I have watched a number of feasting animals — birds, bears, coyotes, deer, wasps, spiders — and at no time have the words, picky eater, sprung to mind. That is, with one exception: a dipper.
An uncommon bird of western North America, the American Dipper can sometimes be found hunting in clear, fast-moving mountain streams. Fortunately, I live near a creek where there is often a concentration of dippers (eight seen last Saturday), so I get to watch its behaviour. This easy access to the bird has enabled me to write an article for the BC Field Ornithologists about the way dippers handle surface and anchor ice in cold weather: dippers and ice. I have even watched it tending its chicks.
The dipper is an unusual songbird. It flies underwater to capture aquatic larva and fish eggs from the creek bed. Occasionally it will even capture fry swimming within the stream. About a year ago, I was watching a dipper collect kokanee eggs from the creek bed and was struck by the fact that it would retrieve a group of them, but would then place them on a surface so it could eat them one at a time.
This time, I was struck by the dipper’s behaviour where it would retrieve a clutch of kokanee eggs, but not swallow them upon bringing them to the surface. Rather, it would pause and examine them.
As before, it would first place them on a surface.
It then tried to pick them up one at a time, but unfortunately they were clumped together. So it tried to separate the eggs by twisting and shaking its head. Why it had to eat them individually rather than all at once is unclear. But, having failed to separate them, it then put them down on the rock again.
Oh well, it is time to start all over again. It stuck its head back in the water and this time seems to have grabbed a grub. Food must be plentiful for it to afford to be so picky.
I also enjoy watching water ouzels (dippers) but I haven’t studied them so closely. It seems odd that an animal would expend energy gathering food and then not eat it. Maybe the dipper saw some embedded grit? That it was willing to reject the mass of eggs and look for more is a sign of plentiful food and a healthy stream ecosystem. Squirrels gather and store large amounts of food, burying it or hanging it in trees, and then not use it, perhaps because it was surplus or it’s location was forgotten. As always, wonderful images and observations Alistair.