Nature Where I Live: San Francisco: Nectar Robbery

Anna's Hummingbird, Nectar Robber

Every now and then I'll notice hummingbirds going for flower nectar by probing between a flower's corolla and calyx rather than going straight down the flower tube. I looked up the phenomenon and was surprised to see it called "nectar robbery." The term "illegitimate" also gets used to describe this behavior, because the bird gets its reward without contacting the anthers or stigmas to pollinate the flower.

But is it still "robbery" if native hummingbirds are doing this to non-native horticultural plantings? Of course not. The natives are simply adapting to the human disturbance of their landscape. Botanists ought to come up with non-pejorative terms for the intelligent behavior of hummingbirds who take advantage of available non-native plant resources.

Anyway, it was great to get out again today after being hunkered down with a cold the last few days. Unfortunately, I had just recently finished watching all eight seasons of Homeland for the second time before I got laid up, but I did enjoy perusing The Best American Science and Nature Writing 2025.

I was interested to see an Allen's hummingbird nectaring on the tiny flowers of white ramping fumitory (Fumaria capreolata). The flowers are cleistogamous, or self-pollinating, so there's no chance of any nectar-robbery shenanigans by the hummingbird. However, its nectar ordinarily attracts bees and flies.

Resting After Visiting Fumitory Nectar Spurs

Instead of going back to the fumitory, the hummingbird flew to a nearby poison hemlock, where it appeared to be more interested in whatever the leaves were offering instead of its umbels of little white flowers.

At Mallard Lake, the usual suspects were taking advantage of the little creek.

Brown Creeper

Fantail

Red-winged Blackbird at Elk Glen Lake

The Wilson's warblers are still singing as they forage through the treetops. This one obliged me by briefly pausing in the open.

Allen's Hummingbird Near The Salvia Patch

The treatment is actually for a pretty yellow-flowered plant called capeweed (Arctotheca prostrata), so it's more of an herbicide treatment.

This devil's coach-horse beetle (Ocypus olens) had just avoided being eaten by a robin that hopped over from the grass to give it a go. The beetle raised its abdomen and presumably fired off its stink glands since the bird dropped it from its beak almost instantly.

The robin went back to foraging in the grass where it appeared to keep an eye out for predators flying above. After all, a robin doesn't have a stink gland to fall back on....

The paper wasp nest is still coming along.

Several blue-eyed darners were buzzing about near the cattails at Metson Lake (where I saw a female hummingbird collecting cattail fluff; apparently nesting season is still on, a second clutch in the making).