Blue Feathers
The colors in the feathers of a bird are formed in two different ways, from either pigments or from light refraction caused by the structure of the feather. Red and yellow feathers get their color from actual pigments (carotenoids) that come from the bird’s diet. Blue, however, is a structural color, created by the way light waves interact with the feathers and their arrangement of protein molecules, called keratin.
Thus, no birds have blue feathers made from pigments – they are blue strictly from the structure of the feathers. Different keratin structures reflect light in subtly different ways to produce different shades of what our eyes perceive as the color blue.
If you observe the blue feather of an Eastern Bluebird, Blue Jay or Indigo Bunting in normal lighting conditions you will see the expected blue color. However, if the feather is back-lit, and the light is transmitted through the feather, it will look brown. The blues are lost because the light is no longer being reflected back and the brown shows up because of the melanin in the feathers.
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Male Indigo Buntings Singing
As with many species of birds, only male Indigo Buntings sing. Their distinctive paired notes are often broadcast from the top of a tree during the breeding season. This song serves as a “keep out” signal to other male buntings, as well as a means of attracting a female. (To hear the Indigo Bunting’s song, go to https://www.allaboutbirds.org/guide/Indigo_Bunting/sounds.)
While some birds hatch knowing the songs they will sing as adults, most songbirds begin learning their songs while still in the nest. They listen to adults, either their fathers or neighboring males, singing around them. According to Cornell Laboratory of Ornithology, about 80% of first-year males in their first spring season copy the song of an older neighboring territorial male. Following fledging, young birds attempt to replicate these songs, practicing until they have matched their tutor’s song.
During the breeding season, Indigo Bunting song rates vary with stage of nesting. The greatest frequency occurs in unmated males (680 songs per hour). During nest-building, the frequency drops to 24 songs per hour, but increases once the female has completed laying eggs.
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Elm Seeds Important Early Source of Food For Wildlife
Tips of American Elm (Ulmus Americana) branches dropping on the ground alerted me to the fact that something was going on in the crown of the elm tree above me. Sure enough, a Gray Squirrel was busy dropping branch tips after harvesting the elm seeds on them. Because their seeds develop long before most seeds are available, elm seeds are sought after by numerous song birds, game birds and squirrels. This was verified by the presence of the Gray Squirrel, as well as a Rose-breasted Grosbeak and an Indigo Bunting (see photo), both of which took intermittent breaks to sing, but spent most of their time consuming elm seeds.
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