Black-capped Petrels were certainly the stars of the weekend! These petrels seem to despise a jaeger or skua and will chase them when they are in the vicinity. We had a lot of interactions on Friday with as many as six Black-cappeds chasing a Pom at once. They would gather up behind the Pom and then close in, swooping closely ahead again and again (photos Peter Flood & Kate Sutherland).
Both morphs of Black-capped Petrel were found on these trips though most of the individuals we encountered were intermediate between the two. Light form, or light morph, birds tend to be larger than the dark birds and have less black in their plumage. As you can see in the photo below this bird has a small, black cap with some white showing above the eye, a narrow dark bar on the underwing, and white median and greater secondary coverts.
The dark form, or morph, is darker (of course) and smaller than the light morph. They have a dark face as opposed to just a cap and this runs into a smudgy nape. The underwings have a thick dark bar and they can have varying degrees of black on their median and greater secondary coverts. The chest spur is usually a broad smudge.
Thank you to everyone who joined us out there, and those who made the trip for the day we weathered out! A big thank you also to our leaders Peter Flood, Ed Corey, and Liam Waters for helping us on both trips, they also contributed photos for this post.
Species List May 7 / 9
Fea's Petrel - 0 / 1
Black-capped Petrel - 70 to 80 / 35 to 45
Cory's Shearwater - 3 / 2
Cory's type shearwater - 1 / 0
Sooty Shearwater - 3 / 2
Audubon's Shearwater - 5 / 7
Wilson's Storm-Petrel - 200 to 220 / 45 to 55
Red-necked Phalarope - 5 / 44 to 45
Red Phalarope - 0 / 5
Pomarine Jaeger - 2 / 1
Parasitic Jaeger - 1 / 0
Laughing Gull - 1 / 0
Least Tern - 3 / 0
Common Tern - 7 / 16
Chimney Swift - 0 / 1
Black-bellied Plover - 0 / 1
Red Knot - 1 / 0
Dowitcher - 0 / 23 to 24
Chestnut-sided Warbler - 0 / 1
Beaked whale species (likely Mesoplodon species) - 0 / 1
Bottlenose Dolphin (offshore population) - 3 / 7+
Portuguese Man of War - 0 / 4
Another photo of the Fea's Petrel by Ed Corey
A few more Black-capped Petrel images!
Flying with Wilson's Storm-Petrels in the slick (Kate Sutherland)
The Wilson's were so obliging feeding on the chum on Friday's trip! (Kate Sutherland)
Dark morph Parasitic Jaeger (Kate Sutherland)
Common Terns were very attentive in the slick (Ed Corey)
And one even looked to have a filefish! (Kate Sutherland)