Thursday, August 28, 2014

Colorful Blackbirds

Blackbirds appear in kids' earliest drawings, marching around the terrain like they own the place. They get our attention by being noisy, argumentative, kibitzing, often flocking in great numbers. Their behavior is colorful. We kids could represent it with a single bold crayon - black.
We knew about crows, the big blackbirds. They showed up in folklore with elements of wisdom and mischief. We had the feeling that crows were talking about us up there in the treetops. They were smart enough to tell each other apart even though they all looked alike.

The smaller blackbirds looked like gangsters that would take over whole fields or telephone wires. If you saw grackles in the right light they sported magical colors. But you couldn't reasonably say that a blackbird was blue. There wasn't a solution for that in the crayon box.

I looked up iridescence on Wikipedia. It said that peacock feathers are actually brown, made vivid by various internal surfaces microscopically structured to interfere with visible light, sometimes in combination with pigments. Out of that comes decorative hues with glossy, metallic sheens.
Over at Halibut Point I took a closer look at cowbirds to see if there might be more to them than basic black. Bronzy mantles distinguished the heads of the males.

Blackbirds with flashier accessories come foraging to Halibut Point from the cattail swamp across Granite Street. Red-wings were probably the next step we took with crayons, adding a vivid splash at the shoulders.
It turns out that ornithologists classify grackles, cowbirds and red-wings together within the icterid family, next to crows. Icteridae refers to yellow feathers in Greek. The family includes orioles.
Female Baltimore oriole
Orioles don't look particularly black. Gloucester's Chris Leahy offers a calming overview of these relationships in his essay on "Systematics" in The Birdwatcher's Companion. Members of the blackbird family diverged relatively recently from common ancestors. 'Adaptive radiation' continues all around - and within - us.
Then we have a black bird that is not a blackbird. Taxonomically, the starling resides in the sturnidae family alongside but not within the icteridae. Its compact sturdy body suggests a different lineage. In the right light its colorful iridescence helps to compensate for its swarming vulgarity.
Back on apparently firm black ground the crow anchors the corvid family, the third branch of blackbirds. Like the others corvidae are considered songbirds even if their caws and other chatter don't appeal to us musically. Crows are smart and social. The fellow pictured above interrupted his preening routine about every twenty seconds to send a message to compatriots in the neighborhood.
Crows have meaningful complexities in their coloration that help distinguish the sexes and individuals. The patterns that are invisible to us include their ability to see ultraviolet and iridescent subtleties that organize crow life. They know who's who in crowdom.
Blue jay
The corvid family has transcended black by engendering magpies and jays, who fully retain the family's rascally nature and its near-human brain-to-body weight ratio. Like most colorful creatures blue jays enjoy their own splendor and provide a loquacious account of their doings.
I walked about Halibut Point pondering the mélange of coloration and classification that assigns black and blue to the same family. When a flock of jays screeched overhead in tenor variations of a crow's honest 'caw-caw-caw,' I understood the pairing straight from the corvid's mouth.

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