Saturday, February 21, 2015

The Raven: Nesting in Philadelphia for the First Time?

Few birds are more intriguing than the Common Raven. Big, broad, and wholly black, the wedge-tailed raven is impressive, at times imposing, and always fascinating.
Common Raven in Nome, Alaska June 21st, 2010
(Photo by G. Armistead)

With gurgles, croaks, and screams, they have an incredible repertoire of sounds, and they are superb aerialists. Often seen soaring like an eagle, other times they roll while on the wing, somersault, or slip sideways straight down out of the air. It is the largest songbird (passerine) in the world, and one of the most intelligent animals in existence, plainly smarter than any Dallas Cowboys fan, for instance. (Though admittedly, that is not saying much).

"Grip" the Raven. Owned by Charles Dickens, he inspired Poe's poem.
Ravens can eat almost anything, and so it's not surprising that it is one of the most widespread birds in the world. Common across much of Eurasia and North America, this is one of the few birds that can withstand winter in the high arctic, remaining there even during the darkest, coldest parts of the year. Found from the arctic circle south into Central America, it is common throughout most of Canada, and in the Lower 48 is throughout most of the American West, but is absent the Mid-West, and in the East it was historically confined to the Appalachians. But Ravens have been on the uptick of late, expanding their range and increasing, with more and more sightings and nests away from the Appalachians, and in the piedmont and the coastal plain.

Here in Philadelphia, the history of the raven is mostly related to the famous poem by Edgar Allen Poe. The Free Library of Philadelphia has a mounted raven specimen that is purported to be the very same one owned by Charles Dickens that inspired Poe to write the poem The Raven. Otherwise, the wild Common Raven's history here is one of absence.
Two Common Ravens discovered on Feb. 1st on north Delaware Ave.
(Photo by Holly Merker)

The eBird database shows zero records before 2000 (though there surely were a few), but a number of reports since 2005. Most sightings have come from South Philly (Heinz NWR or nearby) or in Northeast Philly. On February 1st, 2015 Holly Merker and Devich Farbotnik visited the Northeast Water Pollution Control Plant, well known for its isolated population of over-wintering Northern Rough-winged Swallows. They discovered not one, but two ravens, exhibiting behavior that could be interpreted as pair bonding, and suggested these birds might stick around to nest. On February 21st, these birds are still present. Keith Russell of Audubon Pennsylvania, the authority on the history of Philadelphia's birds, notes that the species has never before been recorded nesting within the city limits. And according to Russell, Philadelphia has not added a new species of breeding bird here since the Black Vulture was found nesting in 2006.

The site where these ravens are hanging around is right along the Delaware river, and no nest has been located yet. It's possible they are not nesting or have a nest just across the river in New Jersey. But their behavior seems to indicate that they will nest, and most of their activity seems centered on the Philadelphia side of the Delaware. Ravens begin nesting relatively early, often in February, and usually have eggs in March. As we get into April and early May, we will have to keep an eye out to see if we can observe these 2 birds carrying food. Eventually we may see fledglings! Time will tell, but for now it is awful nice to have such a fascinating bird frequenting the area. 
Common Raven over Delaware Avenue on Feb. 21, 2015. Compared to the abundant crows present, note the raven's long wedge-shaped tail, large size, long pointed wings, and heavy bill. (Photo by G. Armistead)