As it’s Sunday, we have a themed batch of bird photos from John Avise. Today’s theme, like last week’s, is about bird eyes. John’s notes and IDs are indented, and you can enlarge the photos by clicking on them.
Don’t miss the leg-banded female woody at the end!
Eye adornments must be important in avian behavioral signaling and non-verbal communication. I say this because the eyes of many bird species have evolved colorful irises (see last Sunday’s WEIT post) or are otherwise exaggerated in appearance, much as people’s eyes vary with iris color or eyelid mascara.
Another way that avian eyes may draw attention is via the presence of eye-surrounding circles known as “eye-rings” that give the birds a spectacled look (much like large-rimmed eye-glasses on people). This week’s post shows several examples of North American avian species with notable eye-rings, which are a useful aide in species’ identification by birdwatchers. Because eye-rings have evolved independently many times in different avian taxa, we can speculate that they probably serve some adaptive role, perhaps in inter-bird communication or species recognition. But precisely what that adaptive role is remains uncertain. Readers are welcome to suggest potential roles for eye-rings, or how any such hypotheses potentially might be tested.
American Robin (Turdus migratorius):
Blue-gray Gnatcatcher (Polioptila caerulea):
Blue-headed Vireo (Vireo solitarius):
Hermit Thrush (Catharus guttatus):
Ovenbird (Seiurus aurocapilla):
Pacific-Slope Flycatcher (Empidonax difficilis):
Ruby-crowned Kinglet (Corthylio calendula):
Rufous-crowned Sparrow (Aimophila ruficeps):
Yellow-throated Vireo (Vireo flavifrons):
Townsend’s Solitaire (Myadestes townsendi):
Solitary Sandpiper (Tringa solitaria):
Laughing Gull (Leucophaeus atricilla):
Ring-necked Duck hen (Aythya collaris):
Wood Duck hen (Aix sponsa):