Contributor
Date
Location
- Age
- Not specified
- Sex
- Not specified
- Behaviors
- Flying
Observation details
We recorded at least three dark-rumped Leach’s Storm-Petrels, with two seen at one point over a slick of fish oil over Crespi Knoll, 40 kilometers southwest of San Mateo Point (33° 06' 02.6" N, 117° 51' 26.5" W). The birds seen over the slick, in particular, were seen well over an extended period of time as they foraged in direct comparison with Black Storm-Petrels, and at one point, possibly also with an Ashy Storm-Petrel. These birds were clearly smaller than the Black Storm-Petrels, probably about two-thirds the size of the larger birds, and they flew with a more fluttering flight that to me appeared less “bounding” and to lack the accentuated, deep wingbeats of the larger birds. The overall structure of these birds was generally similar to that of the Black Storm-Petrels and maybe even more so the Ashy Storm-Petrels. All three species had short bills that were rather slim and blunt-tipped, large heads with a steep forehead and a bulbous appearance overall, plump bodies, and relatively long wings that were slim throughout their length as they tapered from bases of medium depth to pointed tips. This said, it is possible that the Leach’s Storm-Petrels had proportionately shorter wings than did the Blacks, and I thought their tails appeared shorter than those of the Ashy Storm-Petrels. My views of these birds were insufficient to have noted an obvious notch at the tip of the tail, but photos may show this. The overall plumage was sooty to blackish, but seemingly not quite as purely black as that of the Black Storm-Petrels. I further thought the carpal bars that extended diagonally across the upperwing coverts were pale gray to buff, conspicuous, and sharply demarcated. Unlike both of the other species, these birds had the rump generally sooty in coloration, but with an oval-shaped patch on either side of the rump that was light gray to whitish, and contrasting conspicuously with both the sooty color of the back that continued down the center of the rump, and the blackish color that characterized the tail. Although good views revealed a distinct contrast between the darker coloration in the center of the rump and the pale sides, the paler patches seemed diffuse in character, and when seen from a distance, the entire rump sometimes appeared paler than the back or tail. Given the lack of striking contrast between the rump and tail, I was unable to discern in the field the width of the rump relative to the length of the tail, but this is probably shown in photos. I thought the bill was black, and I failed to notice a contrast between what were presumably dark eyes and the blackish plumage of the head, but I did not ever clearly see the legs or feet even though these birds were dropping to the water over our slick, so it is quite possible that they will be apparent in photos.
Technical information
- Model
- Canon PowerShot SX70 HS
- ISO
- 160
- Flash
- Flash did not fire
- Dimensions
- 4327 pixels x 3235 pixels
- Original file size
- 1.68 MB