This driftline scene is on the unusual side, not super unusual, but unusual enough to get you thinking. If it’s not clear what’s going on, a double-crested cormorant nabbed a barred surfperch a tad too large. It illustrates that minor mistakes in the everyday choices faced by predators can turn fatal. The thing about surfperch is their backward-pointing dorsal fin spines. A surfperch of a certain size, once headed down a cormorant gullet, will not be backed out.
Discovered by Carol Comeau on the beach near Cayucos, California, on November 4, 2019, this double fatality isn’t my first brush with cormorants killed by stuck surfperch. Three years ago, I reported another deadly lapse in judgement, if judgment is an applicable cormorant term. In Brandt’s Cormorant Doesn’t Survive Attempt to Swallow Barred Surfperch I included a remarkably similar image of a Brandt’s cormorant and a barred surfperch, and I related an equally unfortunate encounter between a Brant’s and a plainfin midshipman. Midshipman are notable for flaring their spiny gill covers in defense.
It makes sense that spiny prey are tricky for fishing birds that swallow their prey whole. Bigger prey are desirable for their higher energy content, but they can be deadly in the gullet. I don’t claim to know the cormorant mind, but it looks like, to use a human analogy, some of them are risk takers. Inevitably, some of those end up on the wrong side of the fuel-risk tradeoff. That’s the trouble with surfperch of a certain size. It would be interesting to know the real mishap rate and whether risk taking is more likely in hungry birds.
I thank David Leal for confirming identity of the cormorant. For help with the surfperch, I called upon Michael Westphal, Gary Longo, Kristine Lesyna, and Ken Oda. I ask them for a lot of fish ID assistance and I thank them a ton for their patient support. Most of all, I thank Carol Comeau for sharing the details of her observation and her great photo. I’m also grateful to Nancy Mann for alerting me to Carol’s discovery in the first place.