28 July 2013
Aboard the Henry Bigelow, Days 2-5 mammal & bird sightings
Our survey is short, but we’ve packed in as much as we could in our few days on the vessel. The visual observer teams were on-effort pretty much all the time between sun up and sun down each day. We started scanning for animals pretty much as soon as we left Newport, and collected data on cetaceans seen during transit until sunset. Balaenopterids, particularly fin whales, made up the majority of sightings on that route. Common dolphins were also nearby, yet few chose to approach and give us a better look. The common dolphins pictured were the exception. Throw in some basking and thresher sharks and all in all it was a beautiful day to finally be at sea.
Our diversity of species was the highest on the 26th, including sperm whales and pilot whales, Risso’s, bottlenose, spotted and striped dolphins. Oh, and we got our beaked whales! Cuvier’s and Sowerby’s were documented, along with distant Ziphiids that could not be identified to species. As the day progressed we spotted more Sowerby’s and attempted focal follows.
Unfortunately, on Sunday our quest for Mesoplodonts was hampered as weather conditions deteriorated through the day. We had numerous sightings of Cuvier’s but no confirmed species identification for other Ziphiids. Sperm whales, Risso’s dolphins and smaller Delphinids were encountered and again, most were camera shy.
Waking up on Monday, it was apparent that seeing any animals at all would be problematic. We reduced visual effort considerably due to high wind and seas, spray, and rain showers. From inside the bridge we searched for any animals that just might stand out against the waves and foam. Sadly, what we mostly saw were waves and foam, and gloomy skies. The seas continued to build throughout the day, so we had to abandon the trackline we were surveying and work our way to the northeast, down-swell. Monday night was really bumpy – nothing like 30kt winds to toss one around a bit, but the ride home for the end of the cruise looks more promising.
The bird team jumped right in where we left off this spring and hardly missed a beat. Or, actually, that should be not missing a bird (we don’t miss birds out here, you know). But my oh my, what a difference a couple of months can make. With just three days so far on this survey, we’ve already tallied 395 birds of 17 species. You read that right: seventeen! Taking the top three spots in terms of overall abundance and detection frequency were the expected summer visitors to the northwest Atlantic: Wilson’s Storm-Petrel (183), Cory’s Shearwater (81), and Audubon’s Shearwater (27). These are the bread-and-butter of the summer seabird survey sandwich around here. But we want our cake and eat it too—the crème de la crème for those with exotic tastes—the dapper White-faced Storm-Petrel. We certainly weren’t expecting to find nine in only three days! These gorgeous and unmistakeable storm-petrels with their swinging pogo-stick flight, effortlessly bouncing across the ocean, are considered to be rare summer visitors here from the east Atlantic. And here they are, being found almost daily over deep warm water seaward of the shelf break, beyond the reach of most day trips. Only on these surveys can we get a better understanding of their true distribution and abundance.
Taking top spot this week was, not surprisingly, a seabird in the genus Pterodroma. Seabirds in this genus tend to draw a lot of attention to themselves by virtue of being hard to find thanks to their propensity to remain far from land—very far—often not approaching any closer to the continent than the shelf break. Hence, seeing one tends to generate a fair amount of excitement. The Trindade Petrel seen on Saturday was the first live one seen in New England waters (one washed up dead on a Maine beach this spring). The occurrence was documented with identifiable photographs (these birds don’t linger for very long) thanks to Jessica Aschetinno’s snappy trigger finger. This species nests on several small islands off Brazil and wanders north, entering the Gulf Stream, where most are found on spring and early summer commercial birding trips off North Carolina.