Offshore Seabirds and Weird Whales

Aug 21, 2019

Credit Peter Swaine / flickr / bit.ly/2Zneqko

As you might expect, I religiously check the eBird rare bird alerts for the three Cape and Islands counties – Barnstable, Nantucket, and Dukes. This week, the Nantucket alert was blowing up with rare seabirds from faraway lands. 

Tropicbirds from the southern Caribbean, Black-capped Petrels and Band-rumped Storm-petrels from warm southern Gulf Stream waters, and a South Polar Skua from, well, the South Pole. What’s going on? Did some hurricane slip in, literally under the radar, and blow these birds north? Did the Gulf Stream take a sharp left all of a sudden? The answer, it turns out, lies more in the eccentricities of offshore geographic boundaries, and some research into some amazing and obscure whales, than with any sort of rare bird event.

A visiting birder might see these reports and start booking their ferry tickets to Nantucket – these species represent a who’s who of rare seabirds high on many birders wish lists. But hold on there, fella. A quick click of the map feature associated with these eBird reports shows that most of these birds were actually seen from a boat off the continental shelf 150 miles southeast of Nantucket, and no amount of squinting from Sciasconset will get them on your list. Since Nantucket is the closest point of land, these sightings end up in the Nantucket County rare bird alert. But unless you are aboard the research vessel Hugh Sharp you have essentially no chance of seeing these birds. Or do you? More on that later.

This ship, the Sharp, has been hugging the shelf in search of some of our most mysterious and impressive cetaceans, the beaked whales. Very few species of beaked whales are well known, some only from occasional beached specimens. They include the deepest diving mammal on earth, the Cuvier’s beaked whale, which can dive to a depth of two miles or more, holding its breath for two hours. Because they dive so long and so frequently, are so rare, are relatively solitary, and hang out so far from land, they truly are international whales of mystery. I’ve only seen a few quick spouts of unidentified individuals on birding trips well offshore. This research is actually based out of the prolific Northeast Fisheries Science Center right in Woods Hole, and has provided the first detailed information about the True’s Beaked Whale, including dozens of sightings and acoustic recordings of a species only documented 12 times since they were first described in 1913.

And whether by luck or by design, aboard this whale-chasing cruise is a birder who has been recording and posting his observations, including an impressive 6 Black-capped Petrels, 21 Band-rumped Storm-Petrels, and 8 Audubon’s Shearwaters, as well as the single Red-billed Tropicbird. All of these are drool-inducing species for a birder. “Bird Guy”, you say, “I’m not a beaked whale researcher. How can I see these birds?”

Well, you may be in luck. The Brookline Bird Club has cornered the market on what they call “extreme pelagic trips”, running several a year from Hyannis to the deep, warm waters of the continental shelf and associated canyons. Whether you want a chance at seeing True’s Beaked Whale, a Whale Shark, some bottlenose dolphins, or any number of seldom seen seabirds, these trips are for you. The August 24th trip is already full, but another is scheduled for late September. These overnight trips to potentially rough waters well over 100 miles from shore are not for the landlubber. As a former leader of these trips who has been “green about the gills” more than I care to talk about, let me just suggest that packing some Dramamine and saltines might be prudent, just in case you get “chummy” with the rail.