exciting to find and a challenge to photograph.  You never know what you will find on a nature walk, and any average day can hold the biggest surprises.

If you are interested, there is a Fall Warbler Preparation program happening at Ashland Nature Center this Saturday, 1-4pm.  It is free for members of the Delaware Nature Society and $5 for non-members.  Please call 302-239-2334 email dnsinfo@delawarenaturesociety.org if you would like to attend.

By Evan Gruber, Coverdale Farm Steward

There are two new additions to the herd at Coverdale Farm, calves from two local farms have arrived for the next 6 -8 weeks and are being kept in the newly constructed calf yard. A brown Jersey calf is on loan from Woodside Farm Creamery in Hockessin Delaware, and a black and white Holstein calf is from Old Stone Farm in Lewisville Pennsylvania. Both are bull calves that will eventually be castrated (which make them steer) and raised for meat. They are each fed two gallons of milk per day, and in their time here they will drink around 115 gallons each! They also have free choice grain and hay to eat once they are old enough for solid food.

Jersey Calf

Jersey Calf.  Image by Derek Stoner.

 

Holstein Calf

Holstein Calf.  Image by Derek Stoner

 

I would also like to introduce the newest members of our land management crew, Boer goats! The breed is originally from Africa, and is primarily used for meat production. These particular goats come from a background where they were handled quite a bit, so they are very comfortable around people and enjoy their head getting scratched, or to be fed some clover from the other side of the fence. Their diet consists of whatever weeds are growing in the pasture, they get no extra grain or feed. A goat’s eating habits are more similar to a deer than to a sheep or cow, they prefer woody plants and broadleaf weeds which makes them perfect for their main purpose on the farm, which is keeping the cow pasture weed free. A cow’s diet is typically around 90% grasses and clovers, and 10% brush, a goats diet is around 30%grasses and 70% brush, this makes them perfect for eating anything the cows miss. This helps the farm staff because we have to mow less often, as well as reducing how often we need to string trim under the fences.

New Coverdale Staff Member

New Coverdale Staff Member.  Image by Derek Stoner

Come visit the new members of the farm on a Farm Fun Day; Wednesday afternoons 12:00 – 2:30pm, and every 3rd Saturday 8:00 – 11:00am.

Attend a Farm Fun Day and see who is new on the farm!

Attend a Farm Fun Day and see who is new on the farm!