West winds (i.e blowing offshore) tend to move the upper layer of water east, replacing it with water brought up (upwelled) from below. This often results in increased nutrient content, which attracts baitfish. Predators follow the bait.
Manx seemed to have stolen the show since shearwaters are not commonly seen from shore, but the influx of Razorbills was impressive, as was the concentration of Humpback Whales. Based on differences in dorsal fins (humpbacks generally don’t fluke up in the shallow waters nearshore) I saw at least 5 different whales between Jennette’s Pier and the Outer Banks Pier on the afternoon of the 28th.
So clearly large amounts of forage were in play over the weekend, with impressive numbers of loons, Razorbills, Manx, Bonaparte’s Gulls, and whales feeding on the bounty.
I noticed that about the time the large number (200+) of Manx came by Nags Head going south, the wind was about to change to NE from W. I’ve seen similar situations at sea from ships where seabirds “ride” the edge of a front. Granted, this backing of the wind to NE was not frontal, but the birds may very well have been riding the edge of those brisk west winds. Once the wind shifted to NE, the spigot seemed to turn off.
From: <carolinabirds-request...> [mailto:<carolinabirds-request...>] On Behalf Of Ricky Davis
Sent: Wednesday, February 01, 2017 2:10 PM
Subject: Manx Shearwater flight off Nags Head
Some may not have heard about this, but this past weekend - especially on Sunday, there was a massive movement of Manx Shearwaters, seen from shore!. During a 3 hour period (9am to Noon), a count of 217 birds was made. Practically all the birds were moving in a southerly direction, observed at distances as far as could be seen with a scope to as close as several hundred yards! Some were observed to stop and join feeding groups of Razorbills, gulls, and loons, but usually resumed their flight in a few minutes. Small numbers were observed in the days preceding and following the Sunday flight also.
Needless to say, after searching for previous Atlantic Coast from-shore sightings, this was unprecedented. If anyone knows of anything remotely like this from States farther north of NC (VA, NJ, MA) please let us know. Also we would like to know if there was any unusual weather, currents, food sources, that might have been a causative agent for this movement so close to shore.