It’s Sunday Seabirds! Today’s photos are from reader Bruce Lyon, whose notes are indented. (And readers: keep those photos coming in.)
A couple of weeks ago I sent you some photos of cormorants, birds that swim under water using their feet for propulsion. Here are some photos of Pigeon Guillemots (Cepphus columba), diving birds that use their wings for propulsion under water. Guillemots are common along the coast in and around Santa Cruz, California and they nest right in town along Westcliff Drive.
The photos below were taken near Davenport, a few miles north of Santa Cruz. I took these photos as a test of new full frame sensor camera body I purchased (Canon 6D). I decided to try a full-frame sensor body because they seem to yield better images (less noise or grain) at low light situations that demand high sensitivity (high ISO settings). The first four images were shot at 2000 ISO. For comparison, when I used to shoot film I used Kodachrome 64 (e.g. ISO 64)—the new technology enables images that would have been simply impossible with film!
Each spring before nesting season, the guillemots start to hang out in little groups on shelfs below their nesting cliffs. There is lots of chasing, courting and copulation in these groups. The sexes are similar and both have lovely bright red feet and mouth linings. Despite many hours spent watching these birds, I have still not figured out whether the foot and mouth colors are used in mate choice, competition for resources (nest cavities), or both. Guillemots nests in small holes and crevices in the cliff faces and there seems to be a lot of competition for high-quality nest sets. Perhaps pairs of birds with particularly colorful feet are superior competitors.
Below: A bird chased off the rock shelf got tangled in an algal strand in the process of fleeing.
More red booties:
A chase. Note how the mouth lining matches the feet.
Below: a closeup of the mouth lining:
A small group interacts over possession of a nest cavity. The bird in the lower left of the photo is at the entrance of the nest cavity:
Before copulating, guillemots do a little dance where they walk around in a tight little circle several times:
A copulating pair:
Since guillemots spend most of their time on the water, it only seems fair to show one photo of a swimming bird:
Guillemots, like the rest of their auk relatives, face a trade-off. They use their wings to fly through the air, but they also use them to “fly” under the water. It seems that optimal wing size for flight through air differs from the optimal wing size for swimming because the auks all have small wings for their body sizes compared to other birds. This matters because birds fly by countering gravity with lift, and all else equal, lift is proportional to wing area. In technical terms, auks have extreme ‘wing-loading’— they have to lift a high mass per unit area of wing. They can compensate for this by flying fast, since lift increases exponentially with flight speed.
Thanks for the wonderful photos, Bruce!
That reminded me of a recent result doing the rounds:
“SHAPE OF BIRD WINGS DEPENDS ON ANCESTORS MORE THAN FLIGHT STYLE
In a finding that could change the way scientists think about bird evolution, researchers have found that the shape of bird wings is influenced more by how closely related species are to one another than by flight style.
The research challenges scientific beliefs that assume the way a bird species flies—whether it primarily dives, glides or flaps, for instance—plays the primary role in the evolution of its wing shape. It also indicates that it may be more difficult than previously thought to infer flying behaviors of early birds and the first flying dinosaurs from fossils alone. …
The study is the first to analyze wing geometry across all major groups of birds. Researchers analyzed over 100 photographs of wings from different bird species.”
[ https://www.jsg.utexas.edu/news/2015/11/shape-of-bird-wings-depends-on-ancestors-more-than-flight-style/ ]
If it stands up [is images enough? but they also looked at details of real wings], it could possibly fly the optimizing hypothesis – lots of leeway in wing shapes – or sink it.
Also, the link has a nice cladogram, so it fits with the nice bird photos!
Then again, alcids were for quite a long time given their own sub-order, assumed to be only distantly related within Charadriiformes to other suborders Lari and Charadrii. When it turned out that they were deeply nested within Lari, and in fact most closely related to skuas, that came as a big surprise and was resisted for a while. So something must be changing with lifestyle rather than relationships.
A really beautiful bird. The red booties and mouth lining seem to be accentuated by their stark contrast with the black plumage. I think they dress to make a big impression.
Ah, Bruce, I so enjoyed this set of pictures! Not only are they beautifully done but you’ve captured so many aspects of this species’ lifestyle and behavior–there’s just so much here to contemplate! Doesn’t hurt, either, that guillemots are right near the top of the cute scale. 🙂 That shot of the bird with feet tangled in algae is just an incredible capture!
Easy to see why auks are sometimes called the penguins of the northern hemisphere.
Outstanding pictures – wing load and all.
Beautiful photos! This Pacific species, looks quite similar to the North atlantic one I’m more familiar with (Cpphus grylle). Except that it is prettier on pictures because one sees their eyes, which look spectacled – the Atlantic species has such a dark face that the eyes are almost invisible most of the time.
As for the size of the wings, I cannot refrain to compare to the gannets, who also swimm underwater with their (half folded) long wings. See here.
Your link isn’t working for me.
I love the red feet! The first picture seems to say: “Make way for my lovely feet!”
Yes – LOVE the red feet!
Marvelous. I do not know a guillemot from a cormorant, but since the bright markings are seen in both males and females it could be that this is a case of mutual sexual selection. That is, the colors stimulate them to accept each other as a mate. Sexual display colors in both sexes are common in birds where both parents take on the task of rearing the chicks. I suppose the same colors can be part of their ‘Hey! get off my lawn’ displays to their neighbors.
Thanks Bruce (and Jerry). I really enjoyed that.
I believe lift increases as the square of flight speed, not exponentially.
https://www.grc.nasa.gov/www/k-12/WindTunnel/Activities/lift_formula.html