More razorbills in Florida than ever

From 10,000 Birds blog:

The Razorbill Invasion of Florida

By Carlos • December 27, 2012

Razorbills (Alca torda) have invaded the coastal waters of Florida on an unprecedented scale this December of 2012. To put this invasion into perspective, there were only 14 documented records of Razorbill for the entire state before December 2012. This invasion has produced several documented sightings of flocks with well over a hundred individuals! The first sighting was of an individual seen and photographed right off the pier at Boynton Inlet on December 9, 2012. Many state listers immediately chased it even though the bird was very mobile and did not offer good looks for most who tried.

On December 11, 2012, an observer saw one at Government Cut in Miami-Dade right off the pier which was quickly followed by a sighting of three birds off Singer Island in Palm Beach, two birds filmed off Fort Lauderdale, and another bird photographed off Crandon Beach in Key Biscayne — already an unprecedented number of records. However, the true scope of the irruption was not apparent until people started chartering fishing boats to explore the waters just offshore where they were greeted by flocks of hundreds of Razorbills!

Listservs across the state suddenly lit up with posts about where and how many of these alcids were being seen, with records streaming in from such unlikely places as Dry Tortugas National Park, Key West, Fort de Soto, and as far west as Pensacola — there had been only one previous record of this species in the Gulf of Mexico before 2012.

Razorbills primarily feed on capelin, sandlance, herring, and other small fish in the productive waters of the cold North Atlantic, with large numbers wintering in the Gulf of Maine and the Bay of Fundy in the extreme northeastern United States and maritime provinces of Canada.

There is a reason why birds (and mammals and large, predatory sharks) like alcids, albatrosses, penguins, and other seabirds are restricted to the poles or areas of cold water upwellings — tropical waters lack the ability to hold onto as much oxygen as colder water. Also, tropical waters lack the dynamics for significant upwellings of cold, nutrient rich water to reach the surface and feed the extreme density of plankton that feed the vast schools of fish these birds rely upon. Why have these birds decided to fly so far south of their normal wintering range, and is it somehow connected to the fact that nearly all birds that have been documented are first year birds?

Sea surface temperatures off of New England and Nova Scotia have been unseasonably warm for the past few Decembers

Looking at the maps … by NOAA that measure sea surface temperature deviation from the average, one can see that temperatures have been unusually high in early December off the coast of New England for the past four years. Why would Razorbills be irrupting now if the above average sea surface temperature anomaly has been a near permanent fixture for the past four years or more?

The only unusual event that occurred this year that seems to match up nicely with the Florida invasion is Hurricane Sandy, an incredibly large and nearly unprecedented storm that hit the mid-Atlantic and New England in late October. Hurricane Sandy was an unusual beast not only for its unique landfall location and approach, but also its incredible size. As the storm was pulled northward across Cuba and the Bahamas, it began to temporarily weaken, lose convection, and suffer from dry air intrusion before it began interacting with an incoming trough. Due to the angle of the trough and the positioning of a high pressure system over Greenland, the storm began to curve northwestward and become re-energized due to baroclinic forcing — a process which also caused the windfield to expand and make Sandy the largest hurricane in diameter in the history of the Atlantic.

To put this bit of trivia into perspective, there were simultaneous tropical storm warnings for both New York City and Bermuda — a distance of about 770 miles! Her enormous windfield also resulted in a record amount of surge water being moved. The impacts of such enormous hurricanes and their accompanying surge on marine ecosystems are not well studied or understood but it may be related to the unprecedented invasion of Razorbills in Florida.

One theory is that Razorbills, which had a very good nesting season this year, irrupted in large numbers due to the fact that there was a collapse in food availability in their normal wintering range with a simultaneous bumper crop of first winter birds, causing most of the first year birds to migrate south in search of better feeding opportunities. Although birds have been seen around the entire coast of the state, there are no reports west of Pensacola yet and may never happen due to the turbidity caused by the Mississippi River. Perhaps more due to being underbirded, there have been no reports of Razorbills from Cuba or the Bahamas (both would be first national records). This irruption will likely be discussed and studied for years to come. For the time being, Florida birders are being treated to a (hopefully) once in a life time event.

Related articles

• ‘Penguin-like’ bird spotted in Fla. (clickorlando.com)
• razorbill. Victim of Hurricane Sandy (ireport.cnn.com)