storm-petrel sp. (white-rumped) - Tom Benson

ML107495331

storm-petrel sp. (white-rumped) Oceanitidae/Hydrobatidae sp. (white-rumped)

Report

Contributor

Date

Location

Lausen Sea Mount
Orange, California, United States
Media from this location Illustrated Checklist
Map
Map Coordinates: 33.3974106, -118.0006099
Age
Not specified
Sex
Not specified

Observation details

TAB notes: As we were circling the sea mount, JLD spotted a storm-petrel among the fishing boats over the high spot, so we motored closer to try and find it. As we got to that location, someone re-found it, and we were able to view it at a distance of about 100 meters for a minute or so as it was flying near a small fishing boat. I picked it up again at a somewhat greater distance, but lost track of it shortly after. During these two periods of observation I noted that this storm-petrel appeared smaller (or at least shorter winged) than a Black Storm-Petrel, with a "flappier" flight in which the wings were constantly flapping without any of the gliding or deeper, slower wingbeats exhibited by Black Storm-Petrels. My recollection is that the flight was more direct, with occasional pauses to hover, and not the more leisurely cruising of a Black Storm-Petrel. It was after this second period of observation that JMB noticed that his photos showed a pale rump. We searched for this bird for quite some time, but to no avail. My poor photos, as well as JMB's, show what appears to be a relatively small, dark storm-petrel with a pale (but not gleaming white) rump that did not extend down to the sides of the rump, a distinctly pale carpal bar, and a short tail. In the field no one who observed the bird noticed a white or pale rump; I believe a gleaming white rump would have been visible on this bird given our views, suggesting that this bird had a dingy whitish rump typical of a Leach's (including Ainley's and Chapman's) or Townsend's Storrm-Petrel, and not the white rump of a Wilson's or Wedge-rumped Storm-Petrel. My own experience with these species is rather limited, so I am content to leave this bird as an interesting storm-petrel that got away.

Technical information

Model
Canon EOS 7D Mark II
Lens
EF100-400mm f/4.5-5.6L IS II USM
ISO
1000
Focal length
400 mm
Flash
Flash did not fire, auto
f-stop
f/5.6
Shutter speed
1/8000 sec
Dimensions
541 pixels x 431 pixels
Original file size
156.55 KB