Point Loma, California: American Oystercatcher or American x Black Oystercatcher Hybrid? (1 Viewer)

[John T in AZ]

I took these photos September 1st, 2023 at the Point Loma Tide Pools in San Diego (eBirds refers to it as Cabrillo NM--tidepools).

The Oystercatcher in question was with the Black Oystercatcher the entire time we observed it. Different species do congregate together of course.
At first I thought it was an American Oystercatcher. Thinking back, I spoke to some birders on the trail who were looking for a hybrid that they heard/read about. Perhaps this was it.
After reviewing eBirds for September and the four previous months I see that there were no sightings for American Oystercatchers. However, four of those months reported sightings of a hybrid.

Could this be an American x Black Oystercatcher Hybrid?

John T

 

[Butty]

Can't see any reason from these photos to think it's other than a (non-hybrid) adult American oystercatcher.

 

[rkj]

Birds more-or-less like this appear in southern California from time-to-time. The can stay for an extended period and engender a good deal of debate among the local birders. Being in northern California myself, I try not to pay too much attention to the discussions, and I do not know what is the thinking on this particular bird. My own thought though is that the ragged border between the white and black on the breast, the mixture of black with white up toward the shoulder, and the traces of white on the wings all suggest this is a hybrid.

 

[njlarsen]

I uploaded an image of a bird from Colombia today to the gallery. It is less extreme than the bird in this thread, but still seems to show some of the same signs. Neither Black Oystercatcher or Blackish Oystercatcher from South America breeds anywhere near where this was photographed. Link to my photo:

American Oystercatcher P1270907.jpg

www.birdforum.net

Niels

 

[Joern Lehmhus]

I would agree that it seems most likely a hybrid. This may be interesting in that respect:

American Oystercatcher v. hybrid discussion in CA

https://ebird.org/species/x00006?siteLanguage=hr

 

[John T in AZ]

Thank you all for your replies. I'm out of town so pretty much out of touch.

Great articles Joern. I'll have a read.

I will submit my photos on eBird to see what the "pro" consensus is.

On a side note, I captured a life bird yesterday (while broken down in an Alabama rest stop) - a Brown-headed Nuthatch. Fun times!

 

[Michael Long]

Hybrid imo, note the speckled transition between the black and white in the breast, for "pure" american oystercatcher, that transition would be sharp, clean, and without any speckles.

 

[Butty]

for "pure" american oystercatcher, that transition would be sharp, clean, and without any speckles

Apparently not so. East-coast birds (which are presumably safe from hybridization with any other oystercatcher species) seem (from Macaulay pics) quite commonly to have an un-sharp chest-division:

ML609928653 - American Oystercatcher - Macaulay Library

Macaulay Library ML609928653; © Vidhya Sundar; Cape May, New Jersey, United States

macaulaylibrary.org

ML610104897 - American Oystercatcher - Macaulay Library

Macaulay Library ML610104897; © Valerie Burdette; Barnstable, Massachusetts, United States

macaulaylibrary.org

ML610105092 - American Oystercatcher - Macaulay Library

Macaulay Library ML610105092; © Valerie Burdette; Barnstable, Massachusetts, United States

macaulaylibrary.org

ML610105097 - American Oystercatcher - Macaulay Library

Macaulay Library ML610105097; © Valerie Burdette; Barnstable, Massachusetts, United States

macaulaylibrary.org

I haven't found one to match the OP's, but the difference isn't so great that it would be difficult to imagine one occurring.
In view of this, it seems much more likely that the OP's bird is a normal American oystercatcher with an unusually un-sharp division than that it's a hybrid - especially as the main upperparts colour and rear-underparts colour show no black-oystercatcher influence at all.

the mixture of black with white up toward the shoulder, and the traces of white on the wings all suggest this is a hybrid

'Fraid I can't see why (extra?) traces of white should indicate hybridization with an all-black species. These features seem fine for (normal) American oystercatcher, perhaps with feathers slightly disarranged.

 

[rkj]

'Fraid I can't see why (extra?) traces of white should indicate hybridization with an all-black species. These features seem fine for (normal) American oystercatcher, perhaps with feathers slightly disarranged.

True enough with regard to the wings. My point about the shoulder area is that there was black speckling with the white, which I do not think is usual for a pure American Oystercatcher.

Looking at ebird reports for Pt. Loma and nearby sites, there are many reports of an American x Black Oystercatcher hybrid, and none of a pure American Oystercatcher, at Pt. Loma this year. There is one, a juvenile, clearly a different bird, that some think may be a pure American, about 20 km away. The last pure American recorded at Pt. Loma was in 2019, but details of the plumage of that bird show it was a different individual from this year's bird. Photos on ebird of the bird at Pt. Loma this year seem to show the same individual as discussed in this thread. Clearly the local birders, who have dealt with the issue of distinguishing pure from hybrid oystercatchers with several birds over many years, think the bird at Pt. Loma this year is a hybrid. I am inclined to respect their opinion. I will acknowledge that their opinion may be based in part on photos showing traits of the bird that we cannot see in these photos.

 

[Butty]

there are many reports of an American x Black Oystercatcher hybrid, and none of a pure American Oystercatcher, at Pt. Loma this year

Maybe they're wrong. Maybe this is a different bird. 🤷🏻

 

[rkj]

Maybe they're wrong. Maybe this is a different bird. 🤷🏻

They are experts on this problem. It looks like the same bird.

 

[Butty]

I'm convinced.