Readers’ wildlife photos

Well, this is the last batch of photos I have, so you know what to do.

Today’s contribution is from Ephraim Heller, this time with photos from America rather than Brazil. Ephraim’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

It has been a busy January on the Snake River in Grand Teton National Park.

After a warm early winter, a few weeks ago we finally had a hard freeze. A branch of the Snake River froze solid. However, there is a location where a warm spring feeds into the branch and this inlet stayed open. Hundreds of Utah sucker fish (Catostomus ardens) were trapped in this area of open water surrounded by ice, isolated from the main body of the Snake River. Naturally, this provided a smorgasbord for the local bald eagles and coyotes.

As I observed the Utah suckers at various times of day, I noticed that in the late afternoon they would all rise to the surface and expose their dorsal fins. Intrigued, I queried my AI which informed me that this is a matter of oxygen dynamics:

• The warm water holds less oxygen than cold water, and thermal springs typically have low dissolved oxygen content due to high temperatures.
• In confined areas with high fish density, oxygen is rapidly depleted.
• Fish respond to low oxygen levels by “piping” or “aquatic surface respiration” (ASR) when oxygen levels drop below critical thresholds. This behavior involves positioning at the water surface with mouths/dorsal fins exposed to access the oxygen-rich surface layer. This behavior indicates that the fish are stressed.

However, the AI also stated that “Aquatic plants produce oxygen through photosynthesis during daylight, with peak production in late afternoon. At night, plants consume oxygen through respiration. Dissolved oxygen levels are highest in late afternoon and lowest just before dawn.” This doesn’t seem consistent with the timing I observed.

I don’t know how much of this is true vs. AI hallucination, but it sounds plausible to me. I’d appreciate it if the ichthyologists and limnologists among the readers would confirm or refute this story.

Now for the photos:

Here are the Utah sucker fish at the surface of the open water pool in the evening, trapped by the surrounding ice:

Here is a close up of the fish at the surface:

Every so often the fish would go into a frenzy at the surface. I don’t know why. It was unrelated to anything I saw happening at the surface. Here is a bald eagle (Haliaeetus leucocephalus) watching the frenzy and assessing his menu options:

Having made up his mind, the eagle helps himself to a serving of fresh fish:

The common ravens (Corvus corax) have found a lovely rotting fish. Instead of exerting the effort to catch a fresh fish, this eagle has decided that it is easier to steal the carrion:

Bald eagles are kleptoparasites, so when an eagle with energy and initiative catches a fish the other eagles won’t let him dine in peace:

Ravens are smart birds. This one is surely thinking “If those eagle ignoramuses can catch a fish then surely I can do it better.” Unfortunately for him, the fish got away:

In spite of their inability to fish, common ravens are handsome birds:

To my surprise, the North American river otters (Lontra canadensis) who live half a mile downstream have not been dining at the buffet. I think it is because this branch of the river is frozen solid and the otters don’t like traveling on the ice surface for long distances without the safety of accessible water. So I donned my cross country skis and visited them at another, unfrozen branch of the Snake River. They, too, were feasting on Utah suckers:

Also on the river are trumpeter swans (Cygnus buccinator) in the morning mist:

Trumpeters need a long runway to take off. These four are just starting to accelerate:

Once airborne they are graceful:

Finally, this old-time general store sits adjacent to the Snake River in Grand Teton National Park. In this star trail time lapse, the stars are, of course, circling Polaris, the north star. The Tetons are to the left of the store: